Genetic risk factors in multiple sclerosis and approaches to their identification

Development of multiple sclerosis (MS) is believed to involve genetic as we ll as environmental factors. A complicating aspect to the study of aetiolog ical factors in MS concerns the possible existence of genetically different subtypes of the disease. In addition, a relatively large number of suscept ibility genes could be involved. Most likely, the contribution of the singl e genes to the susceptibility to MS is modest. However, interactions betwee n different genes could result in a dramatic increase in disease susceptibi lity (synergistic gene effects). In this short review we focus upon genetic heterogeneity and gene interactions in MS. We also outline approaches to t he genetic analysis of complex disease traits such as MS.