On the genetic contribution to selected multifactorial diseases with autoimmune characteristics

The genetics of multifactorial diseases characterized by autoimmune phenomena are elusive so far. Yet, it is clear that the genetic contribution to a given clinically defined autoimmune disease entity is mostly variable and highly complex. On the basis of two basically different model diseases, Wegener's Granulomatosis and multiple sclerosis, approaches are discussed to unravel at least certain genetic predisposition factors. Major difficulties in these analyses arise from (in)exact definition of the clinical phenotype (disease entity), the vast number of potential candidate genes, the small to modest contribution of each genetic variation to disease risk and the combinatorial possibilities.