There were no statistically significant differences between the serum proBDNF levels (464 ± 583 pg/mL vs. 372 ± 487 pg/mL; p = 0.328) and proBDNF/BDNF ratio (0.03 ± 0.05 vs. 0.04 ± 0.09; p = 0.370) between patients with RA and controls (Figure 1). This evidence concerns the gene BDNF and rheumatoid arthritis.