Genetics of multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. Although environmental risk factors are clearly involved in MS, the importance of genetic factors has been strongly supported by the results of studies on multiplex families, though a weak association with major histocompatibility complex (MHC) has been the only genetic feature of MS consistently observed to date. Other candidates genes have been pointed out, but none has been confirmed. Recent genome scans suggest that no single MS susceptibility locus is necessary or sufficient to cause MS, and this finding is compatible with a polygenic etiology. Furthermore, MS is a heterogeneous disorder, and thus different genes may influence its course or presentation. Actually, some candidate genes have been proposed, which contribute to the genotype-phenotype interactions in MS.