Quantifying environmental risk factors for multiple sclerosis in discordant monozygotic twins: A case report

Abstract

Relative contribution of genetic and environmental risk factors in complex disorders is widely explored through discordant identical twins. Multiple sclerosis is a demyelinating disease of the central nervous system in which the interplay of genetic and environmental risk factors define the disease pathogenicity. Robust epidemiological studies in different populations suggested that active levels of serum vitamin D and viral load implicate in MS pathogenicity and severity. In order to refine non-shared components of susceptibility factors in MS, we investigated the role of serum 25-hydroxyvitamin D and viral infection in a pair of identical twins remained discordant for MS during the course of 5 years follow up. Here we report serological finding regarding the viral load and serum 25-hydroxyvitamin D level in a pair of discordant monozygotic twins. Based on our observation, lower levels of serum 25-hydroxyvitamin D and higher anti-viral IgG titre was consistent with the disease statues in the affected sib. collectively contribute to the pathogenesis of the disease. In order to control for genetic risk factors and uniquely examine the role of vitamin D and infectious agents on the onset of disease we investigated the status of serum 25-hydroxyvitamin D (25-OH-D) and antibody titres against EBV, CMV and HHV-6 in a pair of discordant monozygotic twins. Keywords METHODA pair of discordant MZ twins were recruited from our registry of MS patients at the Kashani Hospital. The family pedigree and clinical features of the sib are provided in the Figure 1 and Table 1. For the affected individual McDonald's criteria of MS diagnosis was carefully fulfilled. Absence of MS complications in the health sib was also investigated through clinical evaluation and confirmed by MRI and immunologic assay. The subjects were fully informed about the study procedure and written consent was obtained.