Impact of Single Nucleotide Polymorphism in the ANKRD55 Gene on Occurrence and Clinical Characteristics of Rheumatoid Arthritis.

Background: Rheumatoid Arthritis (RA) has multifactorial etiology and numerous genetic and environmental factors have been related to an increased risk of RA. Recently, Genome-Wide Association Studies (GWAS) suggested a large number of Single Nucleotide Polymorphisms (SNPs) loci affecting the susceptibility to RA. One of these loci is rs6859219 (C>A), a functional polymorphism in the ANKRD55 gene which was associated with the expression of ANKRD55 and IL6ST . In the current study, we evaluated the possible association between rs6859219 (intronic variant) in the ANKRD55 gene with RA risk in the Iranian population.

Methods: A case-control study using 118 RA patients and 115 healthy counterparts was undertaken in order to determine rs6859219 genotypes using real-time polymerase chain reaction High-Resolution Melting (HRM) method.

Results: There was a significant difference in the genotype and allele frequencies of rs6859219 between patients and controls (p<0.001). Logistic regression analysis demonstrates that CC genotype and C allele increased the risk of RA (OR for CC genotype = 7.12; 95%CI [3.51-15.05]/OR for C allele =4.16; 95%CI [2.78-6.28]). Furthermore, regarding the dominant and recessive model of inheritance, RA patients indicated obvious association of the rs6859219 variant compared to healthy controls (p<0.001). Moreover, in the patient group, there was a significant correlation between C-Reactive Protein (CRP) concentration with rs6859219 polymorphism (p<0.001).

Conclusion: Our findings propose a substantial correlation between rs6859219 polymorphism and RA risk and clinical characteristics of this disease in the Iranian population.