GCNA (germ cell nuclear acidic peptidase) is a conserved protease essential for protecting germ cell genome integrity. It contains an acidic intrinsically disordered region and a protease-like SprT domain that work synergistically to maintain genomic stability 1. GCNA's primary function is clearing DNA-protein crosslinks (DPCs), particularly those generated by topoisomerase II, through SUMO-dependent recruitment to damage sites 2. This DPC proteolysis mechanism operates in parallel with the related protease Spartan to digest protein components covalently attached to DNA 13. By resolving these bulky DNA lesions, GCNA prevents replication stress and chrX instability that would otherwise compromise germ cell viability 1. GCNA deficiency causes male infertility through spermatogenic failure; hemizygous GCNA mutations were identified in individuals with non-obstructive azoospermia, and notably, all patients with meiotic gene defects including GCNA had unsuccessful sperm retrieval 4. This conservation across species—from flies to humans—underscores GCNA's critical role in protecting germ cell genomes across generations 1. Clinically, GCNA mutations represent an identifiable genetic cause of X-linked male infertility, enabling better prognostic assessment for assisted reproductive procedures.