title: Genome-wide association study of rheumatoid arthritis in Koreans: population-specific loci as well as overlap with European susceptibility loci.
abstract: OBJECTIVE
  To perform a genome-wide association study (GWAS) in Koreans in order to identify susceptibility loci for rheumatoid arthritis (RA).
  
  
  METHODS
  We generated high-quality genotypes for 441,398 single-nucleotide polymorphisms (SNPs) in 801 RA cases and 757 controls. We then tested 79 markers from 46 loci for replication in an independent sample of 718 RA cases and 719 controls.
  
  
  RESULTS
  Genome-wide significance (P < 5 × 10(-08) ) was attained by markers from the major histocompatibility complex region and from the PADI4 gene. The replication data showed nominal association signals (P < 5 × 10(-02) ) for markers from 11 of the 46 replicated loci, greatly exceeding random expectation. Genes that were most significant in the replication stage and in the combined analysis include the known European RA loci BLK, AFF3, and CCL21. Thus, in addition to the previously associated STAT4 alleles, variants at these three loci may contribute to RA not only among Europeans, but also among Asians. In addition, we observed replication signals near the genes PTPN2, FLI1, ARHGEF3, LCP2, GPR137B, TRHDE, and CGA1. Based on the excess of small P values in the replication stage study, we estimate that more than half of these loci are genuine RA susceptibility genes. Finally, we systematically analyzed the presence of association signals in Koreans at established European RA loci, which showed a significant enrichment of European RA loci among the Korean RA loci.
  
  
  CONCLUSIONS
  Genetic risk for RA involves both population-specific loci as well as many shared genetic susceptibility loci in comparisons of Asian and European populations.
authors: Feinstein Institute for Medical Research and North Shore-Long Island Jewish Health System, Manhasset, New York, NY, USA.
authors: Jan
authors: J
authors: Freudenberg
authors: Hye-Soon
authors: HS
authors: Lee
authors: Bok-Ghee
authors: BG
authors: Han
authors: Hyoung Do
authors: HD
authors: Shin
authors: Young Mo
authors: YM
authors: Kang
authors: Yoon-Kyoung
authors: YK
authors: Sung
authors: Seung-Cheol
authors: SC
authors: Shim
authors: Chan-Bum
authors: CB
authors: Choi
authors: Annette T
authors: AT
authors: Lee
authors: Peter K
authors: PK
authors: Gregersen
authors: Sang-Cheol
authors: SC
authors: Bae
mesh_terms: D001172:Arthritis, Rheumatoid / Q000208:ethnology* / Q000235:genetics*; D016022:Case-Control Studies; D005060:Europe; D056426:Genetic Loci / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000208:ethnology* / Q000235:genetics*; D055106:Genome-Wide Association Study; D005838:Genotype; D006801:Humans; D007723:Korea; D020641:Polymorphism, Single Nucleotide / Q000235:genetics