Clinical and Genetic Characteristics of 17 α-Hydroxylase/17, 20-Lyase Deficiency: c.985_987delTACinsAA Mutation of CYP17A1 Prevalent in the Chinese Han Population.

OBJECTIVE

17 α-hydroxylase/17, 20-lyase deficiency (17-OHD) is a rare recessive hereditary disease that can be attributed to cytochrome P450 17 α-hydroxylase deficiency caused by CYP17A1 gene mutations.

METHODS

A large cohort of 10 Chinese Han patients with 17-OHD from 2012 to 2020 were enrolled. The clinical and biochemical features were investigated, and genetic mutations of CYP17A1 were analyzed by polymerase chain reaction-Sanger sequencing. Karyotype identification and the SRY gene test were also carried out. In silico analysis was used to predict the effects of genetic mutations on the protein function.

RESULTS

All patients were female. Common complaints were hypertension, hypokalemia, and primary amenorrhea. The karyotype was 46, XY, and the SRY gene was detected in 7 patients; the karyotype was XX in the remaining 3 patients. A total of 7 mutations including Y329N, Y329X, Y329Lfs∗, R96W, A82D, S380N, and A487_P489del have been identified in the CYP17A1 gene. The Y329Lfs∗ mutation was found in 9/10 (90%) of patients with a high allele frequency of 70%. In silico prediction showed that a novel variant of c.1139G>A (S380N) occurs at a conserved residue and can cause disease.

CONCLUSION

We presented a detailed description of the clinical and genetic characteristics in Chinese patients with 17-OHD and concluded that Y329Lfs∗ mutation of CYP17A1 is prevalent in the Chinese Han population. Therefore, hotspot screening by polymerase chain reaction-Sanger sequencing for exon 6 of CYP17A1 could contribute to the rapid diagnosis of 17-OHD in China. Genetic counseling based on the genetic diagnosis for at-risk relatives is advised.