Predictive medicine: recombinant DNA technology and adult-onset genetic disorders.

Genetic factors are of great importance in common adult-onset disorders such as atherosclerosis, cancer, and neuro-degenerative diseases. Advances in DNA technology now allow identification of persons at high-risk of developing some of these diseases. This advance is leading to predictive medicine. In some genetic disorders, such as those leading to atherosclerosis and cancer, identification of high-risk individuals allows intervention which alters the natural history of the disorder. In other diseases, for which there is no treatment, such as Huntington's disease, the application of this technology provides information that relieves uncertainty and may affect quality of life, but does not alter the course of the illness. General implementation of predictive testing programs awaits the results of pilot projects, which will demonstrate the needs, appropriate levels of support, and guidelines for delivery of such testing.