We carried out a genome-wide association study (GWAS) meta-analysis using 1975 anti-CCP+ RA patients from three large cohorts, the Brigham Rheumatoid Arthritis Sequential Study (BRASS), North American Rheumatoid Arthritis Consortium (NARAC) and the Epidemiological Investigation of RA (EIRA).
We created a weighted genetic risk score (GRS) and evaluated it as 7 ordinal groups using logistic regression (adjusting for age and smoking) to assess the relationship between GRS group and odds of developing seronegative (RF- and CCP-), seropositive (RF+ or CCP+), erosive, and seropositive, erosive RA phenotypes.
Significant enrichment of 187-Ile allele was observed in RA patients positive for anti-CCP antibodies as compared with the anti-CCP negative RA patients (P=0.001, OR 1.652 (95% CI 1.210-2.257)) or as compared with the normal controls (P=0.005, OR 1.348 (95% CI 1.092-1.664)).