Comparison of Clinical Characteristics and Spermatogenesis in CHH Patients Caused by PROKR2 and FGFR1 Mutations.

A retrospective study was conducted to investigate the effect of gonadotropin or pulsatile gonadotropin-releasing hormone (GnRH) therapy on spermatogenesis in congenital hypogonadotropic hypogonadism (CHH) patients with PROKR2 (prokineticin receptor 2) or FGFR1 (fibroblast growth factor receptor 1) mutations. Clinical features, gonadotropin levels, testicular volume (TV), and sperm concentration in response to gonadotropin and pulsatile GnRH therapy were compared between groups with PROKR2 and FGFR1 mutations. Twelve patients with PROKR2 gene mutation and fourteen patients with FGFR1 gene mutation were included. The incidence of cryptorchidism in PROKR2 and FGFR1 groups was 16.7% and 50%, respectively (p = 0.110). The baseline TV in the PROKR2 group was larger than that in FGFR1 group (2.0 vs. 1.63, p = 0.047). The initial LH, FSH, and testosterone levels were similar between the two groups. Based on the analysis of achieving spermatogenesis using Kaplan-Meier and log-rank tests, the PROKR2 group demonstrated shorter period of seminal spermatozoa appearance than the FGFR1 group (χ2 = 8.297, p = 0.004); the median duration of achieving spermatogenesis in the PROKR2 and FGFR1 groups was 9 and 16 months, respectively. The PROKR2 mutation group exhibited shorter required time to achieve different sperm concentration thresholds (5, 10, and 15 million/mL) than the FGFR1 mutation group (p = 0.012, 0.024, and 0.040). In conclusion, the PROKR2 group achieved spermatogenesis easily than the FGFR1 group, possibly due to the lower prevalence of cryptorchidism and larger baseline testicular volume in the PROKR2 group.