Evidence for endocrinological abnormalities in heterozygotes for adrenal 11 beta-hydroxylase deficiency of a family with the R448H mutation in the CYP11B1 gene.

In about 5% of cases of classical congenital adrenal hyperplasia, steroid 11 beta-hydroxylase deficiency is the underlying defect. In two publications, no biochemical abnormalities have been reported in obligate heterozygotes for 11 beta-hydroxylase deficiency. We found the typical plasma steroid pattern of 11 beta-hydroxylase deficiency and identified the R448H mutation in the CYP11B1 gene in a boy presenting with pseudoprecocious puberty at age 2 yr. Both parents and an older sister were genotyped and were heterozygous carriers for the R448H mutation in CYP11B1. In contrast to the data reported in the literature, we found increased responses of plasma 11-deoxycortisol and 11-deoxycorticosterone in the short term ACTH test in the three family members heterozygous for the R448H mutation.