Lack of association between STAT4 rs7574865 polymorphism and autoimmune diseases including rheumatoid arthritis and systemic sclerosis in Southwest Iran

- Analyzing the association between rs7574865 G/T STAT4 SNP and RA/SSc in Iran.
- Rs7574865 G/T STAT4 SNP is not associated with RA in Khuzestan population.
- Rs7574865 G/T STAT4 SNP is not associated with a susceptibility to SSc in Khuzestan population.

Systemic sclerosis (SSc) and Rheumatoid arthritis (RA) are types of autoimmune diseases. Susceptibility to these diseases depends on a complex interaction between environment and genetic factors. It is likely that common underlying genes are involved in mentioned diseases. In recent years, researchers focused on the genes encoding immune regulatory proteins, such as the STAT4 that encodes a transcription factor and plays a key role in the signaling pathways of IL-12, IL-23 and type 1 interferon. Several reports have demonstrated that these pathways are involved in RA and SSc pathogenesis. Single nucleotide polymorphism (SNP) “rs7574865 G > T” in the STAT4 gene, has been reported to be associated with RA and SSc in many ethnic groups. The aim of the present study was to investigate the association of rs7574865 polymorphism in STAT4 gene with RA and SSc diseases in Khuzestan province of Iran. The study included 320 persons (120 patients with RA and 80 patients with SSc and 120 matched healthy controls). Genomic DNA was isolated and genotyped using Restriction Fragment Length Polymorphism-polymerase chain reaction (PCR-RFLP) assay for the STAT4 gene rs7574865 polymorphism. The statistical analyses were performed by SPSS software. No significant association was observed between STAT4 rs7574865 polymorphism and RA (P value = 0.916) as well as SSc (P value = 0.344) in the Khuzestan province population. The correlation was examined between the clinical characteristics (RF and anti-CCP) and genotype frequencies. No evidence was found between anti-CCP and STAT4 rs7574865 genotypes. However, our result showed significant association between STAT4 rs7574865 genotypes and RF in this population (p = 0.01). Our findings suggest that there is no association between STAT4 rs7574865 polymorphism with susceptibility to RA and SSc in Khuzestan province.