Maryam Sadat Seyedsadr - Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
Sepideh Dashti - Department of Human Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Multiple sclerosis (MS) is an autoimmune and neurodegenerativedisease of central nervous system (CNS)which is affecting more than ۲ million individuals in theworld. During the acute phase of the disease, neuroinflammation,the activation and invasion of immune cellsto CNS and demyelination are prominent. However, inthe chronic and progressive phase of the disease, the immunologicalaspects decline and demyelination and axonaldegeneration leads to permanent disability of patients.Since introduced at ۱۸۶۸, the etiology of MS remainsunclear. Two general hypotheses try to explain theetiology: outside-in and inside-out. The former which ismoreaccepted, indicated that the disease starts with a malfunctionin specific types of immune cells (outside of CNS)which can be explained by genetic factors. In the latter hypothesis,a signal from CNS -like exposure to myelin antigensor similar antigens from viruses/bacteria- elicit theharsh immune response. There are some evidences foreach one but at present the most accepted opinion is toconsider MS a heterogeneous disease in which genetic predispositionandmanyenvironmental factors are evaluatedin the disease onset (۱, ۲).

Common Genetic Variants, HLA-DRB۱, Sphingosine-۱-Phosphate Receptor-۲, Familial Risk, Multiple SclerosisSusceptibility