A partial form of pseudohypoaldosteronism type I without renal sodium wasting.

Multiple target organ involvement in pseudohypoaldosteronism is known but partial defects involving only a single organ system have also been described. In this report we present a girl with early symptoms and a very mild course of the disease without renal salt wasting and with normal sweat osmolality. Sodium content and the sodium/potassium ratio of stool was highly elevated. Increased plasma renin activity and aldosterone concentration as well as a reduced number of aldosterone receptors in mononuclear leucocytes confirmed the diagnosis of pseudohypoaldosteronism. Partial pseudohypoaldosteronism maybe more frequent than currently diagnosed since salt loss can be compensated by intact organ systems, but nevertheless threatens the young patient during illness. Since various degrees of clinical severity of pseudohypoaldosteronism even in the same family have been described, it seems important to identify mild cases in order to monitor younger siblings.