Mutations in Kir4.1 typically affect the function of both homomeric Kir4.1 (Bockenhauer et al., 2009) as well as heteromeric Kir4.1/Kir5.1 (Reichold et al., 2010) channels, although there are some interesting exceptions to this rule (see section “Autism,” Table 1). This evidence concerns the gene KCNJ10 and autism.