The first signal, led by rs140884539-C (P-value = 7.05×10<sup>-08</sup>, beta = 0.59), was in strong linkage disequilibrium with variants associated with predisposition to rheumatoid arthritis, decrease in dopamine, increased levels of GCH1 transcript, dopamine metabolites, and galectin-3. This evidence concerns the gene GCH1 and rheumatoid arthritis.