Genome‐wide association study of chronic periodontitis in a general German population

AIM: To identify loci associated with chronic periodontitis through a genome-wide association study (GWAS). MATERIALS AND METHODS: A GWAS was performed in 4032 individuals of two independent cross-sectional studies of West Pomerania (SHIP n = 3365 and SHIP-TREND n = 667) with different periodontal case definitions. Samples were genotyped with the Affymetrix Genome-Wide Human SNP Array 6.0 or the Illumina Human Omni 2.5 array. Imputation of the HapMap as well as the 1000 Genome-based autosomal and X-chromosomal genotypes and short insertions and deletions (INDELs) was performed in both cohorts. Finally, more than 17 million SNPs and short INDELs were analysed. RESULTS: No genome-wide significant associations were found for any periodontitis case definition, regardless of whether individuals aged >60 years where excluded or not. Despite no single SNP association reached genome-wide significance, the proportion of variance explained by additive effects of all common SNPs was around 23% for mean proximal attachment loss. Excluding subjects aged >60 years increased the explained variance to 34%. CONCLUSIONS: No single SNPs were found to be genome-wide significantly associated with chronic periodontitis in this study.