Validation through quantitative real-time PCR (qRT-PCR), Western blot, and immunofluorescence (IF) confirmed that GABARAPL1, FKBP5, and PCDH9 expression was lower in RA synovial tissues compared to healthy controls, while SLAMF8 expression was elevated. The gene discussed is PCDH9; the disease is rheumatoid arthritis.