A common misconception in the medical community is that genetic disorders consist of a collection of extremely rare conditions not often relevant to day-to-day clinical practice. In fact, essentially every medical condition affecting mankind has at least some genetic component to its etiology. The study of how mutations in single genes cause rare disease (genetics) is gradually being eclipsed by research on how mutations in multiple genes interact with each other and the environment to result in health and disease (genomics). Knowledge derived from genomic discoveries is reshaping the underpinnings of much of medical practice, and will continue to do so for decades to come. At a practical level, recent advances have taught us a tremendous amount about the basis of common conditions like diabetes, heart disease, and cancer. This new knowledge is being rapidly translated into approaches for disease risk assessment, prevention, and treatment. Likewise, the study of how genes affect drug metabolism (pharmacogenetics) is being increasingly used to inform drug prescribing (see Chapter 48). Importantly, primary care physicians should not lose sight of the fact that so-called rare single-gene disorders collectively comprise a significant proportion of pediatric and adult illnesses.
Primary care physicians are in a unique position to diagnose genetic disorders because they are often the first contact for patients and also provide care for multiple family members. Recognition of, and subsequent attention to, the presence of genetic risk factors for disease in an individual can be lifesaving for the individual and their relatives. Further, as pharmacogenetics becomes increasingly important to drug therapy, primary care providers will need to be aware of and comfortable with ordering and interpreting this type of testing prior to prescribing a variety of medications.
The recent advent of new "direct-to-consumer" (DTC) genetic tests purporting to inform consumers on genetic aspects of everything from their ear-wax type to their risk of developing serious medical conditions has garnered significant media attention and public interest. Many in the scientific community feel that tests such as "genome-wide scans" are being prematurely made available for clinical use outside of carefully controlled research environments. The DTC movement will place additional responsibility on primary care providers to become literate in genomics in order to responsibly guide patients seeking advice regarding such tests.
Feero W et al: Genomic Medicine—An Updated Primer. NEJM 2010; 362:2001-2011.
Hunter D et al: Letting the Genome out of the Bottle—Will We Get Our Wish? N Engl J Med 2008; 358: 105.
Collecting family history information and recognizing key symptoms and signs are the most important components in identifying genetically influenced disorders.
Most common diseases result from a combination of exposure to environmental factors and the effects of variations in multiple genes. Inherited variations confer individual risks that can be distinguishable from the population-based average, and hundreds of such variations have ...