Genetische Polymorphismen und Prädisposition

Genetic polymorphisms are genetic variants with a population frequency for the rare variant of at least one percent. These genetic variants may contribute directly to the pathogenesis of the disorder or may act as a marker. Polymorphisms may therefore play a direct or indirect role for many disorders. A typical example may be the congenital deficiency of mannose-binding lectin (MBL). MBL is essential for opsonisation of capsid carrying bacteria and yeast and plays an important role for infantile immunity. About 5-10% of the Austrian population carry polymorphisms in the MBL-2 gene that lead to a measurable MBL deficiency. This deficiency leads to increased susceptibility of meningococcal and pneumococcal infection mainly during early infancy. The reliable analysis of polymorphisms using molecular genetic techniques allows estimation of disease risk and sometimes initiation of preventive measures. In case of MBL deficiency vaccination will prevent meningococcal and pneumococcal disease.