DEFB1 encodes beta-defensin 1, an antimicrobial peptide with dual functions in innate immunity and cellular signaling. The protein exhibits bactericidal activity against both Gram-positive and Gram-negative bacteria, serving as a critical component of mucosal immunity 1. Beyond antimicrobial defense, DEFB1 acts as a signaling molecule that can trigger calcium mobilization and enhance cellular proliferation and migration, as demonstrated in keratinocytes where it contributes to skin barrier function 2. The gene shows significant clinical relevance through its genetic polymorphisms, which influence disease susceptibility across multiple conditions. The rs11362 polymorphism is associated with increased dental caries risk in permanent dentition 3 and periodontitis susceptibility 4. Various DEFB1 polymorphisms also modify vitiligo risk and treatment response, with certain genotypes providing protection while others increase susceptibility 56. Additionally, DEFB1 variants contribute to digestive disease susceptibility, including severe acute pancreatitis and Crohn's disease 7. The protein's expression levels are also clinically significant, with decreased circulating levels observed in vitiligo patients 6, suggesting its potential as a biomarker for autoimmune skin conditions.