In particular, −251(T/A), +396(T/G) and +781(C/T) polymorphisms in the IL-8 gene, forming the haplotype ATC/TTC is associated with periodontal disease and carriers of this haplotype had 2 times higher disease susceptibility than the other haplotypes, such as the ATT/TTC, which was not associated with susceptibility to periodontal disease20. The gene discussed is CXCL8; the disease is periodontal disorder.