Moreover, single nucleotide polymorphisms genome studies revealed differences in the allele frequencies in the Tumor Necrosis Factor receptor (TNFR) genes (TNFRSF1A and TNFRSF1B) between AA (healthy and with RA) and Caucasians, suggesting that these differences could imply higher likelihood to develop RA, influence disease severity and response to biologics [12]. This evidence concerns the gene TNFRSF1A and rheumatoid arthritis.