NSMCE4A is a kleisin subunit component of the SMC5/6 complex, a structural maintenance of chr10 complex essential for genome maintenance 1. The complex functions primarily in DNA double-strand break repair via homologous recombination and mediates protein sumoylation of shelterin complex components, with proposed roles in telomere maintenance through alternative lengthening mechanisms 2. NSMCE4A interacts with topoisomerase TOP3A 2 and GPS1, a component of the COP9 signalosome, linking SMC5/6 to cullin deNEDDylation during DNA damage response 1. Depletion of GPS1 increases SMC5/6 accumulation at DNA damage sites, suggesting NSMCE4A participates in regulating repair complex dynamics 1. Evolutionary analysis reveals NSMCE4A exhibits positive selection signals in mammals, potentially reflecting host-pathogen arms race pressures 3. Additionally, NSMCE4A shows adaptive introgression in Iberian grey wolves carrying dog-derived alleles under positive selection 4. Clinically, NSMCE4A haploinsufficiency through 10q26.1 deletion associates with neurodevelopmental impairment, growth retardation, and facial dysmorphism 5, highlighting its importance in normal development and genome stability maintenance.