Endocrine Abstracts

Introduction: The clinical differentiation between androgen insensitivity syndrome (AIS) and 5 alpha reductase deficiency (5-ARD) can be difficult. Presenting features may be similar and initial investigations may still not be discriminatory.

Methods: Case notes on a total of ten patients with the initial diagnosis of AIS or 5-ARD were retrospectively reviewed.

Results: All ten children had a 46XY male karyotype. Four children were raised as male. Three out of the six females had an initial diagnosis of AIS, but subsequent re-evaluation revealed a diagnosis of 5-ARD. The age at diagnosis in the 5-ARD group ranged from birth to 12.4 years. A sibling pair who had had previous gonadectomies and negative androgen mutations on genetic analysis was reinvestigated due to the development of clitoromegaly. A urine steroid profile (USP) and then genetic analysis confirmed the diagnosis of 5-ARD. A child whose sibling had complete AIS also subsequently had a diagnosis of 5-ARD on urine steroid profile. Interestingly, one male infant presenting with micropenis had post HCG testosterone: DHT ratio of 7. A diagnosis of 5-ARD was subsequently made on urinary steroid profile and confirmed on genetic testing.

Conclusion: This series revealed that clitoromegaly and inguinal lumps were a common finding in females with 5-ARD. Thus females with a diagnosis of AIS were re-evaluated and subsequently 3 of them were reclassified as 5-ARD. Furthermore the post HCG testosterone: DHT ratio may not be diagnostic of 5-ARD. We reinforce the need to evaluate these children using a combination of USP, HCG test & genetics.