DNA Methylation in Kallmann Syndrome: Impacts on Neuronal Development and Spermatogenesis.

Objective: This study aims to comprehensively characterize the DNA methylation profile in the sperm of patients with Kallmann Syndrome (KS), providing new insights into the potential epigenetic mechanisms contributing to the pathogenesis of the disease.

Methods: Sperm samples from patients with KS and Healthy Controls (HCs) were analyzed for DNA methylation patterns. Differentially methylated regions (DMRs) were identified, and the associated genes underwent enrichment analysis. Spermatogenesis-related genes were screened, analyzed for functional enrichment, and key genes were identified using the STRING database and CytoHubba. Their correlations with semen parameters were then evaluated.

Results: This study analyzed six patients with KS and six age-matched HCs, revealing higher DNA methylation in patients with KS. 4,749 DMRs were identified (4,020 hypermethylated, 729 hypomethylated), affecting genes linked to neuronal function, migration, and gonadotropin-releasing hormone (GnRH) secretion. DMRs were also observed in key KS-related genes, including CHD7, DCC, IL17RD, NELFA, and SEMA3E. Moreover, 1,938 spermatogenesis-related genes were identified within the gene body, with significant enrichment in chromosome remodeling pathways. Notably, core spermatogenesis genes such as BRCA1, H3FC3 and HSP90AA1 exhibited significant correlations with semen parameters.

Conclusion: This study identified DNA methylation changes in patients with KS after gonadotropin or pulsatile GnRH therapy, reflecting downstream epigenetic consequences of congenital gonadotropin deficiency and its treatment. These alterations are associated with persistent spermatogenic abnormalities, providing a foundation for future studies on epigenetic biomarkers and potential interventions.