The gene encoding signal transducer and activator of transcription 4 (STAT4) has been reported to be associated with rheumatoid arthritis (RA) in several populations. This work aimed at assessing the association of STAT4 G>T gene polymorphism with the susceptibility, activity and functional disability of RA in Egyptian subjects.
This study included 112 unrelated RA Egyptian patients who were compared to 122 healthy unrelated individuals taken from the same locality. For all subjects, DNA was genotyped for STAT4 G>T (rs7574865) polymorphism using the PCR-RFLP technique. Antibodies to cyclic citrullinated peptides (anti-CCP) were measured by enzyme-linked immunosorbent assay (ELISA).
Cases showed a significantly higher frequency of the STAT4 T allele carriage (GT+TT genotypes) compared to controls (51.8% vs. 31.1%, OR = 2.37, 95% CI = 1.39-4.05, p = 0.001). Also the frequency of the STAT4 T allele was significantly higher among cases compared to controls (30.4% vs. 16.8%, OR = 2.16, 95% CI = 1.39-3.35, p = 0.001). Cases positive to the STAT4 T allele (GT+TT genotypes) showed no significant difference compared to those with the GG genotype regarding their clinical and immune parameters. Nonetheless, they showed a more functional disability presented in their significantly higher health assessment questionnaire (HAQ) score (p = 0.02).
This study gives an extra evidence to the association of the STAT4 T allele with the susceptibility and functional disability of RA.