So far, only one family with adult-onset SCA has been reported to harbor a missense mutation in ITPR1[13] and the Ca2+ release properties of this mutant ITPR1 are comparable with wild type ITPR1: therefore, functional pathogenicity of this change has not been established or there is another mechanism for the disease process[22]. This evidence concerns the gene ITPR1 and autosomal dominant cerebellar ataxia.