Multiple sclerosis: multiple etiologies, multiple genes?

Multiple sclerosis is a chronic inflammatory disease characterized by multifocal damage of the central nervous system myelin. Both humoral and cell-mediated immune abnormalities have been observed in patients with multiple sclerosis, but their relation to the demyelination process is not understood. The etiology of the disease is still unknown; however, evidence exists for an interplay between environmental and genetic factors. Several genes are involved in determining the disease susceptibility, at least one of them encoded within human leukocyte antigen gene complex. Other genomic regions coding for components of the immune system or myelin have also been suggested. Clinical, immunological and genetic data suggest that multiple sclerosis may turn out to be a heterogeneous disease. Therefore, molecular genetic dissection of this complex disease should provide important clues to its pathogenesis as well as unravel metabolic pathways for potential therapeutic or preventive strategies. This review will give an overview of recent progress and future challenges in identifying susceptibility genes for multiple sclerosis.