Clinical Characterization and Analysis of the SRD5A2 Gene in Six Korean Patients with 5α-Reductase Type 2 Deficiency

Aims: The aim of this study was to perform a 5α-reductase type 2 gene (SRD5A2) analysis in 6 Korean patients with external genitalia ranging from predominantly female to male in whom 5α-reductase type 2 deficiency was suspected. Patients: Six patients from five unrelated families participated, and all of their parents were non-consanguineous. Three patients presented with ambiguous genitalia at birth, and 2 were referred owing to delayed puberty. The other patient was presented incidentally during an operation for inguinal hernia. Basal and post-human chorionic gonadotropin-stimulated serum testosterone and dihydrotestosterone levels were determined, but neither the levels nor ratio yielded enough information for differential diagnosis. Confirmative diagnosis was achieved by SRD5A2 gene analysis. Results: Four different pathologic mutations were identified. All have already been reported, and are located in exon 1 (p.Q6X), exon 4 (p.G203S and c.655delT), and exon 5 (p.R246Q). p.R246Q was the most frequently identified mutation in our study, and c.655delT has been detected only in Korean patients to date. Conclusion: The molecular analysis is the most reliable method for a correct diagnosis of 5α-reductase type 2 deficiency. Identification of mutations also enables genetic counseling for families at risk.