[Genetic influences in chronic polyarthritis].

Genetically determined diseases exhibit the following characteristics: 1. They appear with different frequencies in various populations. 2. They show tendencies to aggregate in certain families. 3. The disease risk is higher for monozygotic twins than for dizygotic twins. 4. They show an association with genetically determined markers in a population e.g. certain HLA-antigens. All of these characteristics are observed in rheumatoid arthritis. Despite an abundance of data suggesting a genetic influence in the etiopathogenesis of rheumatoid arthritis, it has not been possible, as yet, to uncover a definitive genetic mechanism. There is evidence to suggest that both histocompatibility-complex-associated genetic factors and genes outside the HLA region are of significance for predisposition to the disease and possible for the pathogenesis and course of rheumatoid arthritis. Using modern genetic technology it should be possible to investigate further the influence of genetic factors on the etiology and pathogenesis of rheumatoid arthritis.