ITPR1 and spinocerebellar ataxia type 15/16: spinocerebellar ataxia 15 (SCA15) and spinocerebellar ataxia 16 (SCA16) in humans and in mice are caused by deletion and missense mutations in the gene for inositol-1,4,5-trisphosphate receptor type 1 (IP3R1), a calcium channel on the sER (Desaiah et al., 1991; Street et al., 1997; Zecevic et al., 1999; Lin et al., 2000; Storey et al., 2001; Serra et al., 2004; van de Leemput et al., 2007; Chen et al., 2008; Chou et al., 2008; Hara et al., 2008; Iwaki et al., 2008; Liu et al., 2009; Di Gregorio et al., 2010; Novak et al., 2010a,b; Huang et al., 2012).