Role of µ-Opioid Receptor Polymorphism in Patients of Rheumatoid Arthritis and their Correlation with Severity of Disease.

Introduction: With 1 billion tobacco users worldwide, nicotine dependence has a major impact on global health. Advances in medication development for nicotine dependence require an improved understanding of the neurobiology of this complex, relapsing brain disorder.

Aims: To study association of µ Opioid Receptor polymorphism in patients of rheumatoid arthritis and its correlation with severity of disease and prevalent alleles of the OPRM1 genes.

Material And Methods: This is a case control study wherein all available patients and volunteers were recruited. 142 controls subjects with no known history of disease and 85 study group cases were included.

Results: Comparison of genotype frequencies showed a statistically significant difference between the studied groups (p<0.004). A statistically significant difference was found when the allelic frequencies between the two groups were compared (p<0.0001), with the 17T allele having a-1.7518 fold higher risk of having RA (risk ratio (RR)=1.7518, 95%CI of RR=1.2988-2.3627, OR =3.2914; 95%CI =1.9608-5.5251). Significant difference was also found when the allelic frequencies between the two groups were compared (p<0.0001), with the 118G allele having a 1.5-fold higher risk of developing RA (RR)=1.5801, 95%CI =1.3091-1.9071, OR=3.1357; 95%CI 2.1083-4.6638).

Conclusion: The study definitely needs to be extended to larger cohort of patients and control samples and to a larger set of candidate µ opioid receptors. 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.