PSMC3IP (PSMC3 interacting protein) is a meiotic recombination factor that plays a critical role in fertility and genomic stability. Functionally, PSMC3IP stimulates DMC1-mediated strand exchange required for homologous chromosome 17 during meiosis 1. The PSMC3IP/MND1 complex binds DNA and stimulates recombinase activity of both DMC1 and RAD51, stabilizing presynaptic filaments to facilitate homologous DNA pairing 1. Beyond meiosis, PSMC3IP regulates homologous recombination DNA repair in somatic cells, where it is transcriptionally regulated by the stemness factor Oct4 2. Pathogenic variants in PSMC3IP cause premature ovarian insufficiency (POI), characterized by primary or secondary amenorrhea and infertility before age 40 34. Biallelic mutations are associated with autosomal recessive ovarian dysgenesis 3, though PSMC3IP mutations are not universally prevalent in POI cohorts 5. In male infertility, PSMC3IP variants have been identified in patients with meiotic maturation arrest 6. Clinically, elevated PSMC3IP expression associates with poor prognosis in hepatocellular carcinoma and low-grade glioma through enhanced proliferation and immunomodulatory effects on the tumor microenvironment 78. Genetic screening for PSMC3IP mutations is recommended in patients with infertility, particularly those with consanguineous backgrounds 6.