DEFB127 (defensin beta 127) is an antimicrobial peptide with antibacterial activity that functions in innate immune defense against bacterial pathogens, particularly gram-negative bacteria 1. The gene encodes a component of the humoral antimicrobial immune response involved in defense mechanisms and protein binding interactions [GO annotations]. Evolutionary analysis reveals DEFB127 has undergone balancing selection in human populations, with two highly diverged haplotype clades carrying different variants at a codon that showed positive selection in catarrhine primates, suggesting long-term selective pressure 2. Clinically, DEFB127 promoter variants are emerging as disease-relevant loci: a promoter SNP (rs6055069) was identified as a novel genome-wide significant risk variant for coronary artery disease in type 1 diabetes (OR = 4.17, P = 2.35 × 10⁻⁹), providing a mechanistic link between infection susceptibility, diabetes, and cardiovascular disease 1. Additionally, the 20p13 chr20 region containing DEFB127 shows amplification in tongue cancer recurrence cases 3, and DEFB127 was among the most significantly mutated genes in pulmonary carcinoid tumors 4, suggesting potential involvement in neoplastic pathways. These findings indicate DEFB127 bridges innate immunity with metabolic and oncological disease susceptibility.