Variable expression of 5α-reductase deficiency: Presentation with male phenotype in a child of greek origin

A male infant with perineal hypospadias and a small phallus bound in chordee is described. Biochemical investigation at age 9 months after hCG stimulation revealed a testosterone to dihydrotestosterone (DHT) ratio of 40, a markedly elevated value suggestive of deficient steroid 5α-reductase activity. The diagnosis of 5α-reductase deficiency was confirmed by elevated urinary 5β/5α-steroid metabolite ratios and demonstration of defective 5α-reductase activity in cultured fibroblasts from the patient's scrotum and foreskin. Application of DHT cream to the patient's abdomen raised circulating levels of DHT to the adult male range. Two courses of DHT given nightly for 3 and 4 months resulted in phallic enlargement. Surgical release of the chordee and hypospadias repair have resulted in normal male appearance of the genitalia. This case illustrates the heterogeneity of the 5α-reductase deficiency phenotype.