en Cellular and molecular Neuroscience Cellular and molecular Neuroscience Original Original <p dir="ltr" style="text-align: justify;"><strong>Introduction:</strong> Multiple Sclerosis (MS) is a disease of central nervous system that mainly causes lesions or plaques in the spinal cord and brain. The purpose of this study was to analyze the relation between c.-813C>T (rs2070744) and c.894G>T (rs1799983) polymorphisms of NOS3 gene and MS in Iranian patients.<br> <strong>Methods:</strong> A total of 78 patients with MS and 80 healthy controls were screened for NOS3 (rs2070744 and rs1799983) Single Nucleotide Polymorphisms (SNPs) by tetra-primer multiplex ARMS-PCR and PCR-RFLP.<br> <strong>Results:</strong> Genotype frequencies of the c.-813C>T polymorphism in patients compared to controls were as follows: 53.8% to 80.0% for TT genotype, 41.0% to 18.8% for TC genotype, and 5.1% versus 1.2% for CC genotype (P=0.001). The frequencies of GG genotype was 57.7% and 78.8% and for GT genotype of c.894G>T polymorphism in patients compared to control subjects was 42.3% and 21.2%, respectively (P=0.004).<br> <strong>Conclusion:</strong> Our results indicate that the studied NOS3 polymorphisms may be associated with MS in Iranian patients.</p> Multiple sclerosis, NOS3 gene, rs2070744, rs1799983, Polymorphism 279 284 http://bcn.iums.ac.ir/browse.php?a_code=A-10-810-1&slc_lang=en&sid=1 Mohammad Mehdi Heidari Heidarimm@yazd.ac.ir 13700319475328460010876 13700319475328460010876 Yes Department of Biology, Faculty of Science, Yazd University, Yazd, Iran. Mehri Khatami m.khatami@yazd.ac.ir 13700319475328460010877 13700319475328460010877 No Department of Biology, Faculty of Science, Yazd University, Yazd, Iran. Yaser Tahamtan Tahamtan.Yaser@yahoo.com 13700319475328460010878 13700319475328460010878 No Department of Biology, Ashkezar Branch, Islamic Azad University, Yazd, Iran.