SCREENING OF CYP21 GENE-MUTATIONS IN 129 FRENCH PATIENTS AFFECTED BY STEROID 21-HYDROXYLASE DEFICIENCY

The frequency of 12 different mutations of the steroid 21-hydroxylase gene (CYP21) was investigated in 129 French patients affected by conge nital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficien cy. Eighty nine percent of the CAH chromosomes were characterized, The most frequent mutations were a C-G substitution in intron 2, the dele tion of the CYP21 gene and a TA substitution in exon 4 in the severe f orm of the disease, and a G-T substitution in exon 7 in the nonclassic form. The correlation between the genotypes and the clinical forms of the disease showed marked variation in the phenotype from a single ge notype, suggesting that individual variation and undetected additional mutations on the same CAH chromosome accounted for the phenotype. In 65 informative meioses of CAH families, no de novo mutation was found. (C) 1995 Wiley-Liss, Inc.