Genetic screening may be done to find out if a person:
- Has a specific genetic trait or disorder
- Is a carrier for a gene that is linked to a genetic disorder that could be passed on to their children
Although some screening tests may diagnose a genetic condition, other tests may only show that a person is at higher than normal risk for having a genetic disorder. In this case, the screening test needs to be followed by a diagnostic test, to confirm that the condition is present.
When babies are about two days old they are screened for a number of genetic disorders through a process called newborn screening. A blood sample is collected from the baby’s heel and is applied directly to a special filter card for testing. The genetic conditions that are tested at birth vary by state. The disorders tested on the newborn screen have some form of treatment available. Babies are tested at birth for these conditions because treatment needs to be started right away to prevent the complications of the disease.
Screening can also occur later in life. Screening someone for a genetic trait or disorder may be done because of a suspected predisposition (increased risk) for that disorder. Someone may be at an increased risk for a disorder for any of the following reasons:
- Having a history of someone else in the family with a genetic disorder (e.g., a brother who died from Canavan disease)
- Belonging to a population (e.g., Ashkenazi Jews) known to be at higher risk for certain specific conditions (e.g., testing an Ashkenazi man for Gaucher disease, even when there is a non-specific problem such as fatigue or anemia)
Screening for a genetic condition often involves obtaining a blood sample for testing. The serum, or liquid part of the blood, and the cells in the blood contain a large number of products which can be tested for signs that a genetic change is present. Otherwise, DNA, which contains all the genes, can be isolated from the cells in the blood and tested to see if there is a mutation in a specific gene.
Contact your physician if you have symptoms or physical signs that you suspect may be related to a genetic disorder. Find out more about genetic testing by contacting your physician, a clinical geneticist or a genetic counselor.