Association of CRP Haplotypes in Rheumatoid Arthritis and their Correlation with Severity of the Disease

Rheumatoid arthritis is a heterogenous autoimmune disorder of unknown cause with variable clinical expression. Genetic factors play an important role and likely account for about 60% of disease susceptibility and expression. The aim of this study to find out the association of CRP haplotypes in rheumatoid arthritis and their correlation with severity of the disease.

This was case control study where in all available patients and volunteers (only for blood samples) were recruited. Peripheral blood samples of patients were collected at Rheumatology Clinic and Medicine Department of S.P. Medical College, Bikaner in collaboration with Department of Biological Sciences, BITS, Pilani-Hyderabad during July 2009 to January 2012. 100 control subjects with no known history of disease and 135 cases were recruited as per pre-decided inclusion and exclusion criteria. A tag SNP approach captured common variation at the CRP locus and the relationship between genotype and serum CRP was explored by linear modelling.

Cases comprised of 98 females (Mean age 43.01+13.23 yrs) and 37 (mean age 47.4+14.9 years) males. The Control group comprised of 100 unrelated healthy controls. The cases and controls did not differ significantly for any of the clinical parameters, except for serum CRP levels. The allele distribution of rs1205 polymorphism among the studied cases and controls, which was statistical non-significant. The rs3093066 polymorphism located at the 3` position of the gene in the UTR at position number 157949723. The rs3116640 polymorphism located at 157948938 position on chromosome1 and the allele distribution of rs3116637 polymorphism among cases and controls which was also found to be monomorphic respectively.

Extending the studies to a larger cohort will also allow genetic analyses of clinically defined endophenotypes observed in the patients of this chronic metabolic disease with attributes of autoimmune disorder and multiple symptoms in patients. Genetic studies can also impact strategies adopted for effective personalized treatment for this progressively debilitating disease.