RESUMEN
To undertake mutational analysis in patients with different forms of steroid 21-hydroxylase deficiency. Subjects and CYP21 gene molecular analysis was performed in 76 Czech patients diagnosed with steroid 21-hydroxylase deficiency. Eight of the most common point mutations [intron 2 splice, P30L, 8bp deletion in exon 3, I172N, V281L, Q318X, R356W, and P453S] were analyzed using an amplification-created restriction site method, and 5 additional mutations [intron 7 splice, F307insT, cluster in exon 6, R484P, and R484X] were analyzed using dot-blot hybridization with 5'-biotin-labeled oligonucleotides. Deletions and conversions were screened using a sequence-specific oligonucleotide hybridization method. Comparison of common mutation frequencies in CYP21 reported for different regions, both within Europe and worldwide [North and South America, Asia, and North Africa], was undertaken and the significance of the differences was determined by statistical analysis [Fisher's F test, Student's t test, paired t test, and confidence intervals] using a value of p < 0.05. The most frequent genetic defect found in this group of Czech patients was intron 2 splice mutation [46.7%]. Comparison of mutation frequencies between Czech and other European populations showed that the Czech patients had a lower frequency of deletions/large gene conversions, R356W, and cluster mutations in exon 6, together with a higher frequency of intron 2 splice mutation, 8-bp deletion and F307insT compared with other populations. A high prevalence of P30L mutations, mostly associated with nonclassical forms of congenital adrenal hyperplasia, was found in Czech patients with classic simple virilizing forms of steroid 21-hydroxylase deficiency