NRAMP1 polymorphism and viral factors in Sardinian multiple sclerosis patients

Abstract

Background: Multiple sclerosis (MS) is believed to be an autoimmune disease occurring in genetically predisposed individuals after an appropriate environmental exposure such as viral infections. Recent studies suggest a significant association between MS and the functional 5'-(GT)n polymorphism in the promoter region of the NRAMP1 gene. In the present study we aimed to evaluate the contribution of the allelic variation in the NRAMPI promoter to MS susceptibility and to study the role of viral infection in relation to specific NRAMP1 genotypes, in a Sardinian cohort.

Methods: Sixty MS patients and 66 healthy individuals were genotyped, and screened for the presence of Epstein-bar virus (EBV) and JC virus (JCV) sequences.

Results: Consistent with previous autoimmune disease studies, allele 3 at the functional 5'(GT)n promoter region repeat polymorphism, was significantly overrepresented among MS patients when compared to controls (p=0.02). The EBV and JCV sequences were detected in 8/60 (13.33%) and in 4/60 (6.66%) of MS patients respectively and in 5/66 (7.57%) and in 0/66 of controls.

Conclusion: The allelic variation in the NRAMP1 promoter may contribute to MS susceptibility in the Sardinian population. The viral sequences were not confined to a specific NRAMP1 genotype.