Footnotes

• Funding This study was funded by the National Institutes of Health. NIH N01-AR-6-2278 Continuation of the Consortium for the Longitudinal Evaluation of African-Americans with Early Rheumatoid Arthritis (CLEAR) Registry.

• Competing interests None.

• Patient consent Obtained.

• Ethics approval This study was conducted with the approval of the institutional review board of each participating institution.

• Provenance and peer review Not commissioned; externally peer reviewed.

  Between the time this manuscript was accepted for publication and the time of review of the proofs, we performed genotyping on SNP rs11889341 T/C in the STAT4 gene (this SNP is a proxy SNP for STAT4 rs7574865). A total of 556 African-Americans with autoantibody-positive RA (defined as a positive serum rheumatoid factor or a positive serum anti-cyclic citrullinated peptide antibody) and 804 healthy African-American controls was genotyped. All cases and controls in this current report were analysed in our subsequent analysis. The minor allele frequency of MAF in cases was 0.15 and in controls was 0.13 (p value 0.071; OR 1.22, 95% CI 0.98 to1.53). We had limited statistical power in this analysis, but it seems likely that, with the inclusion of additional autoantibody-positive African-Americans with RA, this SNP will be statistically significantly associated with RA at a similar OR.