[Principles of gene technology and potentials of DNA diagnosis]

Gene technology offers new potentialities for medicine in the diagnosis, treatment and also prevention of disease. DNA diagnostic procedures are already a cornerstone of genetic counselling. The number of mutated genes identified and, as a consequence, the number of disorders diagnosable with a molecular genetic approach, is steadily increasing. Since a given gene is present in practically all somatic cells, it can, irrespective of its expression, be analyzed using white blood cells or chorionic vili as a source of DNA. This results in an extension of disorders diagnosable before birth (prenatal diagnosis) or before its clinical manifestation (presymptomatic diagnosis) as well as in the reliable recognition of clinically healthy carriers of defective genes. DNA diagnostic procedures have already gained practical application in oncology, immunology or forensic medicine. The methodology of molecular biology allows the analysis of infectious agents in tissues or body fluids that are only present in a latent state. We are only at the dawn of the century of molecular medicine. However, our knowledge of the cause and the nature not only of rare single genetic diseases but also of common multifactorial disorders, such as cardiovascular diseases, cancer or autoimmune diseases, is increasing through gene technology. Therefore, on the one hand the new genetics holds out numerous promises and hopes, while on the other hand, a future characterized by exorbitant genetic testing increases an irrational fear of this technology in the public. Members of the medical profession must interest themselves in molecular genetics in order to be able to follow the development of modern medicine but also to inform their patients and the general public about the new possibilities and limitations, as well as any risks, of genetic testing. This is the only way to ensure proper use of gene technology in medicine without irrational legal restrictions imposed by an ill informed public.