Endocrine Abstracts

Congenital hypogonadotropic hypogonadism (HH) is characterized by deficient secretion and/or action of GnRH. The combination of hyposmia/anosmia and HH is termed Kallmann syndrome (minimal incidence estimate for men 1:30 000 and 1:125 000 in women, Laitinen et al. OJRD 2011), and, when the sense of smell is intact, normosmic HH (nHH). Even 10% of CHH patients may undergo reversal of hypogonadotropism after the age of 20 yrs (Raivio T et al. NEJM 2007), and the most apparent clinical sign suggesting reversal is an increase in testis size while on testosterone therapy. The triggers for HH reversal are unknown, but androgen exposure appears to play a role (Raivio T et al. NEJM 2007). We have verified a relatively high frequency of HH reversal among Finnish CHH males after testosterone withdrawal (Laitinen et al., submitted). Molecular genetic diagnoses were obtained for a high proportion of reversal variants, and these findings, and the need to follow-up reversal variants will be discussed. In conclusion, a short cessation of testosterone therapy to assess reversal of CHH is recommended to patients with spontaneous testis growth. It should be acknowledged, however, that a short cessation of testosterone therapy is different from poor long-term treatment compliance, which may lead to co-morbidities such as decreased bone health (Laitinen et al. Int J Androl 2011).

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: Declaration of Funding: Academy of Finland, Emil Aaltonen Foundation, Foundation for Pediatric Research, HUCH research funds.