Prenatal diagnosis and treatment of 11β-hydroxylase deficiency congenital adrenal hyperplasia resulting in normal female genitalia

Congenital adrenal hyperplasia (CAH) consists of autosomal recessive disorders of cortisol biosynthesis, which in the majority of cases result from 21-hydroxylase deficiency. Another enzymatic defect causing CAH is 11β-hydroxylase deficiency. In both forms, the resulting excessive androgen secretion causes genital virilization of the female fetus. For over 10 yr female fetuses affected with 21-hydroxylase deficiency have been safely and successfully prenatally treated with dexamethasone. We report here the first successful prenatal treatment with dexamethasone of an affected female with 11β-hydroxylase deficiency CAH. The family had two girls affected with 11β-hydroxylase deficiency born with severe ambiguous genitalia who were both homozygous for the T318M mutation in the CYP11B1 gene, which codes for the 11β-hydroxylase enzyme. In the third pregnancy in this family, the female fetus was treated in utero by administering dexamethasone to the mother, starting at 5 weeks gestation. The treatment was successful, as the newborn was not virilized and had normal female external genitalia. A second family with two affected sons was also studied in preparation for a future pregnancy. We report a novel 1-bp deletion in codon 394 (R394Δ1) in the CYP11B1 gene in this family.