Genetic testing can provide information about a person's genes and chromosomes throughout life. Available types of testing include:
- Newborn screening
-
Newborn screening is used just after birth to identify genetic disorders that can be treated early in life. The routine testing of infants for certain disorders is the most widespread use of genetic testing—millions of babies are tested each year in the United States. All states currently test infants for phenylketonuria (a genetic disorder that causes mental retardation if left untreated) and hypothyroidism (a disorder of the thyroid gland). Some states also test for other genetic disorders.
- Diagnostic testing
-
Diagnostic testing is used to diagnose or rule out a particular genetic or chromosomal condition. It is usually offered to people who have signs of a particular disorder. This type of testing can be performed at any time during a person's life, but is not available for all genetic conditions. The results of a diagnostic test can influence a person's choices about health care and the management of symptoms.
- Carrier testing
-
Carrier testing is used to identify people who carry one copy of a gene mutation that, when present in two copies, causes a genetic disorder. This type of testing is offered to individuals who have a family history of a genetic disorder and to people in ethnic groups with an increased risk of specific genetic conditions. If both parents are tested, the test can provide information about a couple's risk of having a child with a genetic condition.
- Prenatal testing
-
Prenatal testing is used to detect changes in a fetus's genes or chromosomes before birth. This type of testing is offered to couples with an increased risk of having a baby with a genetic or chromosomal disorder. In some cases, prenatal testing can lessen a couple's uncertainty or help them make decisions about a pregnancy. It cannot identify all possible inherited disorders and birth defects, however.
- Predictive and presymptomatic testing
-
These types of testing are used to detect gene mutations associated with disorders that appear later in life. Predictive testing can identify mutations that increase a person's risk of developing disorders with a genetic basis, such as certain types of cancer. Presymptomatic testing can determine whether a person will develop a genetic disorder, such as Huntington disease (an inherited brain disorder that appears during mid-life), before any symptoms appear. The results of predictive and presymptomatic testing can help people make decisions about medical care.
- Forensic testing
-
Forensic testing uses DNA sequences to identify an individual for legal purposes. Unlike the tests described above, forensic testing is not used to detect gene mutations associated with disease. This type of testing can identify crime or catastrophe victims, rule out or implicate a crime suspect, or establish biological relationships between people (for example, paternity).
For more information about the uses of genetic testing:
Information about the types of genetic testing is available from GeneTests
. Click on “Educational Materials” at the top of the GeneTests home page and scroll down to “Uses of Genetic Testing.”
The National Newborn Screening and Genetics Resource Center offers detailed information about newborn screening.
For information about forensic DNA testing, refer to the fact sheet DNA Forensics from the U.S. Department of Energy Office of Science.
Next Topic: How is genetic testing done?
Previous Topic: What is genetic testing?
