Relationship between mitochondrial DNA A10398G polymorphism and Parkinson's disease: a meta-analysis

Mitochondrial DNA variants, haplogroups and risk of Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

Growing evidence has shown that mitochondrial dysfunction is part of the pathogenesis of Parkinson's disease (PD). However, the role of mitochondrial DNA (mtDNA) variants on PD onset is unclear.

OBJECTIVES

The present study aims to evaluate the effect of mtDNA variants and haplogroups on risk of developing PD.

METHODS

Systematic review and meta-analysis of studies investigating associations between PD and mtDNA variants and haplogroups.

RESULTS

A total of 33 studies were eligible from 957 screened studies. Among 13,640 people with PD and 22,588 control individuals, the association with PD was consistently explored in 13 mtDNA variants in 10 genes and 19 macrohaplogroups. Four mtDNA variants were associated with PD: m.4336C (odds ratio [OR] = 2.99; 95 % confidence interval [CI] = 1.79-5.02), m.7028T (OR = 0.80; 95 % CI = 0.70-0.91), m.10398G (OR = 0.92; 95 % CI = 0.85-0.98), and m.13368A (OR = 0.74; 95 % CI = 0.56-0.98). Four mtDNA macrohaplogroups were associated with PD: R (OR = 2.25; 95 % CI = 1.92-2.65), F (OR = 1.18; 95 % CI = 1.01-1.38), H (OR = 1.12; 95 % CI = 1.06-1.18), and B (OR = 0.77; 95 % CI = 0.65-0.92).

CONCLUSIONS

Despite most studies may be underpowered by the underrepresentation of people without dominant European- and Asian-ancestry, low use of next-generation sequencing for genotyping and small sample sizes, the identification of mtDNA variants and macrohaplogroups associated with PD strengthens the link between the disease and mitochondrial dysfunction and mtDNA genomic instability.

Role of mitochondria DNA A10398G polymorphism on development of Parkinson's disease: A PRISMA-compliant meta-analysis

BACKGROUND

Parkinson's disease (PD) is characterized by memory loss and multiple cognitive disorders caused primarily by neurodegeneration. However, the preventative effects of the mitochondrial A10398G DNA polymorphism remain controversial. This meta-analysis comprehensively assessed evidence on the influence of the mitochondrial DNA A10398G variant on PD development.

METHODS

The PubMed, EMBASE, EBSCO, Springer Link, and Web of Science databases were searched from inception to May 31, 2020. We used a pooled model with random effects to explore the effect of A10398G on the development of PD. Stata MP version 14.0 was used to calculate the odds ratios and 95% confidence intervals (CIs) from the eligible studies to assess the impact of mitochondrial DNA A10398G on PD development.

RESULTS

The overall survey of the populations showed no significant association between mitochondrial DNA A10398G polymorphism (G allele compared to A allele) and PD (odds ratio = 0.85, 95% CI = 0.70-1.04, p = 0.111); however, a significant association between the mutation and PD was observed in the Caucasian population (odds ratio = 0.71, 95% CI = 0.58-0.87, p = 0.001). A neutral effect was observed in the Asian population (odds ratio = 1.10, 95% CI = 0.94-1.28, p = 0.242).

CONCLUSIONS

The results of this meta-analysis showed the potential protective effect of the mitochondrial DNA A10398G polymorphism on the risk of developing PD in the Caucasian population. Studies with better designs and larger samples with intensive work are required to validate these results.

Biocomplexity and Fractality in the Search of Biomarkers of Aging and Pathology: Mitochondrial DNA Profiling of Parkinson's Disease

Increasing evidence implicates mitochondrial dysfunction in the etiology of Parkinson's disease (PD). Mitochondrial DNA (mtDNA) mutations are considered a possible cause and this mechanism might be shared with the aging process and with other age-related neurodegenerative disorders such as Alzheimer's disease (AD). We have recently proposed a computerized method for mutated mtDNA characterization able to discriminate between AD and aging. The present study deals with mtDNA mutation-based profiling of PD. Peripheral blood mtDNA sequences from late-onset PD patients and age-matched controls were analyzed and compared to the revised Cambridge Reference Sequence (rCRS). The chaos game representation (CGR) method, modified to visualize heteroplasmic mutations, was used to display fractal properties of mtDNA sequences and fractal lacunarity analysis was applied to quantitatively characterize PD based on mtDNA mutations. Parameter β, from the hyperbola model function of our lacunarity method, was statistically different between PD and control groups when comparing mtDNA sequence frames corresponding to GenBank np 5713-9713. Our original method, based on CGR and lacunarity analysis, represents a useful tool to analyze mtDNA mutations. Lacunarity parameter β is able to characterize individual mutation profile of mitochondrial genome and could represent a promising index to discriminate between PD and aging.

Analysis of mitochondrial DNA allelic changes in Parkinson's disease: a preliminary study

BACKGROUND

Mitochondrial DNA (mtDNA) mutations are considered as a possible primary cause of age-associated neurodegenerative disorders like Parkinson's disease (PD).

AIMS

To analyze, along the whole mtDNA sequence of PD patients, the presence of non-reference alleles compared to reference alleles, as defined in the revised Cambridge Reference Sequence (rCRS).

METHODS

mtDNA was extracted from whole blood of PD and control groups, and was sequenced using a chip-based resequencing system.

RESULTS

58 nucleotide positions (np) exhibited a different allelic distribution in the two groups; in 81% of them the non-reference alleles were over-represented in PD patients, similar to findings reported in patients with Alzheimer's disease, albeit in reduced proportion. Closer analysis of the 58 np in PD group showed that they were characterized by low-level heteroplasmy, and that the nucleotide substitutions determined an amino acid change in 84% of cases.

CONCLUSIONS

These results suggest that mtDNA allelic changes are increased in PD and that age-related neurodegenerative diseases could share a common mechanism involving mtDNA.