ATXN3 and MERRF: As for diagnostic studies, the study by Arcuria et al., the largest one [31], enrolled 87 patients affected by FA (n = 36), SCA1 (n = 9), SCA2 (n = 6), myoclonic epilepsy with ragged red fibers (MERRF) (n = 3), SCA3 (n = 2), SCA8 (n = 2), autosomal-recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) (n = 1), autosomal-recessive ataxia type 8 (SCAR8) (n = 1), multiple system atrophy-cerebellar type (MSA-C) (n = 1), or CA with no defined genetic diagnosis (n = 26), as well as 170 sex- and age-matched healthy subjects.