Analysis of mutations of inflammatory cytokine and Toll-like receptor genes in periodontitis in Down syndrome patients

Periodontitis is a widespread and serious dental disease that results from multifactorial and lifestyle-related causes. Patients with Down syndrome have a high risk of periodontal disease from an early age, but little is known about the genetic factors that may cause or exacerbate it. With this regard, we isolated DNAs from lingual mucosal cells and examined the frequency of specific single nucleotide polymorphisms (SNPs) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The SNPs on which we focused were of the pro-inflammatory cytokine genes Interleukin (IL)-1A(−889) and IL-1B(+3953), and of the Toll-like receptor genes (TLR)2(Arg677Trp) and TLR4(Asp299Gly). The subjects of the study, all of Japanese extraction, were: (i) 18 individuals with Down syndrome and periodontitis; (ii) 10 individuals with Down syndrome and no periodontitis; (iii) 20 control individuals without Down syndrome but with periodontitis; and (iv) 10 control individuals without periodontitis. The patterns of occurrence of SNPs of the IL-1A, IL-1B, TLR2 and TLR4 were similar in all groups.