KCNMA1 and autosomal dominant cerebellar ataxia: Likewise, an increase in inclusion of exon 23b in Kcnma1 in SCA cerebellum leads to an incomplete calcium bowl, a region within the RCK2 domain, which impairs Ca2+ binding, reduces channel activation and K+ efflux—in turn, slowing synapse repolarization77,78 (Fig. 7D).