Our study analyzed the effect of genetic variations in 5’ UTR (rs11362 (-20G>A), rs1800972 (-44C>G), and rs1799946 (-52G>A)) of the DEFB1 gene on the susceptibility to periodontitis associated with T2DM in the south Indian population and their influence on gene expression. The gene discussed is DEFB1; the disease is type 2 diabetes mellitus.