Dr. Gregersen is a member of the Abbott Scholar Scientific Review Board and receives consulting fees (more than $10,000) from Abbott.
Dissecting the heterogeneity of rheumatoid arthritis through linkage analysis of quantitative traits
Article first published online: 28 DEC 2006
Copyright © 2006 by the American College of Rheumatology
Arthritis & Rheumatism
Volume 56, Issue 1, pages 58–68, January 2007
How to Cite
Criswell, L. A., Chen, W. V., Jawaheer, D., Lum, R. F., Wener, M. H., Gu, X., Gregersen, P. K. and Amos, C. I. (2007), Dissecting the heterogeneity of rheumatoid arthritis through linkage analysis of quantitative traits. Arthritis & Rheumatism, 56: 58–68. doi: 10.1002/art.22325
- Issue published online: 2 JAN 2007
- Article first published online: 28 DEC 2006
- Manuscript Accepted: 6 OCT 2006
- Manuscript Received: 13 JAN 2006
- NIH. Grant Numbers: K24-AR-02175, ES-09912
- North American Rheumatoid Arthritis Consortium was supported by the National Arthritis Foundation
- National Institute of Allergy and Infectious Diseases. Grant Number: N01-AR-72232
- National Institute of Arthritis and Musculoskeletal and Skin Diseases. Grant Number: R01-AR-44222
- General Clinical Research Center, Moffitt Hospital, University of California, San Francisco
- NIH National Center for Research Resources from the USPHS. Grant Number: 5-M01-RR-00079
To dissect the heterogeneity of rheumatoid arthritis (RA) through linkage analysis of quantitative traits, specifically, IgM rheumatoid factor (IgM-RF) and anti–cyclic citrullinated peptide (anti-CCP) autoantibody titers.
Subjects, 1,002 RA patients from 491 multiplex families recruited by the North American RA Consortium, were typed for 379 microsatellite markers. Anti-CCP titers were determined based on a second-generation enzyme-linked immunosorbent assay, and IgM-RF levels were quantified by immunonephelometry. We used the Merlin statistical package to perform nonparametric quantitative trait linkage analysis.
For each of the quantitative traits, evidence of linkage, with logarithm of odds (LOD) scores of >1.0, was found in 9 regions. For both traits, the strongest evidence of linkage was for marker D6S1629 on chromosome 6p (LOD 14.02 for anti-CCP and LOD 12.09 for RF). Six other regions with LOD scores of >1.0 overlapped between the 2 traits, on chromosomes 1p21.1, 5q15, 8p23.1, 16p12.1, 16q23.1, and 18q21.31. Evidence of linkage to anti-CCP titer but not to RF titer was found in 2 regions (chromosomes 9p21.3 and 10q21.1), and evidence of linkage to RF titer but not to anti-CCP titer was found in 2 regions (chromosomes 5p15.2 and 1q42.3). Several covariates were significantly associated with 1 or both traits, and linkage analysis exploring the covariate effects revealed striking effects of sex in modulating linkage signals for several chromosomal regions. For example, sex had a striking impact on the linkage results for both quantitative traits on chromosome 6p (P = 0.0007 for anti-CCP titer and P = 0.0012 for RF titer), suggesting a sex–HLA region interaction.
Analysis of quantitative components of RA is a promising approach for dissecting the genetic heterogeneity of this complex disorder. These results highlight the potential importance of sex or other covariates that may modulate some of the genetic effects that influence the risk of specific disease manifestations.