Isolated Aldosterone Deficiency Due to an Aldosterone Synthase Mutation: A Rare Cause of Life-Threatening Salt Wasting in Infancy

Abstract

Purpose: Isolated hypoaldosteronism is a rare cause of salt wasting in infancy caused by the loss of activity of aldosterone synthase (AS), which is encoded by the CYP11B2 gene. This condition may be life-threatening, especially in newborns. Methods: We are reporting the case of a newborn male born to consanguineous parents, who presented at the age of 1 month with severe dehydration, vomiting, and hypotonia. Results: Lab studies showed severe hyponatremia, hyperkalemia, and metabolic acidosis. Hormonal assessment confirmed a normal corticotrope axis with severe deficiency in aldosterone. Genetic analysis revealed a novel mutation in the CYP11B2 gene in the highly conserved donor splice site of exon 3 and confirmed the isolated aldosterone deficiency. The patient was subsequently treated with fludrocortisone and sodium only, without hydrocortisone. Conclusion: AS deficiency is a rare inherited disease. There should be a high index of suspicion of cases with life-threatening salt-wasting in infancy as dramatic clinical improvements and good long-term prognosis can be achieved with timely replacement treatment.