[Analysis of the spectra of mutational damage of the 21-hydroxylase gene in patients with adreno-genital syndrome].

The spectrum of mutations in the steroid 21-hydroxylase gene (CYP21B) and the frequency of 11 mutations among 66 patients with different forms of congenital adrenal hyperplasia (CAH) were analyzed by means of PCR amplification. Each of the CAH forms was characterized by specific spectrum of diagnostically important mutations. The salt-losing (SL) form of the disease was most frequently associated with gene deletion (39%) and the 668-13C-G mutation in the second intron (23.5%), whereas the majority of simple virilizing (SV) CAH cases were associated with the 1172N mutation in exon 4 (22%), gene deletion (16.5%), and the 668-13C-G mutation (16.5%). Mutations in the steroid 21-hydroxylase gene were detected in 70% of the chromosomes from the patients with the SL and SV forms of CAH, and only in 1.3% of the chromosomes from the patients with the nonclassic (NC) form. A total of 78 mutant chromosomes from the NC CAH patients were examined, and only one case of a gene deletion in the heterozygous state was revealed. In the individuals examined, the V281L and P30L mutations described in the NC CAH patients from other populations were not detected. This result can be explained either by the fact that NC CAH cases in Russia are associated with other major mutations, or by difficult clinical diagnosis questionable CAH cases.