Q222R polymorphism in the DNAse I gene is not associated with susceptibility to rheumatoid arthritis or to disease course in an Argentine patient cohort

BackgroundNeutrophils are able to trap and kill microbes via the release of their DNA decorated with proteins from granule and histones into the extracellular environment; however, this mechanism has also emerged as a potential source of auto-antigens and inflammation during the course of many autoimmune diseases. It has been demonstrated that neutrophils from patients with rheumatoid arthritis (RA) have a greater propensity to release neutrophil extracellular traps (NETs). DNAse I, an endonuclease involved in the breakdown of chromatin, has been implicated in the pathophysiology of autoimmune diseases.Aim of the workTo investigate the genetic associations of a non-synonymous single nucleotide polymorphism (SNP) in DNAse I with the risk of RA and its influence on clinical and radiographic features in an Argentinean population.Patients and methodsThe Q222R A/G DNAse I SNP was studied in 210 RA patients and 206 matched healthy controls. Disease activity score, health assessment questionnaire and the modified Sharp van der Heijde score were assessed.ResultsThe patients' median age was 56 years (48-64), disease duration 128 months (20-205) and 86.7% were females. Genotype distribution and G-allele frequency were comparable between patients and control. There was no significant association of the Q222R A/G genotypes with disease susceptibility, activity, functional status or radiological score among RA Argentine patients.ConclusionsNo significant genetic association was found between the carriage of the DNAse I Q222R G-allele and the risk of RA nor was there any association with the disease activity, functional capacity or severity in an Argentine patient cohort.