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

AimTo identify loci associated with chronic periodontitis through a genome-wide association study (GWAS). Materials and MethodsA 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. ResultsNo genome-wide significant associations were found for any periodontitis case definition, regardless of whether individuals aged >60years 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 >60years increased the explained variance to 34%. ConclusionsNo single SNPs were found to be genome-wide significantly associated with chronic periodontitis in this study.