Complexities of gender assignment in 17β-hydroxysteroid dehydrogenase type 3 deficiency: is there a role for early orchiectomy?

Background: 17β-Hydroxysteroid dehydrogenase type-3 (17βHSD-3) deficiency is a rare cause of 46,XY disorders of sex development. The enzyme converts androstenedione to testosterone, necessary for masculinization of male genitalia in utero. 17βHSD-3 deficiency is frequently diagnosed late, at puberty, following virilization, with consequent female-to-male gender reassignment in 39-64%. The decision for sex of rearing is difficult, especially if diagnosed in early childhood. Consensus guidelines are equivocal or support male gender assignment. Long-term outcomes data to guide decisions are also lacking; however, in the few cases of early diagnosis and orchiectomy, female gender retention appears more likely.We report two patients with 17βHSD-3 deficiency, who presented at unusual ages, in whom female gender was chosen. We performed a focused literature review and summary of gender outcomes in 17βHSD-3 deficiency following early orchiectomy.

Cases: Patient A was a phenotypic female who presented at one year of age with bilateral inguinal hernias and external female genitalia. Testes were identified at surgery. The karyotype was 46,XY. She was initially diagnosed with complete androgen insensitivity syndrome; however, androgen receptor mutation analysis was negative. Human chorionic gonadotropin stimulation yielded a low testosterone: androstenedione ratio (0.6, normal >0.8). Genetic testing demonstrated compound heterozygosity for two known mutations of the HSD17B3 gene. She underwent bilateral orchiectomy at two years of age.Patient B was born with female genitalia and virilized at 13 years of age. She did not seek evaluation until 22 years of age. Her karyotype was 46,XY. She had bilateral inguinal testes and low testosterone: androstenedione ratio (0.3). HSD17B3 gene sequencing showed her to be a compound heterozygote for two known mutations. She identified herself as female and underwent bilateral orchiectomy and estrogen replacement therapy.

Conclusions: These two patients highlight the complexities of diagnosis and management in 17βHSD-3 deficiency. Although existing data are limited, early orchiectomy is likely to result in retention of female gender identity, avoiding the complications related to virilization in adolescence. As such, it is important to pursue a definitive diagnosis to guide clinical decisions, and to have the support and long term follow up with an inter-disciplinary disorders of sex development team.