Investigation of the correlation between mildly deleterious mtDNA Variations and the clinical progression of multiple sclerosis.

Abstract Background Evidence suggests that mitochondrial DNA (mtDNA) variation at a population level may influence susceptibility to, or the clinical progression of Multiple Sclerosis (MS). Objective To determine if mtDNA population variation is linked to the clinical progress of MS. Methods Using the complete mtDNA sequences of 217 MS patients, we applied the new ‘variant load’ model, designed as a framework by which to examine the role of mtDNA variation in the context of complex clinical disease. Results No significant association was detected between mtDNA ‘variant load’and the clinical measures of progression. Conclusion Our results suggest that mtDNA population variation does not play a substantial role in the clinical progression of MS; however, modest effects and/or effects in a subgroup of patients cannot be entirely excluded. Results do not exclude the possibility of detecting an association between variation and more strictly quantified variables obtained from histopathologically-stained specimens. The results further illustrate the method's applicabilityto other disease phenotypes.