ITPR1 and spinocerebellar ataxia type 15/16: In case of the gene encoding IP3R type 1 (IP3R1, encoded by ITPR1), loss-of-function mutations result in spinocerebellar ataxia types 15 and 29 (SCA15 and SCA29, respectively), Gillespie syndrome, and sporadic infantile-onset cerebellar ataxia [41,42,43,44,45,46].