Retrogen is pleased to offer diagnostic testing for genetic diseases. Tests include complete gene analysis by Sanger DNA sequencing, the gold standard for genetic testing. All tests must be ordered through a health care provider such as your physician or genetic counselor.
What is Genetic Testing?
Genetic testing involves examining a person’s DNA for changes or alterations in their genes that may lead to a genetic disorder; such changes are called genetic variants or mutations. Test results can confirm or rule out a suspected genetic condition, and help determine a person’s chance of developing or transmitting a genetic disorder.
Although genetic testing can provide important information for diagnosing, treating and preventing illness, there are limitations. Results depend both on reliable laboratory procedures and appropriate interpretation of results. Interpretation of test results is often complex even for geneticists, physicians and other health care specialists. For example, if you’re a healthy person, a positive result doesn’t always mean you will develop disease. Alternatively, a negative result doesn’t insure you won’t have a certain disorder. In some cases, a genetic test may not provide useful information. Everyone has genetic variation and often this variation doesn’t impact health. But, it may be difficult to distinguish between disease-causing and harmless variation. In these situations, follow-up testing may be recommended. Further, genetic testing only targets a specific gene or small set of genes. Disease causing variation may exist in genes that are not examined in any particular patient. Special training is required to convey information about genetic tests to affected individuals and families. A genetic counselor can provide information about the pros and cons of the test, and discuss the social and emotional aspects of testing. Before undergoing genetic testing, it may be helpful to discuss your personal and family medical history with your doctor or genetic counselor. If being tested for a genetic disorder that runs in families, you may want to discuss your decision to undergo genetic testing with your family. Having these conversations before testing will provide a feeling for how your family might respond to the test results and how it may affect them.
Research studies are constantly identifying new associations between specific gene mutations and disease, and this number will increase as DNA sequencing and other technology improves. Over 1,000 tests are now available to help determine whether a person carries a particular disease-associated mutation.
Types of Genetic Tests
Prenatal testing detects abnormalities in a fetus’s genetic complement. These tests are carried out during pregnancy when there is increased risk that a baby will have a genetic disorder. Test results can assist couples make decisions about pregnancy. Down Syndrome is one of the most common genetic diseases screened by this method.
Newborn screening is the most common type of genetic testing. Tests to identify genetic disorders in babies are done as preventative health measures, since results can often dictate successful treatment options. For example, if results show a disorder such as congenital hypothyroidism or phenylketonuria (PKU), care and treatment can begin immediately.
Diagnostic testing is used to identify, or rule out, a specific genetic condition in patients that present defined clinical symptoms. Testing can be performed before birth or at any time thereafter. Test results can influence a person’s choices about future health care and life style decisions.
A carrier test is undertaken for a condition where the patient is well, and will never develop the disorder themselves, but may transmit the disorder to their children. This type of test is recommended for individuals with a family history of a particular genetic condition. If both parents are tested, the results can provide information about a couple’s risk of having an affected child. Examples include cystic fibrosis and fragile X syndrome.
A predictive test is undertaken for a patient who is well, but has a family history of a particular disorder. Tests can identify mutations that increase a person’s risk of developing disorders with a genetic basis such as Huntington’s disease and cancer susceptibility. Results of predictive testing can help patients make decisions about medical care.
Paternity testing uses DNA sequences to establish biological relationships between people. Unlike the other tests described above, paternity testing is not used to detect genetic abnormalities associated with disease.