Because the roles of the NIN and SIGLEC5 genes in periodontitis susceptibility in Han Chinese individuals have not previously been evaluated, we performed a case-control study to assess the relationship of the NIN and SIGLEC5 genes with periodontitis susceptibility in Han Chinese individuals to improve our current understanding of the roles of these genes in periodontitis predisposition. This evidence concerns the gene SIGLEC5 and periodontitis.