Familial salivary gland insensitivity to aldosterone: a variant of pseudohypoaldosteronism

Two male siblings presented in infancy with hyponatraemia. Levels of plasma renin activity and aldosterone were elevated. Sodium supplementation was necessary to maintain normal sodium balance. Urinary sodium concentration and renal epithelial exchange between sodium and potassium were normal; however, salivary sodium concentrations were markedly elevated with sweat sodium levels being in the upper normal range. Excess salivary sodium loss accounted for sodium depletion in these cases who present a new variant of pseudohypoaldosteronism associated with normal renal sodium transport.