COQ2 and multiple system atrophy: Furthermore, the activity of COQ2 in lymphoblastoid cell lines with the COQ2 variant p.V393A, established from patients with MSA, was significantly lower than that in control cell lines, and the level of coenzyme Q10 activity in frozen cerebellum samples obtained from a patient carrying a homozygous mutation was substantially lower than the levels observed in controls without the mutation12.