Identification of heterozygotic carriers of 21-hydroxylase deficiency: sensitivity of ACTH stimulation tests.
Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is a common autosomal-recessive disorder. To ascertain carrier status, adrenocorticotropin (ACTH) stimulation tests are often used. To determine the sensitivity of ACTH stimulation to detect heterozygotes and to correlate stimulated 17-hydroxyprogesterone responses with molecular genotype, we compared molecular genetic analysis of the 21-hydroxylase (CYP21) gene with 17-hydroxyprogesterone responses at 30 min in 51 individuals. Molecular genotype analysis and ACTH stimulation tests were performed in healthy volunteers (n = 20) and relatives of patients with congenital adrenal hyperplasia (n = 31). Polymerase chain reaction (PCR) amplification, single-strand conformational polymorphism (SSCP) analysis, allele-specific oligonucleotide hybridization (ASOH) analysis, and restriction fragment length polymorphism (RFLP) analysis were utilized to screen for 14 CYP21 mutations which account for >90% of the mutations associated with 21-hydroxylase deficiency. Molecular genotype analysis classified 28 individuals as heterozygotic carriers and 23 individuals as normal for all mutations tested. As a group, the heterozygotes had significantly greater stimulated 17-hydroxyprogesterone responses at 10 and 30 min (P < 0.0005). However, on an individual basis, 14/28 (50%) genotyped heterozygotic carriers had stimulated 17-hydroxyprogesterone concentrations, 17-hydroxyprogesterone/cortisol ratios, and 17-hydroxyprogesterone incremental elevations indistinguishable from the genotyped normal individuals. Thus, a normal 17-hydroxyprogesterone response to ACTH stimulation testing does not exclude carrier status for 21-hydroxylase deficiency. Molecular genotype analysis is a more reliable method to determine 21-hydroxylase heterozygotes.
Witchel
S F
SF
Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh, Pennsylvania 15213, USA. sfs@med.pitt.edu
Lee
P A
PA
D019326:17-alpha-Hydroxyprogesterone / Q000378:metabolism; D000312:Adrenal Hyperplasia, Congenital / Q000235:genetics*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D005260:Female; D006580:Genetic Carrier Screening; D005838:Genotype; D006801:Humans; D008297:Male; D009154:Mutation; D009841:Oligonucleotides; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D018807:Polymorphism, Single-Stranded Conformational; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013255:Steroid 21-Hydroxylase / Q000235:genetics
D009841:Oligonucleotides; D019326:17-alpha-Hydroxyprogesterone; D000324:Adrenocorticotropic Hormone; D013255:Steroid 21-Hydroxylase