A 21-year-old male is referred to the endocrine clinic with poorly developed secondary sexual characteristics. The only relevant finding on history is that he has a very poor sense of smell.
On examination he has no axillary or pubertal hair, a 3 cm penis and testicular volumes of approximately 5 ml bilaterally. Smell test reveals that he is unable to distinguish acetone and coffee.
What is the most likely diagnosis?
(Please select 1 option)
|5-alpha reductase deficiency|
|Kallman’s syndrome This is the correct answer|
|Microdeletion of the Y chromosome Incorrect answer selected|
This patient has evidence of hypogonadotrophic hypogonadism with a low testosterone and a low follicle-stimulating hormone (FSH) and luteinising hormone (LH). In this case, there is isolated gonadotrophic deficiency as evidenced by a normal prolactin. This is seen in Kallman’s syndrome, which is often associated with anosmia.
In Klinefelter’s syndrome an elevated LH/FSH would be expected, as this is due to testicular failure as would be the case in 5-alpha reductase deficiency.
Craniopharyngioma is a possibility as it does cause hypogonadotrophic hypogonadism but abnormalities in sense of smell would not be expected.