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Click here to go to "Ask the Geneticist", an outreach program created by Dr. Warren and the Faculty of the Department of Human Genetics to answer questions about diseases, treatments, research and predispositions to genetic disorders from the general public.
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How accurate are genetic test results?
There are a variety of types of genetic laboratory tests, but the accuracy varies depending upon the test and the type of tissue studied. Generally speaking, genetic laboratory testing is highly accurate.
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Can genetic testing tell me if I will get cancer?
There are some DNA tests available that test for the presence or absence of mutations in genes that confer an increased risk for cancer. For example, when mutated, genes such as BRCA 1 and 2 increase the risk for a person to develop breast and ovarian cancer. However, not all persons with mutations develop cancer.
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Can genetic testing predict if I will have a heart attack?
Similar to the question above, there are genetic tests that identify risk factors or mutations in genes that confer an increased risk for early-onset cardiovascular disease. However, these tests do not provide a definite answer as to if or when someone will have a heart attack.
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What types of information can genetic testing provide?
There are a variety of situations when genetic testing is done, and a wide range of information that genetic testing provides. Genetic testing is used for:
- Making a diagnosis: diagnostic testing is used to confirm or rule out a suspected genetic disorder in a patient who has symptoms.
- Predictive testing is sometimes available for persons who do not have any symptoms of a genetic disorder, but have a positive family history. There are two types of predictive testing:
Presymptomatic testing: if a gene mutation is present, the development of symptoms is certain (i.e. Huntington disease).
Predispositional testing: if a gene mutation is present, there is an increased risk to develop a disease. The mutation gives a
predisposition, but not certainty, of disease development.
- Carrier testing is used to determine whether someone carries a recessive gene that is either autosomal recessive (located on the first 22 pairs of chromosomes) or X-linked recessive (located on the X chromosome). Carriers are usually healthy and do not have any symptoms as a result of being a carrier.
It is thought that humans carry 20-50 harmful recessive genes. Carrier testing is offered when a positive family history of a recessive condition is present or in persons of various ethnic groups. Different recessive mutations have arisen over time in various parts of the world, so that certain mutations have a higher frequency in certain ethnic groups.
- Prenatal testing is offered during a pregnancy to test a fetus for a particular genetic disorder when an increased risk is identified. For example, in women 35 years of age and older, the risk for chromosome abnormalities such as Down syndrome is increased and prenatal testing is offered.
- Preimplantation testing or preimplantation genetic diagnosis (PGD) is a test conducted on an embryo after in vitro-fertilization (IVF), when there is a very high chance to have a child with a serious genetic disorder.
- Newborn Screening is a test routinely performed in the first few days of life to identify specific genetic disorders that are treatable if detected early, such as phenylketonuria (PKU) and galactosemia.
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What happens if I get results that indicate I may develop a disease?
The team of genetic experts at Emory Division of Medical Genetics will explain any genetic test results to you and your referring physician in detail, provide written information on the disease in question, discuss any preventative measures and put you in touch with other patients in the same situation. Support groups are also available for most genetic disorders.
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What if I have other questions about genetics?
Ask the Geneticist is a website service run by the Department of Human Genetics at Emory, and the Department of Genetics at the University of Alabama at Birmingham.
http://www.askthegen.org/
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