ATXN3 and Kennedy disease: To date, nine types of polyQ diseases have been found: Huntington's disease (HD), spinobulbar muscular atrophy (SBMA), dentatorubral‐pallidoluysian atrophy, spinocerebellar ataxia type 1 (SCA1), SCA2, SCA3, SCA6, SCA7 and SCA17.2