title: Genomewide association study on chronic periodontitis in Korean population: results from the Yangpyeong health cohort.
abstract: OBJECTIVE
  This study aims to locate the genes related to periodontitis through genome-wide association study (GWAS) in Korean population.
  
  
  METHODS
  Total of 677 adults aged 44-88 years were recruited from the Yangpyeong cohort in Korea. The participants did not have self-reported metabolic diseases, cardiovascular diseases or cancer. Periodontitis was assessed using alveolar bone loss from a digital panoramic radiograph and classified into three groups: normal to mild, moderate and severe periodontitis. DNA from blood samples were genotyped using the Illumina Human 1M-duo Beadchip. Multivariable logistic regression analysis in PLINK was applied to examine the single-nucleotide polymorphisms (SNPs) related to periodontitis after controlling for various confounders.
  
  
  RESULTS
  Associations of three SNPs suggested TENM2 (rs4242220) and LDLRAD4 (rs12969041, rs2027756) as putative risk genes of chronic periodontitis (p-values <1 × 10-5). The odds ratio [95% confidence interval (CI)] of TENM2 was 0.53 (0.40-0.70) for moderate periodontitis and that of LDLRAD4 was 2.86 (1.92-4.27) for severe periodontitis. Two nonsynonymous SNPs of protein coding region and seven SNPs selected from previous reports showed nominal association.
  
  
  CONCLUSIONS
  Our GWAS supports a previously reported gene of TENM2 and newly suggests LDLRAD4. These two genes' role on lipid metabolism may play a part in the molecular aetiology of periodontitis.
authors.affiliation: Theragen Etex Bio Institute, Suwonsi, Gyeonggi-do, Korea.|Division of Biomedical Informatics, Center for Genome Science, National Institute of Health, KCDC, Cheongju-si, Chungbuk, Korea.
authors.forename: Kyung-Won
authors.initials: KW
authors.lastname: Hong
authors.affiliation: Department of Preventive and Social Dentistry, School of Dentistry, Seoul National University, Daehak-ro, Seoul, Korea.
authors.forename: Myung-Seop
authors.initials: MS
authors.lastname: Shin
authors.affiliation: Department of Preventive and Social Dentistry, School of Dentistry, Seoul National University, Daehak-ro, Seoul, Korea.
authors.forename: Yoo-Been
authors.identifier: http://orcid.org/0000-0002-7154-852X
authors.initials: YB
authors.lastname: Ahn
authors.affiliation: Department of Preventive and Social Dentistry, School of Dentistry, Seoul National University, Daehak-ro, Seoul, Korea.
authors.forename: Hyun-Jin
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Preventive and Social Dentistry, School of Dentistry, Seoul National University, Daehak-ro, Seoul, Korea.|Dental Research Institute, School of Dentistry, Seoul National University, Daehak-ro, Seoul, Korea.
authors.forename: Hyun-Duck
authors.initials: HD
authors.lastname: Kim
keywords: Korean; epidemiology; genome-wide association studies; periodontitis; single-nucleotide polymorphisms