ITPR1 and cerebellar ataxia: Loss of IP3R function in the vertebrate nervous system leads to defects in motor coordination and spino-cerebellar ataxia (SCA); a deletion mutation of ITPR1 in human causes SCA15/16 (van de Leemput et al., 2007; Novak et al., 2010), and the mouse knock out (KO) for Itpr1 displays ataxia (Matsumoto et al., 1996).