Identification of frequency of the 9 most frequently CYP21 gene mutations in Turkish patients with 21-OHD

SUMMARYIdentification of Frequency and Distribution of the 9 Most Frequently Mutations in TurkishPatients with 21-OHD.Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders mainly due todefects in the steroid 21- hydroxylase (CYP21) gene. To determine the mutational spectrum in theTurkish population, the CYP21 active gene was analyzed in 100 unrelated patients using PCR andRFLP. All patients had a classical form of 21-hydroxylase deficiency. Mutations were detected in 78patients (allele frequencies; %77.5). The most frequent mutation in the Turkish CAH population wasfound to be IVS2, with %28.5 allele frequency.The allele frequencies of the other mutations were asfollows: 8bp; %4, BD; %17, P30L; %1.5, I172N; %4, E6 Cluster; %1, V281L; %4.5, Q318X; %12.5,R356W; %4.5.Key Words: Congenital adrenal hyperplasia, CYP21 gene, Mutation, Turkish, 21-OHD.