MON-273 Retrospective Analysis of Gonadotropin-Mediated Pubertal Induction in Male Patients with Congenital Hypogonadotropic Hypogonadism (CHH)

CHH is a rare disease characterized by a failure to enter (complete forms) or to complete (partial forms) pubertal development. It has a strong genetic background and it needs a treatment to allow the puberty to complete. In male this goal could be achieved either by the classic testosterone replacement therapy or by the exogenous gonadotropins (Gn) administration which allows both the endogenous testosterone production and the testicular development. So far, only few studies have explored this latter therapeutic approach in inducing the CHH pubertal development and no internationally recognized protocols are available. Aim of this retrospective analysis is to (i) investigate clinical and biochemical predictors of testicular response to Gn-induced puberty in CHH; (ii) study the non-reproductive outcomes of this treatment (height, body proportions) and their determinants. A total of 19 CHH male patients, undergoing two years of Gn-mediated (FSH and hCG) puberty induction started between the ages of 14 and 23 years, were retrospectively evaluated. For each patient clinical history, physical examination, hormonal evaluation, and genetic analysis using Targeted Next Generation Sequencing for CHH genes was performed; 8 patients accepted to perform a semen analysis (SA) at the end of their treatment.Mann Whitney test and multiple regression analysis showed testicular volume after 24 months of Gn-mediated pubertal induction, to be significantly associated with: (i) the presence of cryptorchidism; (ii) the presence of a completely definable genetic cause for the disease; (iii) the presence of a complete CHH form. No significant association was found with the cumulative dose of hCG administered in 24 months. The statistical analyses regarding SA could not find the same associations. Multiple regression analyses investigating the eunuchoid habitus and a measure of the difference of subject’s final height from his target (deltaSDSth), showed a significant association with: (i) age at the beginning of the induction; (ii) the duration of growth during induction; (iii) and (for deltaSDSth) bone age before the induction. Duration of growth during induction resulted to be associated with previous testosterone priming and with partial CHH.In summary, our study confirms cryptorchidism and complete genetic forms of CHH as negative predictors of testicular response probably because they usually affect early phases of life with a complete GnRH deficiency. We also found that the eunuchoid habitus and deltaSDSth are associated not only with delayed treatment, but also with the duration of stature growth during the induction, apparently related to earlier androgenization.