Predictive genetic testing -- new possibilities in determination of risk of complex diseases

Predictive genetic testing offers the possibility to statistically determine the risk of inheriting a complex phenotype by establishing an individual s genotype for metabolic polymorphisms. Here we discuss the conditions under which a predictive test may be offered to a patient and the problems connected with it. Examples of predictive genetic testing for multifactorial diseases and drug responses are given. We describe in detail the association of the C677T polymorphism of methylentetrahydrofolate reductase gene with hyperhomocystinemia and folate levels, as an independent risk factor for cardiovascular disease, and the association of a polymorphism of the promoter of the 5-lipoxygenase gene and the response to leukotriene inhibitors in asthma. Prospective development of genomic medicine and its use in the study of complex traits will hopefully bring significant benefit to the population and enhance the prevention and therapy of common diseases.