Frequently Asked Questions
- Q: What is genetic testing?
- A:Genetic tests look for alterations in a person's genes or changes in the level or structure of key proteins coded for by specific genes. Genetic tests can also be used to look at levels of RNA that play a role in certain conditions. Abnormal results on these tests could mean that someone has a genetic disorder.
- Q: How do I decide whether to be tested?
- A: People have many different reasons for being tested or not being tested. For many, it is important to know whether a disease can be prevented if a gene alteration causing a disease is found. For example, those who have inherited predispositions to breast or colon cancer have options such as earlier and more frequent disease screening or early treatment. Pharmacogenetic testing can indicate the best medicine or dose of a medicine for a certain person.
- Q: What information can genetic testing give?
- A: Genetic testing can:
Give a diagnosis if someone has symptoms.
Show whether a person is a carrier for a genetic disease. Carriers have an altered gene, but will not get the disease. However, they can pass the altered gene on to their children.
Help expectant parents know whether an unborn child will have a genetic condition. This is called prenatal testing.
Screen newborn infants for abnormal or missing proteins that can cause disease. This is called newborn screening.
Show whether a person has an inherited disposition to a certain disease before symptoms start.
Determine the type or dose of a medicine that is best for a certain person. This is called pharmacogenetics.
People in families at high risk for a genetic disease have to live with uncertainty about their future and their children's future. A genetic test result that can show that a known alteration causing disease is not present in a person can provide a sense of relief.
- Q: What is a chromosomal test?
- A: Chromosomes are the large DNA-containing structures in the nucleus of a cell. Humans normally have 23 pairs of chromosomes: 22 pairs of autosomes (numbered 1 through 22) and 1 pair of sex chromosomes (either XX for females or XY for males). Chromosomal tests look at features of a person's chromosomes, including their structure, number and arrangement. These tests look for changes, such as pieces of a chromosome being deleted, expanded, or being switched to a different chromosomal location.
- Q: What is a biochemical test?
- A: Biochemical tests look at the amounts or activities of key proteins. Since genes contain the DNA code for making proteins, abnormal amounts or activities of proteins can signal genes that are not working normally. These types of tests are often used for newborn screening. For example, biochemical screening can detect infants who have metabolic conditions such as phenylketonuria (PKU). Because of a genetic defect, people with PKU lack the enzyme that breaks down a particular amino acid (protein building block) called phenylalanine. Consequently, phenylalanine builds up to higher than normal levels in the body, leading to a variety of health problems. If diagnosed early, PKU can be treated with a strict diet that is low in phenylalanine, avoiding foods that are high in protein or that contain certain artificial sweeteners