Genetic Profiles and Three-year Follow-up Study of Chinese Males With Congenital Hypogonadotropic Hypogonadism

Background The correlation between long-term treatment outcomes with genotypes in congenital hypogonadotropic hypogonadism (CHH) males is rarely reported. Aim To investigate the correlations among genotypes, phenotypes, and treatment outcomes for CHH male patients. Methods Whole exome sequencing was performed for 73 Chinese CHH males from one academic center. Patients self-selected one of the 4 treatments: pulsatile Gonadorelin pump (PGP), cyclical gonadotropins therapy (CGT), human menopausal gonadotropin monotherapy, or testosterone replacement treatment. Clinical assessments were performed every 3 months for 3 years. Outcomes The pathogenicity of variants was determined. Baseline clinical features, spermatogenesis outcomes were analysed. RESULTS 62 variants were identified in 51 patients (69.9%), 17 of which were novel. Among these mutations, variants on FGFR1, PROKR2, CHD7, ANOS1 and NSMF gene were 16.1%, 16.1%, 11.3%, 8.1% and 8.1% respectively. 11 patients followed the oligogenic pattern (21.6%). All CHD7 patients had hearing impairment or structural deformities of external/inner ear, and were diagnosed as CHARGE syndrome. 24.7% of CHH patients manifested with ear/hearing anomalies. KS patients had higher rates of cryptorchidism history and ear/hearing anomalies than normosmic CHH subjects. Male patients with PROKR2 mutations showed relatively better testicular development, less dental deformity when compared with FGFR1 mutations. About 30% normosmic patients defined by simple olfactory assessment showed olfactory nerve center (ONC) dysplasia under nasal sinus MRI examination. Among the CHH males treated with CGT or PGP, 70.2% reached spermatogenesis within 3 years of treatment. Clinical Implications No direct correlation was observed between certain responsible genes and spermatogenic outcomes. When CHH patients were identified with CHD7 variants, ear/hearing evaluation should be carefully performed. The precise assessment of ONC development was advised for normosmic CHH subjects. Strengths & Limitations This study provided informative long-term treatment data of CHH male patients screened with whole exome sequencing. The limitations included small number of subgroups with multifaceted gene variants, clinical heterogeneity, and uncontrolled sperm-inducing treatment method. The seventeen novel mutations worth experimental validation in the future. CONCLUSION The clinical severity is partially related with specific gene variants, and detailed individualized data and outcomes were provided. Ear/hearing anomalies were closely connected with CHD7 variants, and were common problems for CHH patients. Simple olfactory assessment underestimated the true olfactory deficit.