IDENTIFICATION OF HETEROZYGOTIC CARRIERS OF 21-HYDROXYLASE DEFICIENCY- SENSITIVITY OF ACTH STIMULATION TESTS

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is a c ommon autosomal-recessive disorder, To ascertain carrier status, adren ocorticotropin (ACTH) stimulation tests are often used, To determine t he sensitivity of ACTH stimulation to detect heterozygotes and to corr elate stimulated 17-hydroxyprogesterone responses with molecular genot ype, we compared molecular genetic analysis of the 21-hydroxylase (CYP 21) gene with 17-hydroxyprogesterone responses at 30 min in 51 individ uals, Molecular genotype analysis and ACTH stimulation tests were perf ormed in healthy volunteers (n = 20) and relatives of patients with co ngenital adrenal hyperplasia (n = 31), Polymerase chain reaction (PCR) amplification, single-strand conformational polymorphism (SSCP) analy sis, allele-specific oligonucleotide hybridization (ASOH) analysis, an d restriction fragment length polymorphism (RFLP) analysis were utiliz ed to screen for 14 CYP21 mutations which account for > 90% of the mut ations associated with 21-hydroxylase deficiency, Molecular genotype a nalysis classified 28 individuals as heterozygotic carriers and 23 ind ividuals as normal for all mutations tested, As a group, the heterozyg otes had significantly greater stimulated 17-hydroxyprogesterone respo nses at 10 and 30 min (P < 0.0005), However, on an individual basis, 1 4/28 (50%) genotyped heterozygotic carriers had stimulated 17-hydroxyp rogesterone concentrations, 17-hydroxyprogesterone/cortisol ratios, an d 17-hydroxyprogesterone incremental elevations indistinguishable from the genotyped normal individuals, Thus, a normal 17-hydroxyprogestero ne response to ACTH stimulation testing does not exclude carrier statu s for 21-hydroxylase deficiency, Molecular genotype analysis is a more reliable method to determine 21-hydroxylase heterozygotes. (C) 1998 W iley-Liss, Inc.