rs10818488

rs10818488, a SNP located in between the C5 and TRAF1 genes, was identified as the SNP from this region showing maximal association with rheumatoid arthritis in a study of ~2000 Dutch, Swedish, and American patients. This study also reported that this SNP was significantly (p = 0.008) associated with increased disease progression as determined by radiographic damage over time in rheumatoid arthritis patients. The risk allele for rs10818488 is the minor allele, (A). If (and as) reported from just the Dutch RA patients, the odds ratio associated with rs10818488(A;G) heterozygotes is 1.38 (CI 1.04-1.83, p = 0.027) and with rs10818488(A;A) homozygotes 2.06 (95% CI 1.42-2.98, p = 1.29E-3). Combining data from all 2,000 patients, the odds ratio associated with rs10818488(A) is 1.26 (CI 1.15-1.37, pcombined = 1.40E-8) with a population attributable fraction (or risk) of 6.1% (CI 4.0-8.5). A study of RA patients from Crete also found that the rs10818488(A) allele represented increased risk for rheumatoid arthritis. A further study of 1,356 western Europeans confirmed the association between the rs10818488(A) allele and rheumatoid arthritis, finding that individuals with this allele have a 1.2x increased risk for the disease (CI: 1.04-1.5). The rs10818488(A) allele was associated with the susceptibility to rheumatoid factor-negative polyarthritis with an 11% increase in allele frequency (OR 1.54, CI: 1.09 to 2.18, p = 0.012) in a study of 338 Caucasian patients with juvenile idiopathic arthritis. Note that rs10818488 is reported to be in complete (100%) linkage disequilibrium with rs2416808, in other words, the genotype of one perfectly predicts the other.