title: Assessment of chromosome 19 for genetic association in severe chronic periodontitis.
abstract: BACKGROUND
  A genome-association study is a powerful tool for analyzing small gene effects in complex diseases such as chronic periodontitis (CP), although the cost of analysis is prohibitive. We designed a study using the DNA pooling method, which could be a breakthrough in lowering such costs. This study was conducted to assess the genetic association in severe CP in a Japanese population.
  
  
  METHODS
  We adopted a DNA pooling method by genotyping 454 densely spaced microsatellite (MS) markers in chromosome 19 as a pilot study, with the possibility of future use in a whole-genome study. This can reduce the high cost and technical burden, which is generally unavoidable in a genomic association study. Pooled DNA samples from 300 case subjects, 300 control subjects, and 200 systemically healthy subjects were screened by genotyping MS markers. The case-control association in the candidate region was analyzed by individual typing of MS and single nucleotide polymorphisms (SNPs).
  
  
  RESULTS
  The single MS marker allele 17 of 1902G31 was isolated in association with severe CP (P = 0.0012 for 2 x 2; P <0.046 for 2 x m, where m refers to the number of polymorphic alleles observed in a population). No other SNP or MS polymorphism hypothesized to affect biologic functions in the critical region was found in the linkage disequilibrium block analysis.
  
  
  CONCLUSIONS
  We efficiently isolated the susceptible locus for severe CP in chromosome 19 and identified a useful marker to evaluate the risk for disease. This approach can be applied to a whole-genome study in severe CP.
authors.affiliation: Center for Transdisciplinary Research, Niigata University, Niigata, Japan. koichi@dent.niigata-u.ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Tabeta
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Shimada
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tai
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ishihara
authors.forename: Toshihide
authors.initials: T
authors.lastname: Noguchi
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Soga
authors.forename: Shogo
authors.initials: S
authors.lastname: Takashiba
authors.forename: Genki
authors.initials: G
authors.lastname: Suzuki
authors.forename: Terukazu
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Akira
authors.initials: A
authors.lastname: Oka
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Inoko
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Yoshie