title: Assessment of gene-covariate interactions by incorporating covariates into association mapping.
abstract: The HLA region is considered to be the main genetic risk factor for rheumatoid arthritis. Previous research demonstrated that HLA-DRB1 alleles encoding the shared epitope are specific for disease that is characterized by antibodies to cyclic citrullinated peptides (anti-CCP). In the present study, we incorporated the shared epitope and either anti-CCP antibodies or rheumatoid factor into linkage disequilibrium mapping, to assess the association between the shared epitope or antibodies with the disease gene identified. Incorporating the covariates into the association mapping provides a mechanism 1) to evaluate gene-gene and gene-environment interactions and 2) to dissect the pathways underlying disease induction/progress in quantitative antibodies.
authors.affiliation: Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County 350, Taiwan, Republic of China. yfchiu@nhri.org.tw.
authors.forename: Yen-Feng
authors.initials: YF
authors.lastname: Chiu
authors.forename: Hui-Yi
authors.initials: HY
authors.lastname: Kao
authors.forename: Yi-Shin
authors.initials: YS
authors.lastname: Chen
authors.forename: Fang-Chi
authors.initials: FC
authors.lastname: Hsu
authors.forename: Hsin-Chou
authors.initials: HC
authors.lastname: Yang