SAO and CHC are caused by variants of SLC4A1, the gene encoding band 3 [anion exchanger 1 (AE1)], and have a cation leak of about four times normal (Tanner et al., 1991; Bruce et al., 1999, 2005; Guizouarn et al., 2011). The gene discussed is SLC4A1; the disease is cryohydrocytosis.