Congenital adrenal hyperplasia causes by 21-hydroxylase deficiency (CAH - 21OH) is an autosomal recessive genetic disorder due to mutation in the CYP21A2 gene. The aim of this study was to identify mutations of CYP21A2 gene in patients with CAH - 210H and detect the carrier in family members of CAH - 21OH patients. 33 CAH - 21OH patients and 78 family members were selected for this study
direct DNA sequencing and MLPA were used to identify the mutation and carriers in CYP21A2. The result showed that, in the patient group, 33/33 (100 percent) patients were found to have mutation in CYP21A2 gene with 7 different types of mutation and 656 AlC G (IVS2 - 13A1C G) was the most common mutation with 13/33 (39.5 percent) and following is the deletion mutation with 7/33 (21.2 percent). In the carrier group, 32/33 fathers, 33/33 mother and 5/12 siblings were identified as carrier. The results are important for prenatal diagnosis and genetic counseling to reduce the ratio of disease and have suitable treatment for mother in initial weeks of gestation.