title: Genome-wide association study of chronic periodontitis in a general German population.
abstract: OBJECTIVE
  To identify loci associated with chronic periodontitis through a genome-wide association study (GWAS).
  
  
  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.
authors.affiliation: Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Teumer
authors.forename: Birte
authors.initials: B
authors.lastname: Holtfreter
authors.forename: Uwe
authors.initials: U
authors.lastname: Völker
authors.forename: Astrid
authors.initials: A
authors.lastname: Petersmann
authors.forename: Matthias
authors.initials: M
authors.lastname: Nauck
authors.forename: Reiner
authors.initials: R
authors.lastname: Biffar
authors.forename: Henry
authors.initials: H
authors.lastname: Völzke
authors.forename: Heyo K
authors.initials: HK
authors.lastname: Kroemer
authors.forename: Peter
authors.initials: P
authors.lastname: Meisel
authors.forename: Georg
authors.initials: G
authors.lastname: Homuth
authors.forename: Thomas
authors.initials: T
authors.lastname: Kocher
mesh_terms: D000225:Adenine; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D041321:Chromosomes, Human, X / Q000235:genetics; D055113:Chronic Periodontitis / Q000235:genetics*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003596:Cytosine; D005260:Female; D005500:Follow-Up Studies; D014644:Genetic Variation / Q000235:genetics; D055106:Genome-Wide Association Study; D005838:Genotype; D005858:Germany; D060148:HapMap Project; D006801:Humans; D054643:INDEL Mutation / Q000235:genetics; D008297:Male; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000235:genetics; D010514:Periodontal Pocket / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011159:Population Surveillance; D013941:Thymine; D055815:Young Adult
chemical_list: D003596:Cytosine; D000225:Adenine; D013941:Thymine
keywords: Study of Health in Pomerania; attachment loss; genome-wide association studies; periodontitis