Pseudohypoaldosteronism: mutation found, problem solved?

The term 'pseudohypoaldosteronism' includes at least three distinct clinical syndromes, classified as type I, II and III, which differ in their clinical and biochemical findings but have in common the symptoms of mineralocorticoid resistance. The finding of a defect in the recently cloned epithelial sodium channel (ENaC) in a subgroup of familial pseudohypoaldosteronism type I has changed our understanding not only of the pathophysiology of these disorders but also the physiology of renal salt and water homeostasis. In this review the various clinical, biochemical and genetic findings in the different forms of pseudohypoaldosteronism will be discussed with the aim of identifying the underlying differences and similarities. The direction of further genetic investigations will depend at least in large part on further clinical classification of patients and families.