Combined 21-hydroxylase and 11 beta-hydroxylase deficiency: Patient reportand molecular basis

A female newborn (46, XX) with ambiguous genitalia was initially diagnosed by biochemical criteria as having classical congenital adrenal hyperplasia caused by 11 beta-hydroxylase deficiency, Shortly after effective; treatmen t was administered, she developed a salt-wasting crisis with severe electro lyte imbalance. DNA analysis revealed a homozygous splice mutation in the s econd intron of the CYP21 gene, for which both parents were heterozygous, N o mutations were found in the entire CYP11B1 gene, thus proving that the 11 beta-hydroxylase deficiency was not caused by a gene mutation but rather w as a secondary event, possibly due to androgen suppression of 11 beta-hydro xylase activity.