Two different heterozygous mutations in the ITPR1 gene, a 4657G-A transition resulting in a val1553-to-met (V1553M) substitution and a heterozygous 1804G-A transition in the ITPR1 gene resulting in an asn602-to-asp (N602D) substitution, respectively, have recently been found to underlie SCA29 in two affected families [133]. The gene discussed is ITPR1; the disease is spinocerebellar ataxia type 29.