HLA Allele Frequencies in Iranian Optiocospinal Multiple Sclerosis Patients:--Hla in Opticospinal Ms (Report‪)‬

1. INTRODUCTION The etiology of multiple sclerosis (MS) is unknown, and pathogenesis of the disease encompasses multiple inflammatory as well as apoptotic process in the central nervous system [1-3]. Epidemiological studies indicate both genetic and environmental component in MS susceptibility [4]. The human leucocyte antigen (HLA) system provides a set of genetic loci which lend themselves to systematic study. In fact both linkage and whole genome association screens revealed a prominent role for alleles of the major histocompatibility complex class II gene HLA-DRB1 [5]. Of interest, in northern European-descended populations, association with this gene was identified only within families that carried the HLA DRB1*1501 allele [6]. This observation demonstrates that only a portion of familial MS is associated with allelic variation in this gene. Therefore other genes must contribute prominently to MS susceptibility of DRB1. The fact that familial MS has at least 2 forms, the variety associated with HLA-DRB1 and the form without this association, onclusively demonstrates that MS is immunogenetically heterogenesis.