GCC2 and rheumatoid arthritis: Finally, two-sample Mendelian randomization (MR) was performed to assess causal relationships between key genes and RA.<h4>Results</h4>A total of 521 BS-UGs and 21 candidate BS-TUGs were identified, from which six key genes (DOCK10, DGKA, NOP58, JAK3, GCC2, ANO9) were selected.