Ionic balance defects like: mechanosensory protein (PIEZO1) and the Gardos channel (KCNN4) defects are associated with dehydrated hereditary stomatocytosis 1 and 2, respectively; Rh-associated glycoprotein (RhAG) defects with overhydrated stomatocytosis; anion transporter (SLC4A1) defects with increased permeability to cations at low temperatures; adenosine triphosphate-binding cassette family member (ABCB6) defects with familial pseudohyperkalamia while glucose transporter(GLUT1) defects manifest with mental retardation, seizures, hepatosplenomegaly and cryohydrocytosis (20, 21, 22). The gene discussed is KCNN4; the disease is overhydrated hereditary stomatocytosis.