ITPR1 and cerebellar ataxia: Mutations localized in the coupling/regulatory domain of IP3R1, such as ITPR1 p.P1068L (originally annotated as p.P1059L, reference sequence NM_002222 [6]), might affect the binding affinity and transmission of the IP3 signaling which further disrupts the calcium influx, resulting in cerebellar ataxia [11].