Preliminary investigation of mutations in 21‐hydroxylase gene in patients with congenital adrenal hyperplasia in Russia

Mutations in 21 hydroxylase gene were investigated in 40 Russian patients with congenital adrenal hyperplasia. Quantitative amplification/restriction procedure was used for detection of mutations involving promoter region, 3 and 8 exons. For affected chromosomes alleles of tightly linked HLA A and B genes were defined, as well as 5 different alleles or allele combinations of HLA DQA1 gene. The most frequent (>20% of chromosomes) cause of salt wasting adrenal hyperplasia in Russia is a chimeric CYP21A‐CYP21B gene with normal copy of a pseudogene which results from gene conversion in chromosome with B14‐DQA1 0101/0102 haplotype. The second common mutation (about 10%) is a result of intragenic recombination well‐known deletion of the gene linked with A3‐B47‐DQA1 0201/0601 haplotype. Two other mutations were linked with A3‐B35‐DQA1 0401/0402 and A3‐B40‐DQA1 0201/0601 haplotypes. © Wiley‐Liss, Inc.