ITPR1 and spinocerebellar ataxia type 29: Heterozygous pathogenic variants of ITPR1 have been associated with a broad clinical spectrum, ranging from adult-onset Spinocerebellar Ataxia type 15 (SCA15) to early-onset Spinocerebellar Ataxia type 29 (SCA29) and Gillespie syndrome, while homozygous variants have been described only in the early onset form [3].