AbstractAimsThe role of genetic variations in genes related to innate response, as β‐defensin‐1 (DEFB1), in the context of chronic periodontitis (CP) and diabetes mellitus type 2 (DM2), is still not clear. The present study evaluates the distribution of DEFB1 single nucleotide polymorphisms (SNPs) 5′‐untranslated (5′UTR) region and its relation with the CP in DM2 individuals in northeastern Brazilians.MethodsTwo hundred and eighty individuals participated in the study, being 116 DM2+CP, 95 CP, and 69 healthy individuals. Three known DEFB1 functional SNPs [‐52 G > A (rs1799946), ‐44 C > G (rs1800972), ‐20 G > A (rs11362)] were genotyped with allele‐specific assays.ResultsAssociation was found for the DEFB1 ‐20 G > A SNP. The G allele, the GA and GG genotypes were significantly (P < 0.05) more frequent in the DM2+CP (59.5%, 50%, and 34.5%, respectively) and CP (61%, 44.2%, and 38.9%, respectively) than in healthy individuals (26.8%, 36.2%, and 8.7%, respectively). The GCG and ACG combinations (‐52, ‐44, ‐20) were significantly more frequent among DM2+CP and CP than in the healthy individuals.ConclusionThe results indicate that genetic variations of DEFB1 gene (SNP‐20: G allele and GA and GG genotypes) and the DEFB1 5′UTR haplotypes (GCG and ACG) may be associated with a susceptibility to CP in DM2 individuals as well as CP individuals without DM2.