A polymorphism of the gene encoding the signaling molecule STAT4 predicts the risk of rheumatoid arthritis (RA) in patients in Spain, Sweden, and the Netherlands, researchers have confirmed.
Recent studies indicate that several polymorphisms of signal transducer and activator of transcription 4 gene (STAT4) are responsible for a strong genetic linkage between RA and a region in chromosome 2q.
Specifically, four polymorphisms in tight linkage disequilibrium form a susceptibility haplotype tagged by the T allele of one polymorphism (rs7574865), which has the most significant association with RA. This relationship has been confirmed in Korean patients and individuals of European ancestry living in the USA and Sweden.
To extend these findings to other populations, Gisela Orozco (Science Health and Technology Park, Granada, Spain) and fellow researchers used blood samples to genotype 923 RA patients from Spain, 273 patients from Sweden, and 876 patients from The Netherlands, as well as a similar number of generally healthy volunteers from those countries.
Writing in the journal Arthritis and Rheumatism, the authors report that they found a significantly increased frequency of the minor T allele of the STAT4 rs7574865 polymorphism in patients than in control volunteers.
Specifically, in Spanish patients the allele was found in 24.8% of patients and 20.8% of controls; figures that were similar in the Swedish and Dutch individuals studied.
Overall, the T allele was 1.25-times more likely in RA patients than in control volunteers, an increase in allelic incidence that was consistent with results from a meta-analysis of all published studies of the association between STAT4 and auto-immune disease.
Interestingly, however, the investigators could find no links between the presence of the rs7574865 polymorphism and major RA risk markers including rheumatoid factor and anti-cyclic citrullinated peptide.
The authors say this suggests that the polymorphism is part of a disease process separate from processes related to these factors and that it could be used to independently predict disease risk.
The authors conclude that their findings "suggest that STAT4 is a common RA susceptibility marker in European and Asian populations," but caution that their findings need replication in different cohorts to definitively establish STAT4 as an RA susceptibility marker in Asian populations.
Huh? Can someone please explain this? My husband has polymorphis light eruption as dx'd by the dermatologist. Any time he goes out in the sun he gets a nasty rash that takes weeks to heal. Several lupus tests have been negative but now I'm getting concerned. Is this a totally different kind of polymorphis?