Polymorphisms of genes required for methionine synthesis and DNA methylation influence mitochondrial DNA methylation.

Impaired methylation of the mitochondrial DNA and particularly in the regulatory displacement loop (D-loop) region, is increasingly observed in patients with neurodegenerative disorders. The present study aims to investigate if common polymorphisms of genes required for one-carbon metabolism ( and ) and DNA methylation reactions ( and ) influence D-loop methylation levels. D-loop methylation data were available from 133 late-onset Alzheimer's disease patients and 130 matched controls. Genotyping was performed with PCR-RFLP or high resolution melting techniques. Both 66A > G and -448A > G polymorphisms were significantly associated with D-loop methylation levels. This exploratory study suggests that and polymorphisms influence mitochondrial DNA methylation; further research is required to better address this issue.