21-Hydroxylase activity was measured in North American Caucasian individuals with the HLA-B14 antigen to estimate the frequency of heterozygosity for the attenuated congenital adrenal hyperplasia trait. A 30-min iv ACTH stimulation test was administered to 9 normal HLA-Bl4-positive subjects and to a comparable HLA-Bl4-negative control group. Changes in plasma progesterone and 17-hydroxyprogesterone over 30 min were summed and expressed as a combined rate of rise. Six of 9 HLA-Bl4-positive individuals had a rate of rise greater than 2 SD above the mean control value. On this basis, about two thirds of B-14-positive individuals are heterozygote carriers for 21-hydroxylase deficiency. Thus, the frequency of the attenuated form of congenital adrenal hyperplasia linked to the HLA-B14 locus in women is approximately 1 in 6000 if there is only 1 B14, and 1 in 2000 if there are 2 Bl4s in the HLA type.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical