A Rare Case of Apparent Mineralocorticoid Excess Presenting as Endocrine Hypertension

Abstract

A 3-year-old boy presented with polyuria and polydipsia for 18 months, along with growth failure. He was born prematurely, at 34 weeks of gestation, with a low birth weight. On examination, the child was severely underweight and hypertensive. Clinical history and evaluation could not identify any secondary causes of hypertension. There was no significant family history. An endocrine workup was planned, considering hypokalemia and metabolic alkalosis. This demonstrated hyporeninemic hypoaldosteronism and raised the possibility of apparent mineralocorticoid excess (AME) and Liddle syndrome. Clinical exome sequence analysis of HSD11B2 revealed a homozygous mutation in exon 5 (911A>G; p.His304Arg), which resulted in a missense mutation that confirmed the diagnosis of AME. A novel homozygous variant was found in the HSD11B2 gene in a subject with early onset hypertension associated with hypokalemic metabolic alkalosis, establishing the diagnosis of AME.