CYP17A1 mutations identified in 17 Chinese patients with 17α-hydroxylase/17,20-lyase deficiency

Context: 17α-hydroxylase deficiency (17OHD) is a relatively rare disease, accounting for about 1% of congenital adrenal hyperplasia cases. The CYP17A1 gene mutation can lead to this disease. Human CYP17A1 gene is located on chromosome 10q24.3. It consists of eight exons encoding 508 amino acids. To date, more than 50 mutations in exons and introns of the CYP17A1 gene have been reported to cause complete or partial 17OHD. Objective: The aim of this study was to investigate the CYP17A1 gene mutation types in 17 Chinese patients, containing 11 complete and six partial 17OHD patients. Setting: We conducted the study in the Department of Obstetrics and Gynecology of Peking Union Medical College Hospital. Patients: Seventeen patients were studied with complete or partial 17OHD. Main outcome measures: The CYP17A1 gene was sequenced and we measured steroid and sex hormone levels. Results: Analysis of the CYP17A1 gene in our patients revealed 12 different kinds of mutation. Two mutations (IVS1-1G>A and L209P) were novel mutations. Mutation c.985_987delTACinsAA (Y329KfsX418) in Exon 6 was the most common mutation in Chinese patients, accounting for 50 percents of the mutant alleles (17/34). Exon 6 was the hot spot since most mutations were detected in this exon (59%, 20/34 alleles). There was no mutation detected in the Exons 4 and 5.