ATXN1 and spinocerebellar ataxia type 1: Knockout studies (KO) in mice have demonstrated that Pum1 haploinsufficiency (complete knockout dies at the pre-implantation stage [44]) causes progressive motor dysfunction and spinocerebellar ataxia type 1 (SCA1)-like neurodegeneration with motor impairment, primarily by increasing Ataxin1 (ATXN1) levels (a protein that accumulates in neurons and exerts neurotoxicity) [45].