Neuromyelitis Optica (NMO IgG+) and Genetic Susceptibility, Potential Ethnic Influences.

Abstract Neuromyelitis optica (NMO) and multiple sclerosis (MS) have been reported in different populations. NMO is more frequent in non-Caucasians, and clinical phenotype differences between populations are likely influenced by genetic susceptibility. In Brazil, it has been reported that NMO patients have a mainly European ancestry background. Like other autoimmune diseases, NMO has a multifactorial origin (i.e., genetics, environmental and infectious factors). Regarding the genetics of NMO, epidemiological findings suggest that a polygenic background has an important role in the development of this type of disease. In this context, various genes have been studied, such as those involved in the synthesis of the T cell beta chain receptor, the VH2-5 gene, myelin basic protein, the CTLA-4 gene, and the interleukin-1 gene. We performed a study with the main objective of identifying candidate genes involved in the susceptibility to develop NMO in a Mexican population. We included 35 patients with an NMO diagnosis according to the Wingerchuk 2006 criteria. The mean age of the patients was 43.3 years old (20-67), and 80 percent of the patients were women. The presence of HLA-DRB1*03 and HLA-DRB1*10 alleles were more frequent in NMO patients than in controls (n=198; p=0.03 and 0.005, respectively). There were no differences in the other alleles that have been described in MS subjects, such as HLA-DRB1*04, HLA-DRB1*08 and HLA-DRB1*13. These findings may support the hypothesis that implicated immune-genetics as a key factor in development of this type of disease.