RAR-related orphan receptor A (RORA): A new susceptibility gene for multiple sclerosis

Retinoic acid receptor-related orphan receptor alpha (RORA) is proposed to promote Th17 cells differentiation that play a crucial role in many inflammatory diseases, including multiple sclerosis (MS). The gene is also involved in regulation of inflammatory responses and neuronal cell development. The aim of the present study is to determine if any relation exists between RORA rs11639084 and rs4774388 gene polymorphisms on the individual susceptibility of multiple sclerosis. 410 patients with clinically definite MS and 500 ethnically-matched healthy controls participated in this study. Genotyping was performed using tetra primer-amplification refractory mutation system-PCR (4P-ARMS-PCR) method for the mentioned polymorphisms in the RORA gene. Both variants showed significant differences in allele and genotype distributions between the studied groups. Genotypes were risk associated in additive (P-value of 0.0003 and odds ratio equal to 1.7 (95% CI: 1.27-2.26)), dominant (P-value of <0.0001 and odds ratio equal to 0.55 (95% CI: 0.41-0.73)) and recessive (P-value of 0.04 and odds ratio equal to 0.33 (95% CI: (0.12-0.96)) models for rs11639084. However, the rs4774388 genotypes were risk associated in recessive model with a P-value of 0.036 and an odds ratio of 0.62 (95% CI: (0.4-0.97)). To the best of our knowledge this is the first report concerning the association between RORΑ gene polymorphisms and MS. The further study of RORΑ related pathways and gene networks might result in the better understanding of the pathophysiology of MS and related symptoms.