MtDNA variations and haplogroups could be one of the contributory factors to explain the remaining heterogeneity in FRDA, since mitochondrial oxidative stress is thought to be involved in the pathogenesis of FRDA. A significantly higher load of overall mitochondrial variations (with a trend toward the coding region) per individual was noted among FRDA cases rather than controls (p-value<0.03). A non-synonymous variation (p. L237M) in ND2 was over-represented among FRDA cases (p-value 0.04). This variation has a reported association with longevity and myocardial infarction. We also observed over-representation of H haplogroup (Caucasian mitochondrial haplogroup) among FRDA patients. We have not observed the influence of mitochondrial variations and haplogroup upon age at onset of FRDA. Overall, this study identifies the functionally important variations and mitochondrial lineage of Indian FRDA cases and, that underscores the importance of studying the role of mitochondrial genome variations in FRDA.

Read more: Investigation of mitochondrial DNA variations among Indian Friedreich's ataxia (FRDA) patients