Genetic screening can be performed to learn two different results:
- To determine if an individual may have a genetic trait or disease
- To determine if an individual may carry a gene that could be passed onto their children
Although some screening tests may actually diagnose a genetic condition, other tests may only demonstrate that an individual is at higher than normal risk for having a genetic disease. In this case, the screening test needs to be followed by a diagnostic test, to determine definitively if the condition is present.
An individual may be screened for a genetic condition at birth through a process called newborn screening. A blood sample is collected from the baby’s heel and is applied directly onto a special filter card. The genetic conditions that are tested at birth vary by state. The disorders tested for 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 individuals for a genetic trait or disorder is usually considered because of a suspected predisposition or increased risk for that disorder. An individual might be considered 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 child whose brother 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 typically involves obtaining a blood sample for analysis. The serum, or liquid part of the blood, and the cells in the blood contain a large number of enzymes and other proteins which can be analyzed for signs of alteration by genetic mutation. Alternatively, DNA, which contains all the genes, can be isolated from the cells in the blood and analyzed to directly determine 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.