Table 1.
RA study cohorts used for CLEC16A analyses
| RA1 | Controls | RA2 | Controls | |
|---|---|---|---|---|
| N | 682 | 752 | 1860 | 1458 |
| Site | NA | NA | UK | UK |
| Mean age (years) | 56.2 | 48.5 | — | — |
| Age range (years) | 21–87 | 30–82 | — | <70 |
| Female, N (%) | 503 (73.7) | 525 (69.8) | 1390 (74.7) | 753 (51.6) |
| Mean age-at-onset (years) | 45.7 | — | ||
| Rheumatoid factor positive, N (%) | 580 (85) | 1310 (83.9) | ||
| 0 | 15 (2.3) | 401 (53.3) | 286 (20.7) | |
| 1 | 362 (56.5) | 301 (40) | 680 (49.2) | |
| 2 | 264 (41.2) | 50 (6.6) | 416 (30.1) | |
| Erosions, N (%) | 211 (66.6) | — | ||
| Anti-CCP positive, N (%) | 681 (100) | 884 (79.8) |
RA cases met the American College of Rheumatology classification criteria for RA.45 RA2 controls were a subset of the WTCCC T1D GWA study controls.19 RA1 controls were frequency matched by age and gender to the cases. RA2 controls were frequency matched by geographical region and gender to the 1958 Birth cohort (which included all births in England, Wales and Scotland, during one week in 1958) so as to be nationally representative. On the basis of the available genetic ancestry data for all individuals, and to apply the most stringent criteria possible for genetic analysis of CLEC16A, only RA1 subjects with ≥90% Northern European ancestry and RA2 subjects with European ancestry were analyzed. European ancestry was estimated in RA1 using a Bayesian clustering algorithm (Structure v. 2.0, Oxford, UK) and data for 112 European and 246 Northern European ancestry informative markers.46,47 For RA2, European ancestry was estimated by principal components analysis.19
HLA-DRB1*0101, *0102, *0104, *0401, *0404, *0405, *0408, *0413, *0416, *1001 alleles.