SLC4A1 and hereditary elliptocytosis: The cryohydrocytosis phenotype, including South-east Asian Ovalocytosis, results from mutations in SLC4A1, and the very rare condition, stomatin-deficient cryohydrocytosis, is caused by mutations in SLC2A1. Mutations in RHAG cause the very leaky condition over-hydrated stomatocytosis, and mutations in ABCB6 result in familial pseudohyperkalemia.