front |1 |2 |3 |4 |5 |6 |7 |8 |9 |10 |11 |12 |13 |14 |15 |16 |17 |18 |19 |20 |21 |22 |23 |24 |25 |26 |27 |28 |29 |30 |31 |32 |33 |34 |35 |36 |37 |38 |39 |40 |Glossary |review

The last decade has seen a tremendous expansion of scientific knowledge in human genetics. Our understanding of human genes and of the genetic basis of disease has grown dramatically. Currently, more than 4,000 diseases such as sickle cell anemia and cystic fibrosis are known to be genetic and are passed on in families. Moreover, it is now known that alterations in our genes play a role in such common conditions as heart disease, diabetes, and many types of cancer. The identification of disease-related genes has led to an increase in the number of available genetic tests that detect disease or an individual's risk of disease. As of this writing, gene tests are available for many disorders, including Tay-Sachs disease and cystic fibrosis. New tests are being developed to detect predispositions to Alzheimer's disease, colon cancer, breast cancer, and other conditions. As the number of available genetic tests increases, the use and interpretation of those tests and the information they generate will require a basic understanding of how genetic principles apply to different health problems such as cancer. Scientists are concerned not only that gene tests offered are reliable, but also that patients and health care professionals understand the limitations of such testing. The disclosure of test results could inflict psychological harm to a patient if safe and effective interventions are not also available. Understanding Gene Testing represents an effort by the National Cancer Institute and the National Center for Human Genome Research to provide basic information about gene testing and key genetic concepts. This booklet also provides answers to a number of frequently asked questions about the science, potential benefits, and potential risks of gene testing.