REVIEW

Br. J. Biomed. Sci., 27 November 2025

Volume 82 - 2025 | https://doi.org/10.3389/bjbs.2025.15375

Mitochondrial DNA Mutations and Epigenetic Regulation in Type 2 Diabetes Mellitus Development

  • 1. School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Selangor Darul Ehsan, Malaysia

  • 2. School of Life Sciences, Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham, United Kingdom

  • 3. Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia

  • 4. Monash University Malaysia Genomics Platform, School of Science, Monash University Malaysia, Bandar Sunway, Selangor Darul Ehsan, Malaysia

  • 5. School of Biosciences, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Selangor Darul Ehsan, Malaysia

Article metrics

316

Views

Abstract

The global prevalence of type 2 diabetes mellitus (T2DM) has increased significantly over the past decade and is projected to rise further. While genetic and lifestyle factors are well-established contributors to T2DM pathogenesis, mitochondria have also gained attention as the key players. Many studies suggested that mitochondrial DNA (mtDNA) mutations and epigenetic modifications were implicated in the development and progression of T2DM. This review aimed to provide a comprehensive analysis of mtDNA mutations and epigenetic modifications associated with T2DM. Based on data from 30 published studies, a total of 117 mtDNA mutations were identified to be associated with T2DM, with D-loop region being the mutation hotspot. However, it was reported that the majority of D-loop mutations were also more frequently observed in healthy populations compared to mutations in other mtDNA regions, suggesting their potential non-pathogenic characteristic. Thus, mtDNA mutations found to be associated with T2DM but with lower occurrence in healthy populations may play a more significant role in influencing T2DM susceptibility. Regarding epigenetic modifications, mtDNA methylation was commonly reported in the D-loop and ND6 regions across seven studies. These findings suggested that these regions may play critical roles in the regulation of mitochondrial gene expression under diabetic conditions. Lastly, this review also discussed the technical challenges and limitations of detecting mtDNA mutations and methylation changes. In addition, relevant ethical considerations surrounding mitochondrial genetic research were also addressed. In conclusion, mtDNA mutations and methylation changes could potentially serve as biomarkers for the development and progression of T2DM. These molecular modifications may offer valuable insights for early diagnosis and preventive strategies. However, further research and validation are essential to establish their clinical significance and diagnostic utility.

Introduction

Diabetes mellitus (DM) is recognised as one of the fastest expanding global health crises. In 2024, approximately 589 million adults aged between 20 and 79 were reported to have DM, which is estimated to increase to 853 million adults by 2050 [1]. Notably, around 90% of diabetes cases globally are attributed to type 2 diabetes mellitus (T2DM) [2, 3]. Adding to this concern, T2DM incidence among individuals aged 15 to 39 rose by 56% between 1990 and 2019, further emphasising the urgent need to address this disease [4].

DM is characterised by increased blood glucose levels, often due to impaired insulin secretion from the pancreas, insulin resistance (IR) in peripheral tissues, or both [2]. Insulin is an important hormone secreted by the pancreatic β-cells, which facilitates glucose uptake from bloodstream into cells for energy production or storage [1]. Additionally, it plays a key role in inhibiting hepatic gluconeogenesis [5]. Therefore, reduced insulin production or sensitivity can lead to increased blood glucose levels.

It has been proposed that both genetic and epigenetic factors may influence the development of T2DM [6]. Although genome-wide association studies have identified several common genetic mutations associated with glycaemic traits (e.g., fasting glucose, fasting insulin, insulin secretion and insulin sensitivity), these account for only about 10%–20% of the variance in these traits [7]. This suggests that factors other than nuclear DNA may also play a significant role in T2DM development. In this context, mitochondrial DNA (mtDNA) is thought to affect T2DM progression, in which mutations or epigenetic modifications in mtDNA may disrupt glucose homeostasis. Although studies have been conducted to determine mtDNA mutations related to T2DM, research on mtDNA epigenetic modifications remains limited and less well-documented.

Thus, this review summarises findings from 1994 to 2024 on the link between mtDNA mutations, epigenetic modifications, and T2DM, with most studies published within the past decade. The challenges and limitations to the profiling of mtDNA mutations and methylation have also been addressed. The discovery of mutations or epigenetic variations associated with T2DM susceptibility may enable earlier diagnosis or prevention. Additionally, mtDNA epigenetic profile may serve as a valuable indicator for assessing treatment efficacy or disease progression, contributing to a significant milestone in clinical advancement.

Mitochondrial DNA Mutations in the Development of T2DM

Mitochondria and Mitochondrial DNA

Mitochondria are frequently referred to as the “powerhouse of the cell” due to their essential role in adenosine triphosphate (ATP) synthesis through oxidative phosphorylation. They also play several crucial metabolic roles, such as intracellular calcium homeostasis, reactive oxygen species (ROS) production, synthesis of haem and iron-sulphur clusters [810]. Furthermore, they play a central role in regulating programmed cell death by responding to the pro- and anti-apoptotic signals to maintain tissue homeostasis [11].

Mitochondria are distinct from other cytoplasmic organelles as they contain their own DNA, which encodes essential RNAs and proteins [12]. Human mtDNA encodes only 37 genes due to the evolutionary loss or transfer of most mitochondrial genes to nuclear DNA [13]. Among these, 22 genes encode for tRNAs, 2 rRNAs (12S and 16S) and 13 are protein-coding genes (Figure 1) [13]. Unlike traditional Mendelian genetics, mtDNA is inherited maternally as a haploid molecule, allowing mutant mtDNA to accumulate and be passed from mother to offspring [15, 16].

FIGURE 1

Diagram of human mitochondrial DNA, showing a circular genome of 16,569 base pairs. It includes regions for rRNA, tRNA, and subunits of complexes I, III, IV, and V. The D-loop, a non-coding region, is indicated. Color coding distinguishes between different gene types, with a legend on the right.

The human mitochondrial DNA. The outer circle indicates the H-strand, while the dotted line indicates the L-strand. Human mitochondrial DNA only encodes for 37 genes, namely 13 OXPHOS protein-coding genes, 22 tRNAs and 2 rRNAs [14]. H-strand: heavy strand; L-strand: light strand; OH: origin of H-strand synthesis; OL: origin of L-strand synthesis; HSP: promoter for transcription of heavy strand; LSP: promoter for transcription of light strand; bp: base pairs; D-loop: displacement loop: rRNA: ribosomal RNA; ND: NADH dehydrogenase; COX: cytochrome c oxidase; ATP: ATP synthase; Cyt b: Cytochrome b; tRNAs for F: Phenylalanine; V: Valine; L: Leucine; I: Isoleucine; Q: Glutamine; M: Methionine; W: Tryptophan; A: Alanine; N: Asparagine; C: Cysteine; Y: Tyrosine; S: Serine; D: Aspartic acid; K: Lysine; G: Glycine; R: Arginine; H: Histidine; E: Glutamic acid; T: Threonine; P: Proline; OXPHOS: oxidative phosphorylation.

Human mtDNA is a circular, polycistronic, double-stranded molecule made up of 16,569 base pairs (bp) and lacks introns (Figure 1) [17]. The nucleotide content of each strand differs, whereby the light strand (L-strand) is rich in cytosine, while the heavy strand (H-strand) is rich in guanine [17]. Next, mtDNA possesses a triple-stranded displacement loop structure known as displacement loop (D-loop), which is a non-coding region that acts as the promoter for both strands [18]. The D-loop regulates mtDNA replication, optimising the mtDNA copy numbers according to the cellular energy demands [19, 20].

Oxidative Stress and Mitochondrial Dysfunction

In mitochondria, ROS (e.g., superoxide radicals, hydrogen peroxide and hydroxyl radicals) are inevitably produced due to the continuous oxidative phosphorylation activity, accounting for approximately 90% of cellular ROS [21, 22]. Under normal circumstances, the cells possess defence mechanisms to counteract ROS generation [23]. For instance, the cells possess antioxidant enzymes that neutralise ROS, including superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, thioredoxin reductase, thioredoxin and peroxiredoxin [23, 24]. In addition to enzymatic antioxidants, mitochondria contain low molecular weight antioxidants (e.g., coenzyme Q) and repair mechanisms that help mitigate oxidative damage [23]. However, excessive ROS production can still be induced by stress factors, leading to excessive electrons being transferred to oxygen in the electron transport chain without ATP production [25].

Excessive ROS production has been implicated in causing oxidative damage to DNA, contributing to the development of various diseases [26]. It has been strongly associated with mitochondrial dysfunction, resulting in increased mutation rates, reduced mitochondrial biogenesis and accelerated aging [25, 27]. The ROS-induced mitochondrial dysfunction further suppresses ATP production while increasing ROS production, creating the ‘vicious cycle’ that ultimately leads to insulin resistance and onset of DM [25]. Additionally, excessive ROS disrupts the phosphorylation of insulin receptor substrate proteins by serine kinases, which is a critical initial step in the insulin signalling pathway [28].

In turn, insulin resistance or DM can further disrupt the mitochondrial metabolism, causing reduced insulin secretion from pancreatic β-cells, enhanced mitochondrial permeability transition, or increased mitochondrial apoptosis [29, 30]. Studies conducted on the relationship between mitochondrial mutations, mitochondrial dysfunctions and T2DM supported the involvement of mitochondria in T2DM development [31].

Mitochondrial DNA Mutations and T2DM

Mutation is a permanent and heritable alteration in DNA that often leads to changes in protein function [32]. It can also affect the structure and function of non-coding RNAs such as tRNA and rRNA [33]. Mutations may happen spontaneously or be induced by ROS. MtDNA is particularly susceptible to mutation due to its haploid nature and the close proximity to ROS production site, as aforementioned [21, 34]. Additionally, mtDNA lacks protective histones, leaving it more exposed to damage induced by ROS or other mutagens [21]. Moreover, unlike nuclear DNA, mtDNA lacks sufficient repair mechanisms to correct mutation and maintain normal mitochondrial function [35]. This susceptibility of mtDNA to mutation has led to the concept of a ‘vicious cycle’, in which initial ROS-induced mitochondrial dysfunction triggers further ROS production, subsequently exacerbating mitochondrial damage and dysfunction [21].

Recent studies have identified mtDNA mutations as potential contributors to the development of DM. Several mtDNA mutations associated with DM in various populations have been reported (Table 1). Beyond identifying mutations detected in diabetic individuals, it is equally important to determine whether these mutations also occur frequently in healthy individuals. Therefore, gnomAD 3.1 and Helix frequencies were included, which acted as the indicators of whether specific mutations are commonly found in healthy individuals, rather than exclusively in diabetic individuals [3739]. In most cases, a mutation that appears at high frequency in healthy populations is likely a non-pathogenic polymorphism or mutation hotspot. Thus, the potentially significant mutations were highlighted in bold in Table 1, as they might be the more reliable indicators for different forms of DM.

TABLE 1

mtDNA region Mutationa No. of haplogroups reported from PhyloTree 17.0 [36] gnomAD 3.1 frequency (%)b [37, 38] Helix Frequency (%)c [37, 39] Patient report from Mitomap [37] Population(s) identified by studies Type(s) of DM/IR identified References
D-loop A16051G 25 2.529 2.580 N/A Bangladeshi T2DM [40]
T16093C 57 5.311 2.590 N/A Uyghur; Chinese; not specified T2DM/MIDD [4144]
T16126C 21 14.321 17.653 N/A Bangladeshi; not specified T2DM [40, 44]
G16129A 93 11.526 7.282 N/A Bangladeshi T2DM [40]
C16186T 3 1.386 NR N/A Arab T2DM [45]
T16189C 117 24.856 NR Reported DM Italian; bangladeshi; caucasian; Chinese; not specified T2DM [40, 41, 4648]
C16223T 33 39.409 18.185 N/A Bangladeshi; not specified T2DM [40, 49]
C16270T 18 8.836 7.629 N/A Moroccan T2DM [50]
G16274A 36 1.381 1.079 N/A Arab T1DM/T2DM [45]
C16292T 24 3.466 2.477 N/A Arab T2DM [45]
C16294T 31 14.190 10.619 N/A Arab T2DM [45]
T16311C 147 21.850 17.076 N/A Bangladeshi T1DM [40]
G16319A 39 6.228 4.645 N/A Bangladeshi T2DM [40]
C16320T 25 4.753 1.710 N/A Moroccan T2DM [50]
T16519C High 65.725 64.287 N/A Italian; not specified T2DM [41, 46]
T58C 1 0.025 0.067 N/A Not specified T2DM [41]
C150T 76 16.628 10.078 N/A Arab T2DM [45]
C151T 42 3.544 1.553 N/A Not specified T2DM [41]
T195C 124 27.606 17.602 N/A Arab T2DM [45]
568 poly C - - - N/A Not specified MIDD [41, 51]
12S RNA T1189C 3 4.005 5.965 N/A Not specified T2DM [49]
C1310T 2 0.034 0.048 N/A Japanese; not specified T2DM [41, 52]
A1382C - 0.066 0.079 Reported T2DM susceptibility Not specified T2DM [41]
T1420C 2 0.353 0.139 N/A Not specified T2DM [49]
A1438G 14 95.610 96.891 N/A Japanese T2DM [52]
16S RNA G1719A 28 4.033 5.127 N/A Arab T2DM [45]
A1811G 7 8.794 12.126 N/A Not specified T2DM [49]
G1888A 14 6.360 9.489 N/A Arab T2DM [45]
T2667C - 0.009 0.009 N/A Not specified T2DM [49]
A2706G 10 73.949 63.340 N/A Uyghur T2DM [43]
T3027C 8 0.236 0.366 N/A Not specified T2DM [49]
A3156G - 0.007 0.007 N/A Not specified T1DM/T2DM [41]
T3200C 2 0.090 0.055 N/A Not specified T2DM [41]
tRNA leu A3243G - 0.000 0.001 Confirmed pathogenic MELAS/MIDD Chinese; Uyghur; Japanese; Indian; not specified T1DM/T2DM/MIDD/GDM [41, 43, 5356]
C3254A 1 0.243 0.041 Reported GDM Singaporean; not specified GDM [41, 57]
C3256T - NR NR Confirmed likely pathogenic MELAS Not specified T2DM/MIDD [41, 44]
T3264C - 0.000 0.001 Reported DM Japanese; not specified MIDD/MDM [41, 58]
T3271C - 0.000 0.000 Confirmed pathogenic MELAS/DM Chinese T2DM/MIDD [56]
T3290C 6 0.145 0.096 N/A Not specified T2DM/MIDD [41, 44]
A3302G - 0.000 0.000 N/A Not specified PCOS-IR [41]
ND1 G3316A 12 0.457 0.495 hg D1, D2, M33, R30 markerd; reported DM Indonesian; Mizo; not specified T2DM [41, 44, 59, 60]
G3357A 2 0.044 0.059 N/A Not specified T1DM/T2DM [41]
C3375A - NR NR N/A Not specified T1DM/T2DM [41]
T3394C 8 0.911 1.085 hg M9 markerd; reported DM Chinese; Indonesian; Mizo; not specified T1DM/T2DM [41, 44, 48, 59, 60]
T3398C 7 0.239 0.270 Reported GDM Singaporean; not specified GDM [41, 57]
A3399T 2 0.005 0.009 Reported GDM Singaporean; not specified GDM [41, 57]
G3483A 6 0.190 0.173 N/A Not specified T2DM [44]
T3548C 4 0.034 0.036 N/A Not specified MIDD [41]
C3970T 2 0.588 0.581 N/A Mizo T2DM [60]
tRNA Ile G4284A - 0.007 0.001 N/A Not specified MIDD [41]
tRNA Met A4435G 2 0.041 0.066 N/A Chinese T2DM [56]
C4467A - NR NR N/A Chinese T2DM [56]
ND2 G4491A 8 0.298 0.384 N/A Not specified T2DM [41]
A4769G 6 98.387 97.684 N/A Arab T2DM [45]
A5178C - NR NR N/A Japanese; not specified T1DM/T2DM [41, 49]
tRNA Trp A5514G 1 0.005 0.015 N/A Chinese T2DM [56, 61]
tRNA Ala T5587C 1 0.012 0.015 Reported MIDD Chinese T2DM [56]
T5628C 1 0.096 0.086 N/A Chinese MDM [62]
A5655G 2 NR NR N/A Chinese T2DM [56]
tRNA Cys/tRNA Tyr A5826G 1 NR NR N/A Chinese T2DM [63]
COXI G5913A 2 0.530 0.633 N/A Not specified MIDD [41]
C7028T 2 74.940 63.008 N/A Uyghur T2DM [43]
tRNA Ser C7502T - 0.009 0.003 N/A Chinese T2DM [56]
T7505C - NR 0.001 N/A Chinese T2DM [56]
tRNA Lys 8,281 9bp 19 NR NR N/A Not specified MIDD [41, 51]
A8296G 3 0.044 0.048 N/A Chinese MIDD [56]
G8313A - 0.000 NR N/A Indian; not specified T2DM [41, 53]
A8344G - 0.000 0.000 N/A Not specified T2DM/GDM [41]
A8348G 2 0.094 0.151 N/A Not specified MIDD [41]
T8356C - 0.000 0.000 N/A Not specified T2DM [41]
ATP8 C8478T 2 0.486 0.704 N/A Not specified MIDD [41]
T8414G 1 NR NR N/A Uyghur; not specified T2DM [41, 43]
C8393T 2 0.028 0.040 N/A Not specified MIDD [41]
Region between ATP8 and ATP6 T8551C - 0.018 0.020 N/A Not specified MIDD [41]
C8561G - NR NR Reported DM Not specified T2DM [41]
ATP6 A8701G 10 30.319 8.753 N/A Mizo T2DM [60]
A8860G 4 99.381 98.774 N/A Not specified MIDD [41]
COXIII G9267C - NR NR Reported MIDD Not specified MIDD [41]
T9540C 1 30.433 8.791 N/A Mizo T1DM [64]
A9827G - NR NR N/A Not specified T1DM [41]
tRNA Gly T10003C 1 0.025 0.068 Reported MIDD Chinese; not specified T2DM/MIDD [41, 56]
A10055G - 0.004 0.004 N/A Chinese T2DM [56]
ND3 A10398G 24 41.848 25.166 hg L, M markerd Mizo; not specified T2DM [44, 64]
C10400T 1 5.275 4.611 N/A Mizo T2DM [64]
tRNA Arg T10463C 5 5.802 8.966 N/A Arab T2DM [45]
ND4L T10873C 1 30.495 8.833 N/A Mizo T2DM [64]
G11696A 6 0.099 0.135 N/A Chinese T2DM [65]
G11914A 48 10.858 5.329 N/A Arab T2DM [45]
A12026G 4 0.108 0.096 Reported DM Japanese; not specified T2DM [41, 52]
tRNA Ser C12237T 2 0.021 0.022 N/A Chinese T2DM [61]
C12258A - NR NR Confirmed likely pathogenic MIDD Not specified MIDD [41, 66]
tRNA Leu A12230G - 0.000 0.000 N/A Chinese T2DM [56]
A12308G 3 15.539 19.993 Reported not pathogenic in hg K and Ud Chinese T2DM [56]
ND5 C12633A 4 1.271 1.893 N/A Arab T2DM [45]
C12705T 2 48.879 18.024 N/A Mizo T2DM [64]
G13368A 12 5.779 8.901 N/A Arab T2DM [45]
G13590A 11 10.851 3.257 N/A Arab T2DM [45]
ND6 G14364A 12 0.489 0.614 N/A Arab T2DM [45]
T14502C 7 0.156 0.195 N/A Chinese T2DM [54]
T14577C 4 0.089 0.179 Reported MIDD Not specified T2DM [41, 49]
tRNA Glu A14692G 1 0.002 0.009 Reported MIDD Chinese MIDD [67]
A14693G 7 0.193 0.187 Reported MELAS Chinese; not specified T2DM/MIDD [41, 48]
T14709C - 0.000 NR Confirmed likely pathogenic MIDD Not specified T2DM [41, 44]
Cytb C14766T 4 70.679 58.525 N/A Not specified T1DM/T2DM [49]
T14783C 2 5.535 4.885 N/A Mizo T2DM [64]
G15043A 7 7.876 7.868 N/A Mizo T2DM [64]
G15148A 10 0.333 0.429 N/A Arab T2DM [45]
G15301A 7 24.462 8.104 N/A Mizo; Arab T2DM [45, 64]
A15326G 9 99.342 98.973 N/A Not specified MIDD [41]
A15607G 4 5.558 8.735 N/A Arab T2DM [45]
A15746G 2 0.236 0.246 N/A Not specified T2DM [41]
tRNA Thr G15897A - 0.000 NR Reported MID Chinese T2DM/MIDD [56, 68]
A15901G 1 0.005 0.002 N/A Japanese T2DM [69]
A15924G 31 4.115 5.064 N/A Chinese; not specified T2DM [44, 56]
C15926T - 0.012 0.028 N/A Japanese T2DM [69]
G15927A 7 0.709 0.920 N/A Chinese; not specified T2DM [44, 56]
G15928A 6 5.609 8.707 N/A Arab; not specified T2DM [44, 45]

Summary of mitochondrial DNA mutations associated with diabetes or insulin resistance.

a

“TxxxxC” represents mitochondrial DNA, point mutation which occurs at position xxxx, where “T” is being replaced by “C”. “xxxx poly C″ represents that the polycytidine tract is variable in length at position xxxx. “xxxx xbp” represents mitochondrial DNA, insertion mutation which occurs at position xxxx, where a repeated sequence of x base pairs is inserted. All mutations positions are reported according to the revised Cambridge Reference Sequence (rCRS, NC_012920.1). Haplogroup associations and presence in healthy individuals were determined using PhyloTree 17.0 and Mitomap. Mutations potentially significant in diabetes are highlighted in bold.

b

The gnomAD, 3.1 frequency refers to the variant frequency in healthy population based on the mitochondrial dataset from the Genome Aggregation Database (gnomAD v3.1). The frequency is derived from 70% Eurasian lineage (N), 25% African lineage (L) and 5% Asian lineage (M).

c

The Helix frequency refers to the variant frequency in healthy population based on the Helix population database. This frequency is derived from 91.2% Eurasian lineage (N), 4.2% African lineage (L) and 4.6% Asian lineage (M).

d

Mitochondrial haplogroup (hg) denotes specific maternal mtDNA, lineages. These markers indicate mtDNA, variants commonly found in specific maternal lineages and may represent population-specific polymorphisms rather than pathogenic mutations.

Haplogroup distribution, variant frequencies in healthy populations (as reported in public databases), clinical reports and examples of studies that observed these mutations in different populations were listed. T1DM: Type 1 diabetes mellitus; T2DM: Type 2 diabetes mellitus; MIDD: maternally inherited diabetes & deafness/mitochondrial diabetes; MID: mitochondrial inherited diabetes; MELAS: mitochondrial encephalopathy, lactic acidosis and stroke-like episodes; GDM: gestational diabetes mellitus; PCOS-IR: insulin resistance in polycystic ovary syndrome; NR: not reported; hg: mitochondrial haplogroup (e.g., D1, D2, M33, R30, M9, L, M, K, U).

It was observed that while a majority of the mutations listed were located in the D-loop region, their frequencies in healthy populations based on both databases, were relatively higher compared to mutations in other regions of the mitochondrial genome. This suggests that many of the D-loop mutations linked to T2DM may represent random, non-pathogenic variants, rather than disease-causing mutations. This interpretation is supported by the fact that D-loop, which plays a key role in regulating mtDNA replication and transcription, is the most variable region of the mitochondrial genome in both healthy and diseased individuals [41]. Nevertheless, it is possible that D-loop mutations may still disrupt mtDNA replication, leading to mtDNA depletion and subsequent mitochondrial dysfunction, contributing indirectly to disease pathology [70].

While D-loop mutations are frequently observed in healthy individuals and likely non-pathogenic, certain other mutations may demonstrate a stronger disease association. For instance, one commonly affected site that is rarely found in healthy population is the tRNALeu gene, where adenine is substituted with guanine at nucleotide position 3243 (m.A3243G) [71, 72]. This mutation is also referred to as the mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) mutation, as it was initially identified in individuals with these clinical manifestations in 1990 [73]. This mutation disrupts the proper folding of tRNA molecule by interfering with key hydrogen bonds between A14 and U8, resulting in increased structural openness, reduced stability and reduced aminoacylation [74, 75]. To compensate, the mutant tRNA may abnormally form dimers with other mutant tRNA molecules, which further reduces the aminoacylation rate [74]. As a result, amino acids may be incorrectly incorporated or entirely omitted during mitochondrial translation, producing defective mitochondrial proteins and ultimately impairing mitochondrial function.

In summary, beyond identifying mutations present in diabetic individuals, it is equally important to assess whether these mutations also occur frequently in healthy populations. This distinction may further refine the understanding of specific genetic factors underlying mitochondrial dysfunction in diabetes, thereby contributing to more efficient risk detection. In this context, oxidative stress represents one of the key factors driving mtDNA mutations due to elevated levels of ROS in mitochondria. Thus, addressing oxidative stress and its effect on mtDNA mutations may offer promising strategies for the prevention or management of mitochondrial dysfunction in T2DM.

Mitoepigenetics in the Development of T2DM

Epigenetics is the study of variations in gene expression that occur without DNA sequence alterations [76]. Key epigenetic mechanisms include DNA methylation, histone modifications and regulation of gene expression by non-coding RNAs (Figure 2) [79]. These mechanisms play important roles in regulating gene expression at the transcriptional, post-transcriptional and translational levels [80]. It is proposed that epigenetics not only occurs in nuclear DNA, but it also affects mtDNA, in which the phenomenon is known as “mitoepigenetics” [81]. The processes underlying mitoepigenetics have not been as thoroughly explored as those governing nuclear DNA, mainly due to the absence of histones in mitochondria [81, 82].

FIGURE 2

Illustration showing epigenetic mechanisms. (A) DNA methylation involves DNMT converting SAM to SAH, adding methyl groups to DNA, and silencing target genes. (B) Histone modification involves acetylation, methylation, phosphorylation, and ubiquitination altering chromatin structure. (C) Non-coding RNA, including miRNA, regulates mRNA by inhibiting translation. The diagram includes labeled nucleosome, DNA, chromatin, and chromosome structures. A key indicates symbols for acetyl, methyl, phosphate groups, and ubiquitin monomer.

The primary mechanisms of epigenetics involve DNA methylation, histone modifications and regulation by non-coding RNAs. (A) DNA methylation involves the addition of a methyl group to the fifth carbon of a cytosine residue. When methylation takes place at gene promoter regions, it usually leads to downregulation of gene expression. (B) Histone modification refers to post-translational modification of histone proteins, such as covalent addition of acetyl, methyl, phosphate groups or ubiquitin monomers. These modifications alter the chromatin structure and affect transcriptional activity. Histone acetylation and phosphorylation typically promote transcription, while methylation is often linked to transcriptional repression. Ubiquitination can either activate or suppress transcription, depending on the context. (C) Non-coding RNAs, such as miRNAs, regulate gene expression post-transcriptionally. When binding to target mRNAs, miRNAs either inhibit translation or promote mRNA degradation, thus silencing gene expression. DNMTs: DNA methyltransferases; SAM: S-adenosylmethionine; SAH: S-adenosylhomocysteine. Adapted and modified with permission from Low et al. [77]. Additional details from Liu et al. [78].

While some studies suggest that methylation is a distinct feature of nDNA and absent in mtDNA, others provide evidence supporting its presence in mtDNA [8386]. Emerging studies have identified N6-methyldeoxyadenosine (6mA) as an alternative form of mtDNA methylation, mediated by methyltransferase 4 MTA70 (METTL4), alongside the more commonly studied 5-methylcytosine (5-mC) (Figure 3). Notably, the deletion of METTL4 has been shown to reduce 6mA levels in mtDNA [87]. However, studies have reported conflicting findings regarding the primary methylation sites in mtDNA, with evidence suggesting involvement of both CpG and non-CpG sites [9295]. While the majority of studies suggest that methylation primarily occurs at CpG sites, Patil et.al. [93] reported that non-CpG sites are the main targets of methylation in mtDNA. Despite these conflicting findings, one consistent observation is that methylation occurs more frequently on the L-strand compared to the H-strand [9396].

FIGURE 3

Diagram illustrating the proposed mechanism of mitochondrial DNA (mtDNA) methylation and demethylation processes involving adenine(A), N6-methyladenine(6mA), and N6-hydroxymethyladenine (6hmA). Adenine is converted to 6mA through the action of METTL4, while ALKBH1/ALKBH4 reverse this process. ALKBH1 also converts 6mA to 6hmA, which degrades to formaldehyde. In addition, the diagram shows that 6mA can inhibit POLRMT and TFAM, affecting mtDNA transcription.

Proposed mechanisms of mtDNA methylation. Methyltransferase METTL4 catalyses the formation of 6mA on mtDNA, which interferes with the binding of TFAM and POLRMT with mtDNA, thus preventing the assembly of transcription initiation complex. This inhibition reduces mtDNA transcription and impairs mitochondrial function. The 6mA can be removed through oxidative demethylation mediated by ALKBH1 or AKLBH4, which restores adenine to its unmethylated form. Alternatively, ALKBH1 can oxidise 6mA to an unstable intermediate 6hmA, which rapidly degrades into formaldehyde and adenine [8791]. METTL4: methyltransferase 4 MTA70; A: adenine; 6mA: N6-methyladenine; TFAM: transcription factor A; POLRMT: mitochondrial RNA polymerase; ALKBH: alpha-ketoglutarate-dependent dioxygenase homolog; 6hmA: 6-hydroxymethyladenine.

Several studies have suggested that mtDNA methylation serves as a protective mechanism against oxidative damage, which could potentially be induced by high blood glucose concentrations in patients with T2DM [97, 98]. The frequency and sites where mtDNA methylation have been detected in the progression of T2DM and related disorders are summarised in Table 2. An in vitro study showed that diabetic condition increased mtDNA methylation by 1.5- to 3-fold at various regions, including the D-loop, Cytb, ND6 and COXII [99]. Similar findings have also been reported by several in vivo studies. For instance, Kowluru (2020) found higher levels of D-loop methylation in the retinal microvasculature of T2DM rats [100]. Meanwhile, another study reported significant methylation at the ND1, ND2, ND6, CYTB and COX1 regions in diabetic mice [95]. The latter study also found significant higher methylation of ND6 in T2DM human subjects compared to healthy controls [95]. Notably, IR subjects displayed significant 4.6-fold increase in DNA methylation compared to insulin-sensitive subjects [103].

TABLE 2

Experimental model mtDNA Region(s) investigated Key Observation(s) References
Cell culture
High glucose (20 mM) treated in vitro cultured bovine retinal endothelial cells and human retinal microvasculature D-loop, Cytb, ND6 and COXII Increased methylation, decreased mtDNA transcription and increased DNMT1 binding were observed at D-loop. Methylation levels were significantly higher at D-loop compared to Cytb and COXII regions (p < 0.05). This resulted in significant inhibition of the mitochondrial gene expression critical for electron transport chain activity (p < 0.05) [99]
Animal model
Hepatic mtDNA from db/db mice 13 mtDNA-encoded genes Significant methylation was observed at ND2, ND5, ND6, COX1 and ATP8 regions, with ND6 region showing the highest methylation level under diabetic conditions due to enhanced mitochondrial translocation of DNMT1 (p < 0.05) [95]
Retinal microvasculature from T2DM, T1DM diabetes rat models, and high-fat diet rat models D-loop D-loop methylation level was higher in the T2DM group compared to the T1DM or high-fat diet group [100]
Clinical studies
Peripheral leukocytes from 39 obese and 39 non-obese human subjects ND6 Significant increased ND6 methylation was observed in T2DM subjects compared to healthy controls. ND6 methylation level was inversely correlated with ND6 expression and positively correlated with metabolic parameters including body mass index, fasting glucose, fasting insulin and insulin resistance index (p < 0.05) [95]
Buccal swabs from 69 young caucasian individuals D-loop D-loop methylation was significantly higher in overweight females than lean females. Increased methylation was associated with reduced mtDNA copy number, and mtDNA copy number showed a negative correlation with BMI in females (p < 0.05) [101]
Leukocytes from fasting blood samples of 8 lean and 32 obese/overweight participants D-loop and ND6 D-loop and ND6 methylation levels were significantly correlated with insulin resistance indices (p < 0.05) [102]
Leukocytes from fasting blood samples of 40 participants without diabetes or cardiovascular disease D-loop A 5.2-fold increase of D-loop methylation was observed in obese than in lean subjects; A 4.6-fold increase of D-loop methylation was observed in insulin-resistant than in insulin-sensitive subjects
Liver biopsies from 45 NAFLD patients and 18 with near-normal histology D-loop, ND6 and COX1 Methylated/unmethylated ND6 ratio was significantly correlated with NAFLD activity score, whereas D-loop and COX1 methylation were not correlated with disease severity

mtDNA methylation studies in T2DM or related disorders.

Limited clinical research has been conducted to characterise the mtDNA methylation profile in T2DM subjects. However, since T2DM is often associated with obesity or being overweight, studying the methylation profile in such individuals may provide valuable insights. For example, a clinical study reported that increased methylation at specific CpG sites in the D-loop was significantly (p = 0.003) associated with body mass index (BMI) percentiles >85th in female subjects [101]. Similar observations were made in an earlier mixed-gender study, in which a 5.2-fold increase in D-loop methylation was observed in obese subjects compared to lean subjects [103]. This was further supported by a subsequent study that revealed a drastic elevation of methylation levels at ND6 and D-loop regions as BMI increased [102].

Research has also demonstrated the common coexistence of non-alcoholic fatty liver disease (NAFLD) and T2DM. Specifically, NAFLD increases the risk of T2DM by 2- to 5-fold, with about 59.67% of T2DM patients also having NAFLD [104, 105]. This connection suggests that the methylation profile in individuals with NAFLD may be linked to T2DM. For instance, one study reported a significant positive association (p < 0.04) between the methylated-to-unmethylated ratio of mt-ND6 and the severity of NAFL, with methylation levels increasing from 20.6% in simple steatosis to 28.4% in non-alcoholic steatohepatitis [106].

In summary, increased mtDNA methylation is a response to various stress factors in disease states to protect mtDNA from damage and potential mutations. Several findings have indicated that mtDNA methylation profile contains relevant information about body composition and the associated risk of developing diseases such as T2DM. Given its roles in gene expression regulation, the potential of epigenetics in disease development or prevention warrants further research. Consequently, these epigenetic profiles might be a useful indicator for early molecular detection or prevention, as they are often detectable in the early stages of disease progression [107].

Limitations and Challenges in Sequencing Mitochondrial DNA Mutations and Mitochondrial Epigenetic Modifications

While research on mtDNA mutations and epigenetic modifications has advanced the understanding of mitochondrial regulation in T2DM, the accurate detection of these changes remains technically challenging. To date, hundreds of thousands of human mitogenomes have been sequenced using traditional Sanger methods, as well as a range of modern high-throughput sequencing platforms. Meanwhile, studies on the mitoepigenome remain limited but are getting increasing attentions with advancements in sequencing technologies. These sequencing technologies typically involve several steps including DNA isolation, library preparation and sequencing that uses various chemistries, flow-cells and detection systems utilizing base-specific color-coded fluorescence, light emissions, current, or ions changes. This is followed by bioinformatics analysis and each stage of the process presents unique challenges, making mtDNA sequencing particularly challenging.

Mitochondrial DNA Isolation and Purification

The initial step of isolating and enriching pure mtDNA relative to nuclear DNA remains challenging. Contamination with nuclear DNA, including mitochondrial pseudogenes in the lysate, can introduce artifacts during mtDNA analysis, particularly with short-read lengths [108]. Various conventional isolation techniques have been used, such as differential centrifugation, density gradient centrifugation, magnetic bead-based and mitochondrial isolation followed by DNA extraction [109111]. Several commercial kits for direct mtDNA extraction are widely available. One study has also demonstrated a novel approach for mtDNA isolation and enrichment using a plasmid isolation kit, followed by additional purification with solid-phase reversible immobilisation on paramagnetic beads and limited polymerase chain reaction (PCR) amplification [112]. However, a very high cell number, typically ranging from 5 to 17 million cells is required from cell culture and patient samples to obtain sufficient mtDNA yield for sequencing, regardless of the method used [110, 112]. This requirement may be impractical for certain studies, particularly those involving clinical samples, which are often scarce.

Other options include DNA extraction followed by target enrichment of mtDNA by either long-range PCR amplification or complementary oligonucleotide probe hybridization. Targeted amplification may be suitable for direct sequencing but sequencing artefacts may be introduced during the DNA amplification, which may lead to false positive or negative results [113]. Moreover, mtDNA enrichment via PCR amplification is unsuitable for methylation sequencing, as PCR does not preserve methylation marks (such as 5-mC), compromising accurate quantification of mtDNA methylation [112, 114]. A mtDNA isolation method capable of providing high yield and enrichment with minimal or no amplification is ideal for downstream methylation sequencing and improvements are still needed in DNA extraction methods and protocols for investigation of epigenetic markers in an unbiased manner.

Sequencing Methods

Sequencing technologies are categorised into first-, second- and third-generation methods, with the latter two often referred as next-generation sequencing (NGS) [115]. The selection of an appropriate sequencing technology depends on the specific research question being asked. Different sequencing methods and platforms exhibit varying degrees of error rates, ranging from 0.1% to 5% as compared to the lower error rate of Sanger sequencing (0.001%) [113, 116122]. Although these error rates might seem to be negligible, their cumulative effect can become significant given the vast size of the human nuclear genome [113].

Sanger sequencing (first-generation) is considered the gold standard due to its high accuracy despite its short-read limitations, but it is expensive compared to the newer technologies that have gained popularity, particularly for human whole genome sequencing [113]. These technologies have been increasingly integrated into clinical diagnostic practices, enabling a holistic analysis of genetic variants in targeted or complete genomes [123].

Besides characterizing genetic variants, it is worthwhile to study epigenetic changes, as epigenetic modifications can be influenced by external factors (e.g., lifestyle factors or intervention). If an individual is diagnosed with a particular genetic variant associated with a specific disease, epigenetic changes may be useful to control or switch off the expression of the specific gene through DNA methylation. By understanding both genetic variants and epigenetic changes in an individual or population, it is possible to offer a more targeted treatment which may potentially reduce the disease occurrence.

Bisulfite conversion with or without PCR amplification is generally used for methylation and mutation sequencing. In methylation sequencing, incomplete conversion of unmethylated cytosine to uracil followed by PCR amplification can lead to overestimation of methylation levels [124]. For mutation sequencing or other applications, biases may arise when short sequences or those with extreme GC content are preferentially or non-preferentially amplified [125]. Although reducing PCR cycles has been proposed as a strategy to minimise bias, research has shown limited improvement with an even lower correlation [125].

While methods such as bisulfite sequencing and methylated DNA immunoprecipitation (MeDIP) are commonly used to study epigenetic modifications, recent advances have enabled PCR-free sequencing approaches that bypass the need for bisulfite conversion. Platforms such as Illumina and Oxford Nanopore have been used for mtDNA sequencing, each offering distinct advantages and limitations (Table 3). Although PacBio technology has the potential to sequence full-length DNA without involving PCR amplification and bisulfite treatment, its application in detecting mtDNA methylation remains limited and underexplored in the current literature.

TABLE 3

Sequencing methods Epigenetic mark detected PCR/Bisulfite conversion Advantages Limitations References
Illumina 5-mC Yes - Used mtDNA-specific primer sets to exclude nuclear mtDNA segments - Required fragmented DNA.
- Introduced bias due to bisulfite conversion and PCR amplification
[126]
5-mC Yes [127]
5-mC Yes [128]
Nanopore sequencing 5-mC No - Enabled direct sequencing of linearised long read mtDNA or gDNA.
- Excluded possible nuclear mtDNA segments from analysis
- Overcame bias introduced by bisulfite conversion and PCR amplification
- Detected both 5-mC and 6mA methylation marks
- Required high read depth to accurately detect methylation, increasing the cost [96]
5-mC Both PCR-amplified and native mtDNA were used [129]
5-mC (applicable for 6mA) Long-range PCR was used [130]
5-mC No [131]
Pyrosequencing 5-mC Yes - Offered lower cost, suitable for validation studies
- Provided precise quantification (%) of methylation at specific CpG sites
- Introduced bias due to bisulfite conversion and PCR amplification
- Limited to short, targeted reads
[127]
5-mC Yes [132]
5-mC Yes [133]
5-mC Yes [134]
PacBio single molecule real-time sequencing 6mA PCR was used - Enabled direct sequencing of mtDNA or gDNA.
- Overcame bias introduced by bisulfite conversion
- Detected both 5-mC and 6mA methylation marks
- Potentially misidentified 5-mC as 6mA
- Introduced bias due to PCR amplification
[135]

Sequencing methods used for the detection of epigenetic modifications in mtDNA.

Data Analysis and Validation

After a successful sequencing run, the large volume of sequencing data requires extensive bioinformatics expertise for analysis to identify significant mutations or epigenetic changes. The computational analysis typically involves three essential steps: (1) Data processing and quality control to ensure accuracy, (2) Data visualisation and statistical analysis to identify patterns and trends, and (3) Validation and interpretation to confirm findings and assess their significance [136]. While minimising error rates remains a key objective for reliable results, ongoing optimisation is still required for different sequencing methods. Despite the availability of various analytical tools, a clear guideline for analysis settings and thresholds has yet to be established [136]. Different studies have adopted different approaches, often employing multiple software tools at different stages [137]. This lack of standardisation poses significant challenges in sequencing analysis. Additionally, comparing results across studies using different analysis methods can further complicate data interpretation.

Ethical Issues

Gene sequencing can reveal extensive genetic information, including adverse functional alleles of protein-coding genes and private individual variations that can be used to identify patients or their close relatives [138]. This raises ethical dilemmas regarding the disclosure of results to the individual or their relatives [139]. While increased awareness of potential hereditary conditions may promote healthier lifestyles, it can also lead to excessive anxiety or detrimental effect on individuals’ perspectives on their health and psychological wellbeing [140, 141].

In cases of maternally inherited mitochondrial diseases, caused by mtDNA mutations, several alternative strategies have been suggested to reduce or prevent the transmission of mtDNA from mother to child. These strategies include egg donation, prenatal testing, preimplantation genetic diagnosis and mitochondrial donation, all raising ethical concerns. Egg donation results in the child being genetically related to only one biological parent without the mitochondrial disease. Prenatal testing and preimplantation genetic diagnosis may risk the pregnancy and bring additional emotional burden on parents in deciding on whether to continue or prematurely terminate the pregnancy, if mitochondrial disease is detected [142]. Mitochondrial donation may be a more permissible approach as only the child’s mtDNA is replaced with mtDNA from a healthy donor while the nuclear DNA remain from both the biological parents [142]. However, concerns remain regarding the technical practicalities of complete faulty mtDNA replacement, as well as potential mismatches between the mtDNA haplotypes of the biological and donor mothers [142].

Conclusions

The increasing prevalence of T2DM in recent decades, along with its future projections and prevalence have raised global concerns. In response, numerous initiatives have been introduced worldwide to promote healthier lifestyles and lower the risk of T2DM. However, while lifestyle factors can have a significant impact on T2DM development, it is also essential to acknowledge the significant influence of inherited genetic factors. Although these genetic predispositions are difficult to alter, epigenetic mechanisms may offer a potential means to regulate harmful gene expression patterns that may contribute to the increased risk of developing T2DM.

This review highlights the emerging roles of mtDNA mutations and epigenetics in the pathogenesis of T2DM. Evidence suggests that alterations in mitochondrial gene expression and function may significantly impair metabolism, leading to T2DM. Given the interplay between inherited genetic predisposition and epigenetic regulation, future research should prioritise large-scale clinical trials to investigate these relationships and susceptibility to T2DM in diverse populations. By integrating genetic background and epigenetic modifications, a more advanced personalised treatment for T2DM could be developed to prevent the development and progression of T2DM.

Statements

Author contributions

The manuscript was written by MK. All authors contributed to the article and approved the submitted version.

Funding

The authors declare that financial support was received for the research and/or publication of this article. This work was funded by the Ministry of Higher Education Malaysia for the grant FRGS/1/2023/SKK10/UNIM/02/1 awarded to Y-FP. Sincere gratitude is also extended to the University of Nottingham Malaysia for providing full tuition fee waiver to MK.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The authors declare that Generative AI was used in the creation of this manuscript. During the preparation of this work, MK used ChatGPT (OpenAI, GPT-4, https://chat.openai.com) to check for grammar and sentence clarity. The final content is reviewed and edited by the authors.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

References

  • 1.

    International Diabetes Federation. IDF Diabetes Atlas. 11th ed. (2025). Available online at: https://idf.org/about-diabetes/diabetes-facts-figures/(Accessed June 5, 2025).

  • 2.

    Goyal R Singhal M Jialal I . Type 2 Diabetes. Statpearls. Treasure Island (FL): StatPearls Publishing (2023).

  • 3.

    Roden M Shulman GI . The Integrative Biology of Type 2 Diabetes. Nature (2019) 576:5160. 10.1038/s41586-019-1797-8

  • 4.

    Xie J Wang M Long Z Ning H Li J Cao Y et al Global Burden of Type 2 Diabetes in Adolescents and Young Adults, 1990-2019: Systematic Analysis of the Global Burden of Disease Study (2019). BMJ (2022) 379:e072385. 10.1136/bmj-2022-072385

  • 5.

    Saltiel AR Kahn CR . Insulin Signalling and the Regulation of Glucose and Lipid Metabolism. Nature (2001) 414:799806. 10.1038/414799a

  • 6.

    Galicia-Garcia U Benito-Vicente A Jebari S Larrea-Sebal A Siddiqi H Uribe KB et al Pathophysiology of Type 2 Diabetes Mellitus. Int J Mol Sci (2020) 21:6275. 10.3390/ijms21176275

  • 7.

    Grarup N Sandholt CH Hansen T Pedersen O . Genetic Susceptibility to Type 2 Diabetes and Obesity: From Genome-Wide Association Studies to Rare Variants and Beyond. Diabetologia (2014) 57:152841. 10.1007/s00125-014-3270-4

  • 8.

    Panda S Behera S Alam MF Syed GH . Endoplasmic Reticulum and Mitochondrial Calcium Homeostasis: The Interplay With Viruses. Mitochondrion (2021) 58:22742. 10.1016/j.mito.2021.03.008

  • 9.

    Picard M Trumpff C Burelle Y . Mitochondrial Psychobiology: Foundations and Applications. Curr Opin Behav Sci (2019) 28:14251. 10.1016/j.cobeha.2019.04.015

  • 10.

    Yien YY Perfetto M . Regulation of Heme Synthesis by Mitochondrial Homeostasis Proteins. Front Cell Dev Biol (2022) 10:895521. 10.3389/fcell.2022.895521

  • 11.

    Vringer E Tait SWG . Mitochondria and Cell Death-Associated Inflammation. Cell Death Differ (2023) 30:30412. 10.1038/s41418-022-01094-w

  • 12.

    Cooper GM . The Cell: A Molecular Approach. 2nd ed. Sunderland (MA): Sinauer Associates (2000).

  • 13.

    Gustafsson CM Falkenberg M Larsson N-G . Maintenance and Expression of Mammalian Mitochondrial DNA. Annu Rev Biochem (2016) 85:13360. 10.1146/annurev-biochem-060815-014402

  • 14.

    Yusoff AAM . Role of Mitochondrial DNA Mutations in Brain Tumors: A Mini-Review. J Cancer Res Ther (2015) 11:53544. 10.4103/0973-1482.161925

  • 15.

    Protasoni M Zeviani M . Mitochondrial Structure and Bioenergetics in Normal and Disease Conditions. Int J Mol Sci (2021) 22:586. 10.3390/ijms22020586

  • 16.

    Giles RE Blanc H Cann HM Wallace DC . Maternal Inheritance of Human Mitochondrial DNA. Proc Natl Acad Sci USA (1980) 77:67159. 10.1073/pnas.77.11.6715

  • 17.

    Chinnery PF Hudson G . Mitochondrial Genetics. Br Med Bull (2013) 106:13559. 10.1093/bmb/ldt017

  • 18.

    Sharma H Singh A Sharma C Jain S Singh N . Mutations in the Mitochondrial DNA D-loop Region Are Frequent in Cervical Cancer. Cancer Cell Int (2005) 5:34. 10.1186/1475-2867-5-34

  • 19.

    Pereira F Soares P Carneiro J Pereira L Richards MB Samuels DC et al Evidence for Variable Selective Pressures at a Large Secondary Structure of the Human Mitochondrial DNA Control Region. Mol Biol Evol (2008) 25:275970. 10.1093/molbev/msn225

  • 20.

    Brown GG Gadaleta G Pepe G Saccone C Sbisà E . Structural Conservation and Variation in the D-loop-containing Region of Vertebrate Mitochondrial DNA. J Mol Biol (1986) 192:50311. 10.1016/0022-2836(86)90272-X

  • 21.

    Balaban RS Nemoto S Finkel T . Mitochondria, Oxidants, and Aging. Cell (2005) 120:48395. 10.1016/j.cell.2005.02.001

  • 22.

    McCord JM . The Evolution of Free Radicals and Oxidative Stress. Am J Med (2000) 108:6529. 10.1016/S0002-9343(00)00412-5

  • 23.

    Napolitano G Fasciolo G Venditti P . Mitochondrial Management of Reactive Oxygen Species. Antioxidants (2021) 10:1824. 10.3390/antiox10111824

  • 24.

    Bhatti JS Bhatti GK Reddy PH . Mitochondrial Dysfunction and Oxidative Stress in Metabolic Disorders — A Step Towards Mitochondria Based Therapeutic Strategies. Biochim Biophys Acta Mol Basis Dis (2017) 1863:106677. 10.1016/j.bbadis.2016.11.010

  • 25.

    Kim J Wei Y Sowers JR . Role of Mitochondrial Dysfunction in Insulin Resistance. Circ Res (2008) 102:40114. 10.1161/CIRCRESAHA.107.165472

  • 26.

    Liu Z Ren Z Zhang J Chuang C-C Kandaswamy E Zhou T et al Role of ROS and Nutritional Antioxidants in Human Diseases. Front Physiol (2018) 9:477. 10.3389/fphys.2018.00477

  • 27.

    Rovira-Llopis S Apostolova N Bañuls C Muntané J Rocha M Victor VM . Mitochondria, the NLRP3 Inflammasome, and Sirtuins in Type 2 Diabetes: New Therapeutic Targets. Antioxid Redox Signal (2018) 29:74991. 10.1089/ars.2017.7313

  • 28.

    Besse-Patin A Estall JL . An Intimate Relationship Between ROS and Insulin Signalling: Implications for Antioxidant Treatment of Fatty Liver Disease. Int J Cell Biol (2014) 2014:519153. 10.1155/2014/519153

  • 29.

    Sivitz WI Yorek MA . Mitochondrial Dysfunction in Diabetes: From Molecular Mechanisms to Functional Significance and Therapeutic Opportunities. Antioxid Redox Signal (2010) 12:53777. 10.1089/ars.2009.2531

  • 30.

    Haythorne E Rohm M van de Bunt M Brereton MF Tarasov AI Blacker TS et al Diabetes Causes Marked Inhibition of Mitochondrial Metabolism in Pancreatic β-Cells. Nat Commun (2019) 10:2474. 10.1038/s41467-019-10189-x

  • 31.

    Rocha M Apostolova N Diaz-Rua R Muntane J Victor VM . Mitochondria and T2D: Role of Autophagy, ER Stress, and Inflammasome. Trends Endocrinol Metab (2020) 31:72541. 10.1016/j.tem.2020.03.004

  • 32.

    Durland J Ahmadian-Moghadam H . Genetics, Mutagenesis. Statpearls. Treasure Island (FL): StatPearls Publishing (2022).

  • 33.

    Xing G Chen Z Cao X . Mitochondrial Rrna and Trna and Hearing Function. Cell Res (2007) 17:22739. 10.1038/sj.cr.7310124

  • 34.

    Neiman M Taylor DR . The Causes of Mutation Accumulation in Mitochondrial Genomes. Proc R Soc B (2009) 276:12019. 10.1098/rspb.2008.1758

  • 35.

    Liao S Chen L Song Z He H . The Fate of Damaged Mitochondrial DNA in the Cell. Biochim Biophys Acta Mol Cell Res (2022) 1869:119233. 10.1016/j.bbamcr.2022.119233

  • 36.

    van Oven M Kayser M . Updated Comprehensive Phylogenetic Tree of Global Human Mitochondrial DNA Variation. Hum Mutat (2009) 30:E38694. 10.1002/humu.20921

  • 37.

    Lott MT Leipzig JN Derbeneva O Xie HM Chalkia D Sarmady M et al Mtdna Variation and Analysis Using Mitomap and Mitomaster. Curr Protoc Bioinformatics (2013) 44:1.23.123.26. 10.1002/0471250953.bi0123s44

  • 38.

    Genome Aggregation Database (gnomAD). Broad Institute (2025). Available online at: https://gnomad.broadinstitute.org/ (Accessed November 5, 2025).

  • 39.

    Bolze A Mendez F White S Tanudjaja F Isaksson M Jiang R et al A Catalog of Homoplasmic and Heteroplasmic Mitochondrial DNA Variants in Humans. BioRxiv (2020). 10.1101/798264

  • 40.

    Saha SK Saba AA Hasib M Rimon RA Hasan I Alam MS et al Evaluation of D-loop Hypervariable Region I Variations, Haplogroups and Copy Number of Mitochondrial DNA in Bangladeshi Population with Type 2 Diabetes. Heliyon (2021) 7:e07573. 10.1016/j.heliyon.2021.e07573

  • 41.

    Al-Ghamdi BA Al-Shamrani JM El-Shehawi AM Al-Johani I Al-Otaibi BG . Role of Mitochondrial DNA in Diabetes Mellitus Type I and Type II. Saudi J Biol Sci (2022) 29:103434. 10.1016/j.sjbs.2022.103434

  • 42.

    Jiang Z Zhang Y Yan J Li F Geng X Lu H et al De Novo Mutation of M.3243A>G Together with M.16093T>C Associated with Atypical Clinical Features in a Pedigree with MIDD Syndrome. J Diabetes Res (2019) 2019:5184647. 10.1155/2019/5184647

  • 43.

    Jiang W Li R Zhang Y Wang P Wu T Lin J et al Mitochondrial DNA Mutations Associated with Type 2 Diabetes Mellitus in Chinese Uyghur Population. Sci Rep (2017) 7:16989. 10.1038/s41598-017-17086-7

  • 44.

    Berdanier CD . Linking Mitochondrial Function to Diabetes Mellitus: An Animal’s Tale. Am J Physiol Cell Physiol (2007) 293:C8306. 10.1152/ajpcell.00227.2006

  • 45.

    Alwehaidah M Al-Kafaji G Bakhiet M Alfadhli S . Next-Generation Sequencing of the Whole Mitochondrial Genome Identifies Novel and Common Variants in Patients With Psoriasis, Type 2 Diabetes Mellitus and Psoriasis With Comorbid Type 2 Diabetes Mellitus. Biomed Rep (2021) 14:41. 10.3892/br.2021.1417

  • 46.

    Navaglia F Basso D Fogar P Sperti C Greco E Zambon C-F et al Mitochondrial DNA D-Loop in Pancreatic Cancer: Somatic Mutations Are Epiphenomena While the Germline 16519 T Variant Worsens Metabolism and Outcome. Am J Clin Pathol (2006) 126:593601. 10.1309/GQFCCJMH5KHNVX73

  • 47.

    Poulton J Luan J Macaulay V Hennings S Mitchell J Wareham NJ . Type 2 Diabetes Is Associated With a Common Mitochondrial Variant: Evidence From a Population-Based Case-Control Study. Hum Mol Genet (2002) 11:15813. 10.1093/hmg/11.13.1581

  • 48.

    Tang D-L Zhou X Li X Zhao L Liu F . Variation of Mitochondrial Gene and the Association With Type 2 Diabetes Mellitus in a Chinese Population. Diabetes Res Clin Pract (2006) 73:7782. 10.1016/j.diabres.2005.12.001

  • 49.

    Garcia-Gaona E García-Gregorio A García-Jiménez C López-Olaiz MA Mendoza-Ramírez P Fernandez-Guzman D et al Mtdna Single-Nucleotide Variants Associated With Type 2 Diabetes. Curr Issues Mol Biol (2023) 45:871632. 10.3390/cimb45110548

  • 50.

    Charoute H Kefi R Bounaceur S Benrahma H Reguig A Kandil M et al Novel Variants of Mitochondrial DNA Associated with Type 2 Diabetes Mellitus in Moroccan Population. Mitochondrial DNA A DNA Mapp Seq Anal (2018) 29:913. 10.1080/24701394.2016.1233530

  • 51.

    Janssen G Neu A ‘t Hart L van de Sande C Antonie MJ . Novel Mitochondrial DNA Length Variants and Genetic Instability in a Family With Diabetes and Deafness. Exp Clin Endocrinol Diabetes (2006) 114:16874. 10.1055/s-2006-924066

  • 52.

    Tawata M Ohtaka M Iwase E Ikegishi Y Aida K Onaya T . New Mitochondrial DNA Homoplasmic Mutations Associated With Japanese Patients With Type 2 Diabetes. Diabetes (1998) 47:2767. 10.2337/diab.47.2.276

  • 53.

    Khan IA Shaik NA Pasupuleti N Chava S Jahan P Hasan Q et al Screening of Mitochondrial Mutations and Insertion–Deletion Polymorphism in Gestational Diabetes Mellitus in the Asian Indian Population. Saudi J Biol Sci (2015) 22:2438. 10.1016/j.sjbs.2014.11.001

  • 54.

    Ding Y Zhang S Guo Q Zheng H . Mitochondrial Diabetes Is Associated With Trnaleu(Uur) A3243G and ND6 T14502C Mutations. Diabetes Metab Syndr Obes (2022) 15:1687701. 10.2147/DMSO.S363978

  • 55.

    Kadowaki T Kadowaki H Mori Y Tobe K Sakuta R Suzuki Y et al A Subtype of Diabetes Mellitus Associated With a Mutation of Mitochondrial DNA. N Engl J Med (1994) 330:9628. 10.1056/NEJM199404073301403

  • 56.

    Lin L Zhang D Jin Q Teng Y Yao X Zhao T et al Mutational Analysis of Mitochondrial Trna Genes in 200 Patients With Type 2 Diabetes Mellitus. Int J Gen Med (2021) 14:571935. 10.2147/IJGM.S330973

  • 57.

    Chen Y Liao WX Roy AC Loganath A Ng SC . Mitochondrial Gene Mutations in Gestational Diabetes Mellitus. Diabetes Res Clin Pract (2000) 48:2935. 10.1016/S0168-8227(99)00138-2

  • 58.

    Suzuki Y Suzuki S Hinokio Y Chiba M Atsumi Y Hosokawa K et al Diabetes Associated With a Novel 3264 Mitochondrial Trnaleu(Uur) Mutation. Diabetes Care (1997) 20:113840. 10.2337/diacare.20.7.1138

  • 59.

    Pranoto A . The Association of Mitochondrial DNA Mutation G3316A and T3394C with Diabetes Mellitus. Folia Med Indones (2005) 41:38.

  • 60.

    Lalrohlui F Thapa S Ghatak S Zohmingthanga J Senthil Kumar N . Mitochondrial Complex I and V Gene Polymorphisms in Type II Diabetes Mellitus Among High Risk Mizo-Mongoloid Population, Northeast India. Genes Environ (2016) 38:5. 10.1186/s41021-016-0034-z

  • 61.

    Yang L Guo Q Leng J Wang K Ding Y . Late Onset of Type 2 Diabetes Is Associated With Mitochondrial Trna Trp A5514G and Trna Ser(Agy) C12237T Mutations. J Clin Lab Anal (2022) 36:e24102. 10.1002/jcla.24102

  • 62.

    Li K Wu L Lin W Zhao T Qi Q Liu J et al Mutation at Position 5628 in the Mitochondrial Trnaala Gene in a Chinese Pedigree With Maternally Diabetes Mellitus. Res Square [Preprint] (2019). 10.21203/rs.2.17444/v1

  • 63.

    Li X Shang J Li S Wang Y . Identification of a Novel Mitochondrial Trna Mutation in Chinese Family with Type 2 Diabetes Mellitus. Pharmgenomics Pers Med (2024) 17:14961. 10.2147/PGPM.S438978

  • 64.

    Lalrohlui F Zohmingthanga J hruaii V Kumar NS . Genomic Profiling of Mitochondrial DNA Reveals Novel Complex Gene Mutations in Familial Type 2 Diabetes Mellitus Individuals from Mizo Ethnic Population, Northeast India. Mitochondrion (2020) 51:714. 10.1016/j.mito.2019.12.001

  • 65.

    Ding Y Zhang S Guo Q Leng J . Mitochondrial Diabetes Is Associated with the ND4 G11696A Mutation. Biomolecules (2023) 13:907. 10.3390/biom13060907

  • 66.

    Lynn S Wardell T Johnson MA Chinnery PF Daly ME Walker M et al Mitochondrial Diabetes: Investigation and Identification of a Novel Mutation. Diabetes (1998) 47:18002. 10.2337/diabetes.47.11.1800

  • 67.

    Wang M Liu H Zheng J Chen B Zhou M Fan W et al A deafness- and diabetes-associated Trna Mutation Causes Deficient Pseudouridinylation at Position 55 in Trnaglu and Mitochondrial Dysfunction. J Biol Chem (2016) 291:2102941. 10.1074/jbc.M116.739482

  • 68.

    Li K Wu L Liu J Lin W Qi Q Zhao T . Maternally Inherited Diabetes Mellitus Associated with a Novel m.15897G>A Mutation in Mitochondrial Trna Thr Gene. J Diabetes Res (2020) 2020:2057187. 10.1155/2020/2057187

  • 69.

    Miyamoto A Tomotaka U Takaaki K Kenichi M Chimi M . Molecular characterization of two pedigrees with maternally inherited diabetes mellitus. Mitochondrial DNA Part B (2022) 7:172431. 10.1080/23802359.2022.2050474

  • 70.

    Dabravolski SA Orekhova VA Baig MS Bezsonov EE Starodubova AV Popkova TV et al The Role of Mitochondrial Mutations and Chronic Inflammation in Diabetes. Int J Mol Sci (2021) 22:6733. 10.3390/ijms22136733

  • 71.

    Manwaring N Jones MM Wang JJ Rochtchina E Howard C Mitchell P et al Population Prevalence of the MELAS A3243G Mutation. Mitochondrion (2007) 7:2303. 10.1016/j.mito.2006.12.004

  • 72.

    Gorman GS Schaefer AM Ng Y Gomez N Blakely EL Alston CL et al Prevalence of Nuclear and Mitochondrial DNA Mutations Related to Adult Mitochondrial Disease. Ann Neurol (2015) 77:7539. 10.1002/ana.24362

  • 73.

    Goto Y Nonaka I Horai S . A Mutation in the Trnaleu (UUR) Gene Associated with the MELAS Subgroup of Mitochondrial Encephalomyopathies. Nature (1990) 348:6513. 10.1038/348651a0

  • 74.

    Rahmadanthi FR Maksum IP . Transfer RNA Mutation Associated with Type 2 Diabetes Mellitus. Biology (Basel) (2023) 12:871. 10.3390/biology12060871

  • 75.

    Hao R Yao Y-N Zheng Y-G Xu M-G Wang E-D . Reduction of Mitochondrial Trna Leu (UUR) Aminoacylation by Some Melas‐Associated Mutations. FEBS Lett (2004) 578:1359. 10.1016/j.febslet.2004.11.004

  • 76.

    Peschansky VJ Wahlestedt C . Non-Coding Rnas as Direct and Indirect Modulators of Epigenetic Regulation. Epigenetics (2014) 9:312. 10.4161/epi.27473

  • 77.

    Low HC Chilian WM Ratnam W Karupaiah T Md Noh MF Mansor F et al Changes in Mitochondrial Epigenome in Type 2 Diabetes Mellitus. Br J Biomed Sci (2023) 80:10884. 10.3389/bjbs.2023.10884

  • 78.

    Liu R Wu J Guo H Yao W Li S Lu Y et al Post‐Translational Modifications of Histones: Mechanisms, Biological Functions, and Therapeutic Targets. MedComm (2023) 4:e292. 10.1002/mco2.292

  • 79.

    Gibney ER Nolan CM . Epigenetics and Gene Expression. Heredity (Edinb) (2010) 105:413. 10.1038/hdy.2010.54

  • 80.

    Moosavi A Motevalizadeh Ardekani A . Role of Epigenetics in Biology and Human Diseases. Iran Biomed J (2016) 20:24658. 10.22045/ibj.2016.01

  • 81.

    Manev H Dzitoyeva S . Progress in Mitochondrial Epigenetics. Biomol Concepts (2013) 4:3819. 10.1515/bmc-2013-0005

  • 82.

    Coppedè F Stoccoro A . Mitoepigenetics and Neurodegenerative Diseases. Front Endocrinol (Lausanne) (2019) 10:86. 10.3389/fendo.2019.00086

  • 83.

    Hong EE Okitsu CY Smith AD Hsieh C-L . Regionally Specific and Genome-wide Analyses Conclusively Demonstrate the Absence of Cpg Methylation in Human Mitochondrial DNA. Mol Cell Biol (2013) 33:268390. 10.1128/MCB.00220-13

  • 84.

    Saini SK Mangalhara KC Prakasam G Bamezai RNK . DNA methyltransferase1 (DNMT1) isoform3 Methylates Mitochondrial Genome and Modulates Its Biology. Sci Rep (2017) 7:1525. 10.1038/s41598-017-01743-y

  • 85.

    Bellizzi D D’Aquila P Scafone T Giordano M Riso V Riccio A et al The Control Region of Mitochondrial DNA Shows an Unusual Cpg and Non-cpg Methylation Pattern. DNA Res (2013) 20:53747. 10.1093/dnares/dst029

  • 86.

    Mechta M Ingerslev LR Fabre O Picard M Barrès R . Evidence Suggesting Absence of Mitochondrial DNA Methylation. Front Genet (2017) 8:166. 10.3389/fgene.2017.00166

  • 87.

    Hao Z Wu T Cui X Zhu P Tan C Dou X et al N 6-deoxyadenosine Methylation in Mammalian Mitochondrial DNA. Mol Cell (2020) 78:38295.e8. 10.1016/j.molcel.2020.02.018

  • 88.

    Li X Zhang Z Luo X Schrier J Yang AD Wu TP . The Exploration of N6-deoxyadenosine Methylation in Mammalian Genomes. Protein Cell (2021) 12:75668. 10.1007/s13238-021-00866-3

  • 89.

    Koh CWQ Goh YT Toh JDW Neo SP Ng SB Gunaratne J et al Single-Nucleotide-Resolution Sequencing of Human N 6-methyldeoxyadenosine Reveals strand-asymmetric Clusters Associated with SSBP1 on the Mitochondrial Genome. Nucleic Acids Res (2018) 46:1165970. 10.1093/nar/gky1104

  • 90.

    Sharma N Pasala MS Prakash A . Mitochondrial DNA: Epigenetics and Environment. Environ Mol Mutagen (2019) 60:66882. 10.1002/em.22319

  • 91.

    Zhang F Zhang L Hu G Chen X Liu H Li C et al Rectifying METTL4-mediated N 6 -methyladenine Excess in Mitochondrial DNA Alleviates Heart Failure. Circulation (2024) 150:144158. 10.1161/CIRCULATIONAHA.123.068358

  • 92.

    Dostal V Churchill MEA . Cytosine Methylation of Mitochondrial DNA at Cpg Sequences Impacts Transcription Factor A DNA Binding and Transcription. Biochim Biophys Acta Gene Regul Mech (2019) 1862:598607. 10.1016/j.bbagrm.2019.01.006

  • 93.

    Patil V Cuenin C Chung F Aguilera JRR Fernandez-Jimenez N Romero-Garmendia I et al Human Mitochondrial DNA Is Extensively Methylated in a Non-cpg Context. Nucleic Acids Res (2019) 47:1007285. 10.1093/nar/gkz762

  • 94.

    Dou X Boyd-Kirkup JD McDermott J Zhang X Li F Rong B et al The strand-biased Mitochondrial DNA Methylome and Its Regulation by DNMT3A. Genome Res (2019) 29:162234. 10.1101/gr.234021.117

  • 95.

    Cao K Lv W Wang X Dong S Liu X Yang T et al Hypermethylation of Hepatic Mitochondrial ND6 Provokes Systemic Insulin Resistance. Adv Sci (2021) 8:2004507. 10.1002/advs.202004507

  • 96.

    Lüth T Wasner K Klein C Schaake S Tse R Pereira SL et al Nanopore single-molecule Sequencing for Mitochondrial DNA Methylation Analysis: Investigating parkin-associated Parkinsonism as a Proof of Concept. Front Aging Neurosci (2021) 13:713084. 10.3389/fnagi.2021.713084

  • 97.

    Yue Y Ren L Zhang C Miao K Tan K Yang Q et al Mitochondrial Genome Undergoes De Novo DNA Methylation that Protects Mtdna Against Oxidative Damage During the peri-implantation Window. Proc Natl Acad Sci USA (2022) 119:e2201168119. 10.1073/pnas.2201168119

  • 98.

    Zhang Z Huang Q Zhao D Lian F Li X Qi W . The Impact of Oxidative stress-induced Mitochondrial Dysfunction on Diabetic Microvascular Complications. Front Endocrinol (Lausanne) (2023) 14:1112363. 10.3389/fendo.2023.1112363

  • 99.

    Mishra M Kowluru RA . Epigenetic Modification of Mitochondrial DNA in the Development of Diabetic Retinopathy. Invest Ophthalmol Vis Sci (2015) 56:513342. 10.1167/iovs.15-16937

  • 100.

    Kowluru RA . Retinopathy in a diet-induced Type 2 Diabetic Rat Model and Role of Epigenetic Modifications. Diabetes (2020) 69:68998. 10.2337/db19-1009

  • 101.

    Bordoni L Smerilli V Nasuti C Gabbianelli R . Mitochondrial DNA Methylation and Copy Number Predict Body Composition in a Young Female Population. J Transl Med (2019) 17:399. 10.1186/s12967-019-02150-9

  • 102.

    Zheng LD Linarelli LE Brooke J Smith C Wall SS Greenawald MH et al Mitochondrial Epigenetic Changes Link to Increased Diabetes Risk and early-stage Prediabetes Indicator. Oxid Med Cell Longev (2016) 2016:529063810. 10.1155/2016/5290638

  • 103.

    Zheng LD Linarelli LE Liu L Wall SS Greenawald MH Seidel RW et al Insulin Resistance Is Associated with Epigenetic and Genetic Regulation of Mitochondrial DNA in Obese Humans. Clin Epigenetics (2015) 7:60. 10.1186/s13148-015-0093-1

  • 104.

    Anstee QM McPherson S Day CP . How Big a Problem Is Non-alcoholic Fatty Liver Disease?BMJ (2011) 343:d3897. 10.1136/bmj.d3897

  • 105.

    Loomba R Abraham M Unalp A Wilson L Lavine J Doo E et al Association Between Diabetes, Family History of Diabetes, and Risk of Nonalcoholic Steatohepatitis and Fibrosis. Hepatology (2012) 56:94351. 10.1002/hep.25772

  • 106.

    Pirola CJ Gianotti TF Burgueño AL Rey-Funes M Loidl CF Mallardi P et al Epigenetic Modification of Liver Mitochondrial DNA Is Associated with Histological Severity of Nonalcoholic Fatty Liver Disease. Gut (2013) 62:135663. 10.1136/gutjnl-2012-302962

  • 107.

    Shi Y Zhang H Huang S Yin L Wang F Luo P et al Epigenetic Regulation in Cardiovascular Disease: Mechanisms and Advances in Clinical Trials. Signal Transduct Target Ther (2022) 7:200. 10.1038/s41392-022-01055-2

  • 108.

    Woischnik M Moraes CT . Pattern of Organization of Human Mitochondrial Pseudogenes in the Nuclear Genome. Genome Res (2002) 12:88593. 10.1101/gr.227202

  • 109.

    Milián-García Y Hempel CA Janke LAA Young RG Furukawa-Stoffer T Ambagala A et al Mitochondrial Genome Sequencing, Mapping, and Assembly Benchmarking for Culicoides Species (Diptera: Ceratopogonidae). BMC Genomics (2022) 23:584. 10.1186/s12864-022-08743-x

  • 110.

    Liao P-C Bergamini C Fato R Pon LA Pallotti F . Isolation of Mitochondria from Cells and Tissues. Methods Cell Biol (2020) 2(155):331. 10.1016/bs.mcb.2019.10.002

  • 111.

    Repolês BM Gorospe CM Tran P Nilsson AK Wanrooij PH . The Integrity and Assay Performance of Tissue Mitochondrial DNA Is Considerably Affected by Choice of Isolation Method. Mitochondrion (2021) 61:17987. 10.1016/j.mito.2021.10.005

  • 112.

    Quispe-Tintaya W White RR Popov VN Vijg J Maslov AY . Fast Mitochondrial DNA Isolation from Mammalian Cells for next-generation Sequencing. Biotechniques (2013) 55:1336. 10.2144/000114077

  • 113.

    Cheng C Fei Z Xiao P . Methods to Improve the Accuracy of next-generation Sequencing. Front Bioeng Biotechnol (2023) 11:982111. 10.3389/fbioe.2023.982111

  • 114.

    Yu H Hahn Y Yang I . Reference Materials for Calibration of Analytical Biases in Quantification of DNA Methylation. PLoS One (2015) 10:e0137006. 10.1371/journal.pone.0137006

  • 115.

    Mohammadi MM Bavi O . DNA Sequencing: An Overview of Solid-State and Biological Nanopore-based Methods. Biophys Rev (2022) 14:99110. 10.1007/s12551-021-00857-y

  • 116.

    Victoria Wang X Blades N Ding J Sultana R Parmigiani G . Estimation of Sequencing Error Rates in Short Reads. BMC Bioinformatics (2012) 13:185. 10.1186/1471-2105-13-185

  • 117.

    Hoff KJ . The Effect of Sequencing Errors on Metagenomic Gene Prediction. BMC Genomics (2009) 10:520. 10.1186/1471-2164-10-520

  • 118.

    Ronchi D Garone C Bordoni A Gutierrez RP Calvo SE Ripolone M et al Next-Generation Sequencing Reveals DGUOK Mutations in Adult Patients with Mitochondrial DNA Multiple Deletions. Brain (2012) 135:340415. 10.1093/brain/aws258

  • 119.

    Rieber N Zapatka M Lasitschka B Jones D Northcott P Hutter B et al Coverage Bias and Sensitivity of Variant Calling for Four whole-genome Sequencing Technologies. PLoS One (2013) 8:e66621. 10.1371/journal.pone.0066621

  • 120.

    van Dijk EL Auger H Jaszczyszyn Y Thermes C . Ten Years of next-generation Sequencing Technology. Trends Genet (2014) 30:41826. 10.1016/j.tig.2014.07.001

  • 121.

    Mascher M Wu S Amand PS Stein N Poland J . Application of Genotyping-By-Sequencing on Semiconductor Sequencing Platforms: A Comparison of Genetic and Reference-Based Marker Ordering in Barley. PLoS One (2013) 8:e76925. 10.1371/journal.pone.0076925

  • 122.

    Goodwin S McPherson JD McCombie WR . Coming of Age: Ten Years of next-generation Sequencing Technologies. Nat Rev Genet (2016) 17:33351. 10.1038/nrg.2016.49

  • 123.

    Donath X Saint-Martin C Dubois-Laforgue D Rajasingham R Mifsud F Ciangura C et al Next-Generation Sequencing Identifies Monogenic Diabetes in 16% of Patients with Late Adolescence/Adult-Onset Diabetes Selected on a Clinical Basis: A Cross-Sectional Analysis. BMC Med (2019) 17:132. 10.1186/s12916-019-1363-0

  • 124.

    Dai Q Ye C Irkliyenko I Wang Y Sun H-L Gao Y et al Ultrafast Bisulfite Sequencing Detection of 5-methylcytosine in DNA and RNA. Nat Biotechnol (2024) 42:155970. 10.1038/s41587-023-02034-w

  • 125.

    Krehenwinkel H Wolf M Lim JY Rominger AJ Simison WB Gillespie RG . Estimating and Mitigating Amplification Bias in Qualitative and Quantitative Arthropod Metabarcoding. Sci Rep (2017) 7:17668. 10.1038/s41598-017-17333-x

  • 126.

    Mechta M Ingerslev LR Barrès R . Methodology for Accurate Detection of Mitochondrial DNA Methylation. J Vis Exp (2018) 135:e57772. 10.3791/57772

  • 127.

    Devall M Soanes DM Smith AR Dempster EL Smith RG Burrage J et al Genome-Wide Characterization of Mitochondrial DNA Methylation in Human Brain. Front Endocrinol (Lausanne) (2022) 13:1059120. 10.3389/fendo.2022.1059120

  • 128.

    Guitton R Dölle C Alves G Ole-Bjørn T Nido GS Tzoulis C . Ultra-Deep Whole Genome Bisulfite Sequencing Reveals a Single Methylation Hotspot in Human Brain Mitochondrial DNA. Epigenetics (2022) 17:90621. 10.1080/15592294.2022.2045754

  • 129.

    Aminuddin A Ng PY Leong C-O Chua EW . Mitochondrial DNA Alterations May Influence the Cisplatin Responsiveness of Oral Squamous Cell Carcinoma. Sci Rep (2020) 10:7885. 10.1038/s41598-020-64664-3

  • 130.

    Bicci I Calabrese C Golder ZJ Gomez-Duran A Chinnery PF . Oxford Nanopore Sequencing-based Protocol to Detect Cpg Methylation in Human Mitochondrial DNA (2021). 10.1101/2021.02.20.432086

  • 131.

    Goldsmith C Rodríguez-Aguilera JR El-Rifai I Jarretier-Yuste A Hervieu V Raineteau O et al Low Biological Fluctuation of Mitochondrial Cpg and Non-cpg Methylation at the single-molecule Level. Sci Rep (2021) 11:8032. 10.1038/s41598-021-87457-8

  • 132.

    Baccarelli AA Byun H-M . Platelet Mitochondrial DNA Methylation: A Potential New Marker of Cardiovascular Disease. Clin Epigenetics (2015) 7:44. 10.1186/s13148-015-0078-0

  • 133.

    Liu B Du Q Chen L Fu G Li S Fu L et al Cpg Methylation Patterns of Human Mitochondrial DNA. Sci Rep (2016) 6:23421. 10.1038/srep23421

  • 134.

    Mposhi A Cortés-Mancera F Heegsma J de Meijer VE van de Sluis B Sydor S et al Mitochondrial DNA Methylation in Metabolic Associated Fatty Liver Disease. Front Nutr (2023) 10:964337. 10.3389/fnut.2023.964337

  • 135.

    Sturm Á Sharma H Bodnár F Aslam M Kovács T Németh Á et al N 6-methyladenine Progressively Accumulates in Mitochondrial DNA During Aging. Int J Mol Sci (2023) 24:14858. 10.3390/ijms241914858

  • 136.

    Rauluseviciute I Drabløs F Rye MB . DNA Methylation Data by Sequencing: Experimental Approaches and Recommendations for Tools and Pipelines for Data Analysis. Clin Epigenetics (2019) 11:193. 10.1186/s13148-019-0795-x

  • 137.

    Delahaye C Nicolas J . Sequencing DNA with Nanopores: Troubles and Biases. PLoS One (2021) 16:e0257521. 10.1371/journal.pone.0257521

  • 138.

    Tabor HK Berkman BE Hull SC Bamshad MJ . Genomics Really Gets Personal: How Exome and Whole Genome Sequencing Challenge the Ethical Framework of Human Genetics Research. Am J Med Genet A (2011) 155:291624. 10.1002/ajmg.a.34357

  • 139.

    Martinez-Martin N Magnus D . Privacy and Ethical Challenges in next-generation Sequencing. Expert Rev Precis Med Drug Dev (2019) 4:95104. 10.1080/23808993.2019.1599685

  • 140.

    Turnwald BP Goyer JP Boles DZ Silder A Delp SL Crum AJ . Learning One’s Genetic Risk Changes Physiology Independent of Actual Genetic Risk. Nat Hum Behav (2018) 3:4856. 10.1038/s41562-018-0483-4

  • 141.

    Knoppers BM Zawati MH Sénécal K . Return of Genetic Testing Results in the Era of whole-genome Sequencing. Nat Rev Genet (2015) 16:5539. 10.1038/nrg3960

  • 142.

    Saxena N Taneja N Shome P Mani S . Mitochondrial Donation: A Boon or Curse for the Treatment of Incurable Mitochondrial Diseases. J Hum Reprod Sci (2018) 11:39. 10.4103/jhrs.JHRS_54_17

Summary

Keywords

ethical limitations, haploid, methylation, mitochondrial dysfunction, next-generation sequencing

Citation

Koh MX, Simpson T, Zain SM, Ayub Q, Cheah HL, Pan Y, Cheng SH and Pung Y-F (2025) Mitochondrial DNA Mutations and Epigenetic Regulation in Type 2 Diabetes Mellitus Development. Br. J. Biomed. Sci. 82:15375. doi: 10.3389/bjbs.2025.15375

Received

04 August 2025

Revised

07 November 2025

Accepted

17 November 2025

Published

27 November 2025

Volume

82 - 2025

Updates

Copyright

*Correspondence: Yuh-Fen Pung,

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

Outline

Figures

Cite article

Copy to clipboard


Export citation file


Share article