Clinical characterization and analysis of the SRD5A2 gene in six Korean patients with 5alpha-reductase type 2 deficiency.

AIMS: The aim of this study was to perform a 5alpha-reductase type 2 gene (SRD5A2) analysis in 6 Korean patients with external genitalia ranging from predominantly female to male in whom 5alpha-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 5alpha-reductase type 2 deficiency. Identification of mutations also enables genetic counseling for families at risk.