ATXN1 and spinocerebellar ataxia type 1: ATXN1 is the cause of spino-cerebellar ataxia type 1 (SCA1, OMIM:164400), a dominantly inherited neurodegenerative disease, through CAG repeat expansion with a gain-of-function mechanism [7], while loss-of-function of ATXN1 seems to lead to motor coordination impairments and learning deficits [8].