FN1 and endometriosis: While Genome-Wide Association Studies (GWAS) have identified numerous susceptibility loci-such as <i>WNT4</i>, <i>FN1</i>, and <i>VEZT</i>-the functional translation of these genetic risks into phenotype-specific pathophysiology remains unclear.<h4>Objectives</h4>This systematic review aims to analyze the differential activation and expression patterns of known endometriosis-susceptibility genes across SUP, OMA, and DIE to determine if distinct genetic signatures define each phenotype.<h4>Methods</h4>A systematic search was conducted in PubMed, Scopus, and Embase up to September 2025.