Omics-driven insights into the genetic architecture of male infertility

Male infertility is a multifactorial disorder affecting approximately 15% of couples worldwide and contributing to nearly 50% of infertility cases among couples. Genetic abnormalities are major determinants of male infertility, particularly in severe and idiopathic forms, and include chromosomal abnormalities, copy number variations (CNVs), Y chromosome microdeletions and monogenic variants affecting spermatogenesis, sperm motility and morphology. However, at least 40% of all cases remain classified as idiopathic. Recent advances in Next Generation Sequencing (NGS) technologies, including Clinical Exome Sequencing (CES), enabled the simultaneous analysis of thousands of genes associated with male infertility, improving the understanding of its molecular basis. This study aims to expand current knowledge of the genetic architecture of male infertility and to contribute to the identification of novel candidate genes and molecular mechanisms involved in reproductive dysfunction through omics-based approaches, including Chromosomal Microarray Analysis (CMA) and NGS. In this context, male patients undergoing fertility treatments in the IVF Unit of the General Hospital “G. Bernabeo” (Ortona, Italy) were referred to the Unit of Medical Genetics at the Center for Advanced Studies and Technology (CAST) of the “G. d’Annunzio” University of Chieti-Pescara to investigate the potential genetic causes underlying idiopathic or severe forms of male infertility through advanced molecular and genomic analyses. An initial cohort of 160 male patients with idiopathic infertility was selected with negative result for CFTR first-level testing and Y chromosome microdeletions. All enrolled individuals subsequently underwent conventional cytogenetic analyses (karyotyping), which revealed the presence of chromosomal abnormalities and structural rearrangements in a subset of patients, potentially associated with impaired spermatogenesis and reproductive dysfunction. CMA analysis was employed to investigate patients with ambiguous karyotypes and analyses are currently undergoing. Subsequently, a cohort of 30 patients presenting severe infertility phenotypes, despite negative results from previous genetic investigations, was selected for further molecular and omics characterization through CES. The analysis is currently ongoing on the Illumina NextSeq™ 550Dx platform to identify potentially causative genes associated with spermatogenesis, meiosis, sperm motility, morphology and other reproductive pathways. Data interpretation and genotype–phenotype correlation analyses are currently in progress. In conclusion, obtained results and ongoing experiments may contribute to better comprehend the molecular signature behind male infertility and help optimize prevention strategies.