Dysfunction of the mitochondrial respiratory chain may also contribute to the pathophysiology of MSA, as suggested by the evidence that variants in the COQ2 gene that reduce the function of parahydroxybenxzoate-polyprenyltransferase (an enzyme necessary for the biosynthesis of coenzyme Q10) are associated with an increased risk of developing MSA [38]. The gene discussed is COQ2; the disease is multiple system atrophy.