Genetic Polymorphisms of miR-146a and miR-155 in Psoriasis and Psoriatic Arthritis: Evidence from a Turkish Case-Control Study

Introduction: Psoriasis, a widespread inflammatory cutaneous disease, is driven by an interplay of genetic and environmental risk factors. miR-155 and miR-146a have been implicated in the regulation of inflammatory pathways. Objectives: In the current study, we examined the association between miR-155 rs767649 and miR-146a rs2910164 variants and the predisposition to psoriasis and psoriatic arthritis. Methods: A total of 544 individuals, including 284 psoriasis cases (68 with psoriatic arthritis) and 260 controls, were enrolled in the present study. Real-time polymerase chain reaction (qPCR) method was used to detect the genotypes of study groups. Results: The frequencies of the rs2910164 C allele, CC, and GC genotypes were significantly higher in the patient group (P<0.001), while the frequencies of the rs767649 A allele and AA genotype were higher in the control group (P=0.005 and P=0.002, respectively). No statistically significant difference in genotype or allele frequency was observed between patients with and without psoriatic arthritis (P>0.05). Rs2910164 CC and GC genotypes were found to be associated with a younger age at disease onset (P=0.006), and CC genotype was associated with higher PASI score (P=0.024). Conclusion: The present data suggest an association between the presence of the miR-155 rs767649 and miR-146a rs2910164 variants and susceptibility to psoriasis in the Turkish population. However, although the number of patients with psoriatic arthritis in our study was relatively small, no association was found between these variants and the development of psoriatic arthritis. Furthermore, the rs2910164 polymorphism was found to be associated with both early-onset disease and PASI score.