Genetic Testing
(Procedures andexaminations)
This topic will help you understand geneticDNAtesting and how to prepare for it.
What is genetic testing?
Genetic testing is a medical examination that looks for changes in your DNA—the genetic instructions of living organisms. The results can help diagnose genetic conditions, determine the risk ofdeveloping them, or identify the likelihood of passing them to future generations. The test involves analyzing genes, chromosomes, and proteins to detect changes that may cause genetic disorders.
Genetic tests assist individuals affected by or at risk of genetic conditions in making informed health decisions. These include diagnosis, screening, counseling, and support.
When is genetic testing done?
Genetic testing is conducted in various situations, such as:
If you have a family history of a genetic condition or a specific type of cancer, to determine your risk.
If you’re considering having a child, check whether you carry genes that may be passed to your offspring.
If you or your child shows symptoms that may indicate a genetic condition, for early diagnosis.
During pregnancy, prenatal testing can assess the risk ofa genetic disorder in the fetus, like Down syndrome.
For newborns, a simple blood test can screen for rare genetic conditions.
- What are the typesof genetic tests?
- There are many types of genetic tests. The appropriate one depends on symptoms, medical history, and family history. No single testcan detect all genetic disorders. A healthcare provider can guide you on the most suitable test based on your case.
- Single gene test: Focuses on changes in one specific gene. Recommended when symptoms suggest a condition usually caused by mutations in a specific gene, like Duchenne muscular dystrophy or sickle cell anemia. If a known mutation exists in the family, this test may confirm it.
- Panel testing: Examines multiple genes at once. Used when symptoms suggest a disorder potentially caused by mutations in different genes, such as primary immunodeficiencies or epilepsy. It can also screen for cancer-related genes like BRCA1/2 (breast or colon cancer risk).
- Broad geneticDNAtesting:
- Gene sequencing: Analyzes either all genes or those linked to specific conditions.
Whole genome sequencing: Analyzes the entire DNA, not just the genes. Recommended for complex medical cases or when previous tests don’t identify a genetic cause.
Clinical vs. direct-to-consumer testing:
- Clinical tests: Ordered by adoctor for specific medical reasons;DNAnot available for individual purchase.
- Direct-to-consumer tests: Purchased online or in stores, usually for ancestry or general health traits.They do not provide conclusive disease predictions and should be discussed with a doctor.
Chromosomal tests: Some tests detect chromosomal changes (structures containing DNA). For example, a chromosomal microarray test may be recommended to detect conditions such as autism.
Gene expression tests: Compare gene expression levels between healthy and diseasedcells. These can guide treatments such as chemotherapy for breast cancer.
The test type is selected based on symptoms, family history, and health status. Genetic testing aids in early detection and appropriate treatment planning, but medical consultation is essential before proceeding.
- How is genetic testing done?
- Genetic testing involves several methods of sample collection and analysis, including:
- Blood sample.
- Cheek swab or saliva using a cotton swab or small brush.
- Skin or hair sample.
Amniotic fluid sample: Collected through amniocentesis duringpregnancy to detect fetal genetic disorders.
Biopsies: In certain cases, tissue samples are collected for analysis, such as cancer-related genetic testing.
How to prepare for genetic testing?
Before testing, gather as much information as possible about your family’s medical history. Discuss your personal and family medical history with your doctor to better understand potential risks. Ask all relevant questions and express any concerns you may have. Explore your options depending on potential test outcomes.
Frequently Asked Questions:
Are genetic tests accurate?
Genetic tests are not always 100% accurate. If a test shows a genetic change, it may suggest a potential issue, but not everyone with the mutation will be affected. The impact of a genetic change varies—some may be severely affected while others are not affected at all.
Also, interpreting minor changes in genes is complex,and their health implications may be unclear.
- What do positive, negative, or inconclusive results mean?
- Positive results: A mutation was found. Depending on the test’s purpose, it may:
- Confirm a diagnosis and guide treatment planning.BRCA1/2).
Indicate that you carry a genethat could be passed to children.
Show risk for future disease (e.g., BRCA1/2 for breastcancer), though it doesn’t mean the disease is certain.
