SIRT1 and spinocerebellar ataxia 7: Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant disorder characterized by progressive cerebellar degeneration and motor incoordination, and elevated levels of PAR were observed in cerebellar neurons of SCA7 patients.63 In SCA7 mouse models, NAD+ depletion was responsible for dysregulation of Sirt1, a NAD+ -dependent deacetylase.