Endocrine Abstracts

Introduction: The testicular disorder of sexual differentiation (DSD) is a rare clinical condition with a reported incidence of 1:20 000 newborn males. It is characterised by a male phenotype with 46,XX karyotype. There are three clinical phenotypes: normal male phenotype, males with genital ambiguities and males who are true hermaphrodites. SRY positive 46,XX testicular DSD results from the translocation of a Y chromosome segment containing the SRY gene during spermatogenesis. In rare cases, the SRY gene may be misplaced onto a chromosome other than the X chromosome.

Case report: A 33 years old male presented with his wife to the fertility clinic with a 3 years history of primary infertility. The patient’s wife had no significant past medical history, her clinical examination was unremarkable and her biochemical and hormonal investigations were all normal. The patient had a past medical history of appendicectomy, lumbar discopathy and undescended testes in childhood. There was no significant family history. He had normal libido and sexual function. Clinical examination revealed a normal height and bilateral small testes. His total testosterone was 6.7 nmol/l, LH was 4.4 IU/l and FSH was 43.1 IU/l. A sample was sent for sperm analysis which revealed azoospermia. His viral screen was negative. Genetic analysis for cystic fibrosis was negative. The patient was sent for chromosomal analysis and karyotyping using fluorescence in situ hybridization (FISH) technique. This revealed a 46XX SRY positive karyotype through translocation of the SRY gene between the X and the Y chromosome – 46,XX der(X)t(X;Y)(p22.3;p11.3)(SRY+).

Conclusion: Patients with azoospermia should be karyotyped. Sperm donation remains a fertility treatment option for patients with DSD and had a successful outcome in this patient. Such patients require lifelong follow-up led by an endocrinologist with regular imaging of their gonads, bone density measurements, and testosterone supplementation.