Genetic screening
Genetic screening refers to two different processes: Testing individuals to see if they have a genetic trait or disease, and testing individuals to determine if they carry genes that could result in a genetic disorder in their children.
Screening (or testing) individuals for a genetic trait or disorder is usually considered because of a suspected predilection or "increased risk" for that disorder. Individuals might be considered at increased risk for any of the following reasons:
- They have symptoms or physical signs that might be caused by a genetic disorder. Example: A child with signs of neurologic degeneration might be tested for Tay-Sachs disease.
- There is a history of someone else in the family with a genetic disorder. Example: A child whose brother died from Canavan disease.
- They belong to a population (e.g., Ashkenazi Jews) known to be at higher risk for certain specific conditions. Example: Testing an Ashkenazi man for Gaucher disease, even when there is a non-specific problem such as fatigue or anemia.
Testing individuals to see if they carry, or are heterozygous for, genes that are associated with a genetic disorder may be warranted for the same kinds of reasons that sometimes warrant testing an individual to see if they have a genetic disease. These include:
- A history of someone else in the family with a genetic disorder. Example: The brothers and sisters and aunts and uncles of a child with Tay-Sachs disease.
- Membership in a population (e.g., Ashkenazi Jews) known to be at higher risk for certain specific conditions. Example: Testing all Ashkenazi Jews of reproductive age for the more common "Jewish" genetic diseases.
Testing usually 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 to see if they have been altered 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.
- If you or someone you know has symptoms or physical signs that you think might be related to a genetic disorder, contact your physician.
- If you have a relative who has a genetic disorder, you can get more information about carrier testing from your physician, a clinical geneticist, or a genetic counselor.
- If you belong to a racial or ethnic group known to be at increased risk for certain genetic disorders, you can get more information about testing from your physician, a clinical geneticist, or a genetic counselor.