A prevalent and three novel mutations in CYP11B1 gene identified in Chinese patients with 11-beta hydroxylase deficiency

Abstract

11β-Hydroxylase deficiency (11β-OHD), caused by CYP11B1 mutations, is characterized by hyporeninemic, hypokalemic hypertension and hyperandrogenism. We identified a prevalent and three novel mutations of CYP11B1 gene in nine patients with classic 11β-OHD. Subjects and methodsNine patients with 11β-OHD from unrelated families were recruited. The complications of 11β-OHD occurred in three patients who never received glucocorticoid treatment. CYP11B1 gene was sequenced and 11β-hydroxylase enzymatic activities were assessed in vitro. A haplotype analysis was performed to determine a common ancestor for those subjects who carried the same p.R454C mutation. ResultsCYP11B1 gene mutations were identified in all patients, with a prevalent (p.R454C) and three novel mutations (p.V148G, IVS7-9C>A, c.1359_1360insG). The p.R141X, p.V148G, c.1359_1360insG and p.R454C mutations retained 4.9%, 3.9%, 3.7%, 4.5% of residual enzymatic activity, respectively. Five of nine patients carried p.R454C mutation, which was only reported in Chinese 11OHD patients. Haplotype analysis showed that this mutation might be inherited from a common ancestor. ConclusionThe enzymatic activities for p.R141X, p.V148G, c.1359_1360insG and p.R454C mutants were almost completely abolished, which corresponds to classic form of 11β-OHD. The observations of a prevalent mutation and three novel mutations might have potential clinical utility for genetic counseling and prenatal diagnosis in Chinese 11β-OHD patients.