The Future of DNA Diagnostics

Over the next several years, DNA diagnostics will become more prominent in the management of patient care, and, more importantly, in the practice of predictive and preventive medicine. Four topics will be discussed: (1) What has been learned thus far from experience in DNA diagnostics? (2) What are the forces that will change DNA diagnostics in the future? (3) What kinds of genes will be important in future DNA diagnostic tests? and (4) What is the future of DNA testing? While some of the examples are drawn from BRCA testing, it should be strongly emphasized that the field of DNA diagnostics is much broader than any one area, and that numerous academic and industry groups are working to build the future for DNA diagnostics. While DNA-based tests for a variety of conditions have been available for some time, the discovery of BRCA1 marked a milestone in that it was the first highly penetrant gene discovered in a disease that affects many individuals. As a result, global awareness grew rapidly of the potential of DNA diagnostics to alter medical practice. The potential changes, sweeping as they may be, provoked reactions among health care professionals and the public. For the first time, there was an important gene that could be targeted to cure disease in patients or even prevent disease in individuals not yet affected. Biomedical researchers began studying the biology of BRCA1 to take advantage of the new information in the treatment and understanding of disease. Because deleterious mutations in BRCA1 were discovered to place a large number of mutation carriers at a very high risk of breast and ovarian cancer, professional organizations developed guidelines regarding genetic testing, placing emphasis on identifying individuals truly at risk and advising individuals through genetic counseling about the benefits and limitations of the new information. Concerns about the misuse of genetic information about an individual prompted the passage of federal legislation in the United States, both in the areas of health insurance (Health Insurance Portability and Accountability Act (HIPAA)) and employment law (the American Disabilities Act (ADA)). Through contractual and other additional means, the individual’s rights to confidentiality and nondiscrimination are further protected. To date, no case of genetic discrimination from BRCA testing has been reported. As BRCA testing marks a change, it is indicative of why DNA testing will become more widespread. The power of genetic testing is the ability to transform familial risk into individual risk, where specific actions can be targeted to benefit individuals that carry clinically important mutations. Acceptance of susceptibility testing for breast and ovarian cancer is growing worldwide as a way to determine the individual risk and to design surveillance and therapies that will benefit these individuals. For inherited disorders, germline mutations offer the best way to assess predisposition. The penetrance of the condition is very important in predicting the risks for mutation carriers. In some disorders, the distribution of mutations is simple, while for others it can be quite complex (such is the case for BRCA mutations). In some cases, the gene discovered will merely be “associated” with the condition, while in others it will be causal. Indeed there is also much work to be done in non-inherited, environmental and Short Communication