COQ2 and multiple system atrophy: Although the role of the COQ2 variants as a cause of MSA is yet to be replicated, the specific and significant decrease of CoQ10 in the cerebellar cortex of the MSA cohort, but not of cerebellar ataxias (CRB_ATX), suggests that a perturbation in the CoQ10 biosynthetic pathway might be involved in the pathogenesis of MSA.