Steroid 17alpha-hydroxylase deficiency: functional characterization of four mutations (A174E, V178D, R440C, L465P) in the CYP17A1 gene.

Context: Steroid 17alpha-hydroxylase (CYP17A1, alias P450c17) deficiency (17OHD) is a rare form of congenital adrenal hyperplasia. The CYP17A1 enzyme catalyzes two distinct reactions, 17alpha-hydroxylase and 17,20-lyase activities.

Objective: The aim of the study was to analyze the structural and functional consequences of three novel (A174E, V178D, and L465P) and one previously reported (R440C) CYP17A1 mutation found in three patients clinically and biochemically presenting with 17OHD.

Functional characterization of three CYP21A2 sequence variants (p.A265V, p.W302S, p.D322G) employing a yeast co-expression system.

Congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase (CYP21A2) deficiency is the commonest inborn error in steroid hormone biosynthesis. Functional in vitro assessment of mutant activity generally correlates well with clinical phenotype and therefore has contributed greatly to phenotype prediction in this CAH variant. Three CYP21A2 sequence variants (g.