BACKGROUND: Genetic factors have a substantial role in determining development 
of rheumatoid arthritis (RA), and are likely to account for 50-60% of disease 
susceptibility. Genome-wide association studies have identified non-human 
leucocyte antigen RA susceptibility loci which associate with RA with 
low-to-moderate risk.
OBJECTIVES: To investigate recently identified RA susceptibility markers using 
cohorts from six European countries, and perform a meta-analysis including 
previously published results.
METHODS: 3311 DNA samples were collected from patients from six countries (UK, 
Germany, France, Greece, Sweden and Denmark). Genotype data or DNA samples for 
3709 controls were collected from four countries (not Sweden or Denmark). 
Eighteen single nucleotide polymorphisms (SNPs) were genotyped using Sequenom 
MassArray technology. Samples with a >95% success rate and only those SNPs with 
a genotype success rate of >95% were included in the analysis. Scandinavian 
patient data were pooled and previously published Swedish control data were 
accessed as a comparison group. Meta-analysis was used to combine results from 
this study with all previously published data.
RESULTS: After quality control, 3209 patients and 3692 controls were included in 
the study. Eight markers (ie, rs1160542 (AFF3), rs1678542 (KIF5A), rs2476601 
(PTPN22), rs3087243 (CTLA4), rs4810485 (CD40), rs5029937 (6q23), rs10760130 
(TRAF1/C5) and rs7574865 (STAT4)) were significantly associated with RA by 
meta-analysis. All 18 markers were associated with RA when previously published 
studies were incorporated in the analysis. Data from this study increased the 
significance for association with RA and nine markers.
CONCLUSIONS: In a large European RA cohort further evidence for the association 
of 18 markers with RA development has been obtained.