Purpose: To investigate CYP 7A1 gene mutations in Chinese patients with 17alpha-hydroxylase deficiency.
Methods: Clinical data were retrospectively analyzed. CYP17A1 mutations were detected in two cases with 17alpha-hydroxylase deficiency. Genomic DNA was isolated from blood samples and eight primers pairs were used to amplify eight exons and exon-intron boundaries of the CYP17A1 gene. The amplified PCR products were purified by agarose gel electrophoresis and then directly sequenced. Sequencing results were compared to the established human CYP17A1 sequence.
Results: Two compound mutations were identified: TAC --> AA at codons 436-438 on exon 6, causing the amino acid missense mutation Y329K/418X; and deletion of the 9-bp sequence GACTCTTTC at codons 487-489 on exon 8, causing deletion of three amino acids (Asp-Ser-Phe).
Conclusion: D487_F489del and Y329K, 418X CYP17A1 mutations were identified in our two patients. A literature review revealed that the main CYP17A1 mutations in the Chinese population are missense and splicing defects, and exons 8 and 6 are most frequently involved.