Familial hyperpotassemia and hypertension accompanied by normal plasma aldosterone levels: possible hereditary cell membrane defect

Abstract

Hypertension and hyperpotassemia that were accompanied by normal plasma aldosterone and low renin levels and were responsive to chlorothiazide administration were found in a 29-yr-old patient and, 2 decades later, in his 21-yr-old son. Their renal function is normal, including response to NaSO4, mannitol and aldosterone infusions. Adrenal insufficiency was excluded. The renin-aldosterone system was proved intact by physiological and pharmacologic stress and angiotensin-II infusion. Also normal were values for blood counts, blood volumes, and erythrocyte and exchangeable body K+. The postulation of a defective cell membrane impeding K+ influx is supported by the failure of glucose and insulin infusions to substantially reduce hyperpotassemia. In the context of a hereditary disorder (the pedigree, compatible with autosomal dominant inheritance, includes 5 affected in 2 generations), hypertension is a 2nd phenotypic character of a single defective pleiotropic gene although its pathogenesis remains unclear.