Endocrine Abstracts

5-Alpha reductase deficiency is a rare 46, XY disorder of sex differentation caused by mutations in the 5-alpha reductase type 2 gene (SRD5A2) located on chromosome 2p23. Affected patients have a deficiency of the 5-alpha reductase type 2 enzyme, which becomes partially or totally unable to convert testosterone into dihydrotestosterone, the latter being responsible for the development of the external genitalia, prostate, and urethra in the male fetus. Most affected individuals are characterized at birth by predominantly female external genitalia and are often raised as girls. Patients raised as girls exhibit spontaneous virilization at puberty. Some patients are sufficiently masculinized at birth and are raised as boys.

In this article we describe a 22-year-old patient who had female external genitalia at birth and was raised as a girl. When puberty was reached, she had amenorrhea, virilization and lack of secondary sex characteristics. For these reasons, she was brought to our clinic and 5-alpha reductase deficiency was diagnosed. The woman exhibited a masculine build and muscle development, male hair characteristics, micropenis, and perineoscrotal hypospadias. Testes were palpable in the right and left inguinal canals. Chromosome analysis revealed a 46,XY karyotype. On pelvic MRI, ovaries and uterus were absent. A 41×11 mm vagina-like structure was seen, as were testes within labia-like scrota bilaterally, and seminal vesicles with corpus cavernosa. Hormonal studies included serum total testosterone level 1.54–2.67 ng/mL (normal: 0.1–0.75), free testosterone level 13.79 pg/ml (normal: 0.29–3.18), free androgen index 40%, 17-OHP level 2.34 ng/ml (normal: 0.5–2.4), FSH 28.23 IU/ml (normal: 1.7–19.26), and LH 7.93 mIU/ml (normal: 1.24–8.22). While the serum testosterone was 9.80 nmol/l, serum DHT was 0.52 nmol/l and T/DHT ratio was calculated to be 18.8 (normal is <12). Upon further analysis of the 5-alpha reductase type 2 gene, a previously unreported heterozygous R178S mutation was found.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.