Immunologie in de medische praktijk. XXVI. Immunogenetica van chronische inflammatoire darmziekten

- Epidemiological and family studies have shown that the inflammatory bowel diseases (IBD), encompassing ulcerative colitis and Crohn's disease, are in large part genetically determined.

- This genetic susceptibility is complex and does not follow Mendelian inheritance patterns. The search for susceptibility genes is further complicated by genetic and clinical heterogeneity.

- Recent developments in molecular biology have enabled the identification of chromosomal regions and genes underlying IBD.

- Genetic association studies have established a role of HLA genes and cytokine gene polymorphisms in the pathogenesis of IBD.

- Whole genome linkage analysis studies using microsatellite markers and affected sib-pair analysis have identified two chromosomal locations (IBD1 on chromosome 16 and IBD2 on chromosome 12) associated with IBD.

- Recent investigations have shown that some chromosomal regions play a role in several autoimmune disorders. This suggests the presence of two types of genes in these diseases: genes that encode proteins that play a key role in the immune response and predisposing for autoimmune diseases in general, and disease-specific genes that are responsible for the phenotype and the severity of the disease.