Mutational analysis and genotype-phenotype correlation in patients with classic 21-hydroxylase deficiency from transylvania (north-west Romania).

The regional incidence of 21-hydroxylase deficiency, its mutational spectrum and the correlation of genotype and phenotype has been studied by European, American and Latin-American groups. However, little information is known about the molecular background of the disease in patients from Central-Eastern Europe. The present study aimed to genotype a group of patients from Transylvania, the north-western part of Romania, in order to gain some insight into the molecular pattern and the genotype-phenotype correlation of congenital adrenal hyperplasia (CAH) in this region. We genotyped 17 patients with classic 21-hydroxylase deficiency and, whenever available, their parents in order to verify mutational segregation. The patients came from 13 unrelated families. DNA was prepared from peripheral blood leucocytes and four gene fragments were amplified by PCR. The 21-hydroxylase gene (CYP21B) was completely sequenced and analyzed for point mutations or deletions. Percentage distribution of mutations was as follows: 12G--34.6%, deletions and large conversions (del)--19.2%, P30L--15.4%, 1172N--15.4%, P30L+I2G+del8bp (triple mutation)--11.5%, and R356W--3.8%. Mutational percentage distribution compared to other Latin populations is higher for I2G and I172N and lower for deletions, while the P30L mutation was found at a higher rate than in any other analyzed population. Some differences may arise from the low patient number and from ethnic particularities. The incidence of compound heterozygotes in our group was 76.5%. The genotype seemed to correlate fairly well to phenotype, with a general concordance rate of 82.35%. Clear divergence was found in two patients with the simple virilizing form, exhibiting a homozygous status for I2G and del, respectively. This study offers the first information about the molecular pathology of CAH in Romania and should help to improve management and clinical outcome for patients with CAH in Transylvania. Hopefully, it might also be the first step towards exact and accurate prenatal diagnosis in our country.