The Orr laboratory identified cholecystokinin (CCK) as greatly reduced in SCA1 mouse models and subsequently also in ATXN2[Q127] mice.48 Treatment of SCA1 and SCA2 mouse models with the Cck-receptor-1 agonist A71623 improved phenotypes in both mouse models. This evidence concerns the gene CCK and spinocerebellar ataxia type 2.