ATXN3 and autosomal dominant cerebellar ataxia: There are currently six described polyQ SCAs, SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17, with the number denoting the timeline in which the diseases were first discovered (Table 1)—SCA1 was the first described SCA disease, SCA2 the second, etc. The polyQ SCAs are all caused by a variable CAG expansion located within the coding region of their respective genes; this expansion directly causes the inclusion of an extended polyQ tract in the encoded proteins, leading to conformational changes giving the proteins a toxic gain of function [7].