Phenotypical, biological, and molecular heterogeneity of 5α-reductase deficiency: an extensive international experience of 55 patients.

Context: In 46,XY disorders of sex development, 5α-reductase deficiency is rare and is not usually the first-intention diagnosis in newborn ambiguous genitalia, contrary to partial androgen insensitivity syndrome. Yet the cause of ambiguous genitalia may guide sex assignment, and rapid, precise diagnosis of 5α-reductase deficiency is essential.

Objective: The aim of the study was to describe relevant data for clinical diagnosis, biological investigation, and molecular determination from 55 patients with srd5A2 mutations identified in our laboratory over 20 yr to improve early diagnosis.