The hereditary stomatocytoses and allied disorders: congenital disorders of erythrocyte membrane permeability to Na and K

The hereditary stomatocytoses and allied disorders are a set of dominantly inherited haemolytic anaemias in which the plasma membrane of the red cell 'leaks' sodium and potassium. There are about 10 different forms of these c onditions, ranging from a moderately severe haemolytic anaemia to minor con ditions in which the haematology is essentially normal, but where the patie nts present with pseudohyperkalaemia, due to leakage of K from the red cell s on cooling to room temperature. Frequently misdiagnosed as atypical hered itary spherocytosis, these conditions can show marked thrombotic complicati ons after splenectomy, which should be avoided. Laboratory studies of these conditions have drawn attention to a 32 kDa membrane protein, stomatin, wh ich seems to act as a regulator of Na and K transport in human and animal t issues generally, but mutations in this gene do not cause these diseases, G enetic mapping in some kindreds, but not all, points to a mutation locus on chromosome 16.