Neonatal salt-wasting syndromes are rare but potentially serious conditions. Isolated hypoaldosteronism is an autosomal recessive inherited disorder of terminal aldosterone synthesis, leading to selective aldosterone deficiency. Two different biochemical forms of this disease have been described, called aldosterone synthase deficiency or corticosterone methyl oxydase, types I and II. In type I, there is no aldosterone synthase activity and the 18 hydroxycorticosterone (18 OHB) level is low, whereas in type II, a residual activity of aldosterone synthase persists and 18 OHB is overproduced. We report on four patients with isolated hypoaldosteronism. In 2 of them, who were recently diagnosed with aldosterone synthase deficit, we discuss the symptoms and treatment. The 2 other patients are now adults. We discuss the long-term outcome, the quality of adult life, aldosterone synthase deficits, as well as the pathophysiology and molecular analysis., (Copyright © 2012. Published by Elsevier SAS.)