Classical 11β-Hydroxylase Deficiency Caused by a Novel Homozygous Mutation: A Case Study and Literature Review

Congenital adrenal hyperplasia (CAH) is an uncommon condition and 11β-hydroxylase deficiency (11βOHD) accounts for 0.2-8% of cases. In this study, we report a three-year-old girl with a known diagnosis of classical CAH on maintenance treatment with hydrocortisone who presented with abnormal genitalia and persistent hypertension. Genetic testing confirmed the diagnosis of autosomal recessive CAH due to 11βOHD as a result of a novel homozygous pathogenic mutation, c.53dup p.(Gln19Alafs*21), in the CYP11B1 gene. Physicians should consider the possibility of classical 11βOHD in CAH patients presenting with persistent hypertension, even if other laboratory biomarkers are equivocal.