Background: Congenital adrenal hyperplasia owing to 17 alpha-hydroxylase/17, 20-Iyase deficiency is caused by genetic mutations in the CYP17A1 gene. To date, more than 80 different genetic lesions have been described in patients suffering from this disorder. We aimed to estimate the prevalence of CYP17A1 common mutations in Chinese Han population. Methods: We first reported two female patients with 17 alpha-hydroxylase deficiency based on their clinical features and molecular genetics, and then summarized all the mutations of CYP17A1 gene reported around the world. The most common mutations of CYP17A1 among Chinese Han were genotyped in additional 3245 healthy Chinese using Taqman-assays. Results: The mutation spectrum in Asian is different from European decent. All healthy controls could detect two CYP17A1 mutations, D487-S488-F489 deletion and TAC329AA, with a prevalence of 1 in 1000 or 2 in 1000, respectively. Conclusion: Our data demonstrates that these two mutations are major causes of 17a-hydroxylase deficiency in Chinese Han population. (C) 2011 Elsevier B.V. All rights reserved.