New developments in prenatal diagnosis of congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) owing to 21-hydroxylase deficiency is an autosomal recessive disorder caused by mutations in the CYP21A2 gene. Females affected with classical CAH are at risk for genital ambiguity, but can be treated in utero with dexamethasone before 9 gestational weeks to prevent virilization. Early genetic diagnosis is unavailable through current invasive methods of chorionic villus sampling and amniocentesis.

A rare CYP21A2 mutation in a congenital adrenal hyperplasia kindred displaying genotype-phenotype nonconcordance.

Congenital adrenal hyperplasia (CAH) owing to 21-hydroxylase deficiency is caused by the autosomal recessive inheritance of mutations in the gene CYP21A2. CYP21A2 mutations lead to variable impairment of the 21-hydroxylase enzyme, which, in turn, is associated with three clinical phenotypes, namely, salt wasting, simple virilizing, and nonclassical CAH. However, it is known that a given mutation can associate with different clinical phenotypes, resulting in a high rate of genotype-phenotype nonconcordance.

Pitfalls in hormonal diagnosis of 17-beta hydroxysteroid dehydrogenase III deficiency.

Steroid 17β-hydroxysteroid dehydrogenase III (17β-HSD3) deficiency is a rare autosomal recessive disorder that usually presents in patients with a 46,XY karyotype with ambiguous genitalia at birth. The 17β-HSD3 enzyme, which is encoded by the HSD17B3 gene, converts gonadal delta-4 androstenedione (Δ4) to testosterone (T). Such 17β-HSD3 enzyme deficiency is expected to lead to an increased ratio of D4 to T when the patient undergoes a human chorionic gonadotropin stimulation (hCG) test.