Many people choose to undergo carrier screening before or during pregnancy, so they can learn their risk of passing on a mutated gene to their children. Labcorp offers a choice of carrier screens, from comprehensive testing for 500 disorders to targeted testing for specific conditions.
In autosomal recessive diseases, like cystic fibrosis, if both parents are carriers, each child has a 25% chance of inheriting two nonworking copies of the disease gene and being affected. Narrowing variants down to the causative one requires careful filtering based on available data.
Genetic Screening
Genetic testing looks at inherited changes (also called variants) in genes, chromosomes, and proteins. These changes can have harmful, beneficial, neutral, or uncertain effects on risk for diseases.
Some inherited gene variants are known to increase cancer risk and are included in many commercial and at-home genetic tests for hereditary cancer susceptibility syndromes. People who receive a positive result may be referred to a genetic counselor for counseling and possible referrals to other services for hereditary cancer risk assessment and care.
Whether or when to offer genetic screening for hereditary diseases is a complex decision that requires careful evaluation of the benefits, harms, and costs of such services. Despite the challenges, the number of genetic testing services continues to grow, including preconception and prenatal screening programs and population-based genetic screening for adult-onset conditions. It is important that primary care providers have a clear understanding of the current state of knowledge about these newer tests so they can discuss their use with patients.
Disease Risk Assessment
Genetic tests can help doctors determine the likelihood that a person will develop certain diseases. This information is especially useful for Mendelian disorders, where an individual’s risk is directly correlated to the presence of a disease-causing mutation.
For example, if a person’s DNA test indicates that they are a carrier of the cystic fibrosis gene mutation, then they will have a 50% chance of passing it on to their children. If those children then also carry the mutation, they will have a very high chance of developing cystic fibrosis themselves.
The test results can then be used to guide medical treatment and preventative care. For example, if a person’s mutation suggests they will develop hereditary thrombophilia, it can be used to guide the prescribing of blood thinners like aspirin or heparins. This can reduce the risk of potentially life-threatening clots and lower the risk for complications like deep vein thrombosis and pulmonary embolism. The test can also identify hereditary cancer mutations that can be used to guide personal risk-reduction strategies. These include lifestyle changes, medication, and preventive surgeries like mastectomies and lumpectomies.
Family Planning and Genetic Testing
Genetic screening can reveal mutations that can affect your chances of having a child with certain conditions, like Tay-Sachs disease or cystic fibrosis. In these cases, the father’s test results are also needed. The test is easy, using a blood sample or cheek swab. It can be done before you become pregnant, allowing you to explore your options and make informed decisions about your fertility.
It can also be used to assess your risk for certain cancers, such as inherited variants in PALB2 (breast and pancreatic cancer) or BRIP1 and RAD51C (ovarian cancer). Genetic counselors are available to review your family history and explain the results of genetic testing.
Carrier screening is often performed for couples who are trying to conceive, so they can reduce the chance of passing a disease-linked gene mutation on to their children. In these cases, the sperm or egg donor is also tested, if possible. This can help avoid conditions such as Tay-Sachs, cystic fibrosis or sickle cell anemia.
Personalized Medicine with DNA Testing
Personalized medicine can include DNA testing to identify disease-causing mutations. These tests can be used to confirm a diagnosis, determine whether a patient is a carrier of the disease, or identify if a patient has an increased risk of developing the disorder.
Many inherited heart conditions, such as arrhythmias, cardiomyopathy, familial hypercholesterolemia and coronary artery disease, have a genetic component that can increase your risk for developing the condition. Identifying these inherited mutations can help guide treatment and family planning decisions.
Some DNA tests, such as multigene panels and exome sequencing, may identify genetic variants that are not clinically actionable. These variants are sometimes referred to as incidental findings. Currently, federal law prevents health insurance companies from using DNA xet nghiem adn o ha noi test results to discriminate against people seeking coverage for life or long-term care, but these protections don’t extend to all types of insurance. The American College of Physicians has published a position paper that addresses how the ethical integration of precision medicine and genetic testing into clinical practice can be achieved.