What is Genetic Testing?
Genetic testing identifies changes in genes, chromosomes, or proteins to confirm a suspected condition or assess the risk of developing or passing on a genetic disorder.
Overview
Genetic testing is a type of medical test that identifies changes in genes, chromosomes, or proteins. The results can confirm or rule out a suspected genetic condition or help determine a person’s chance of developing or passing on a genetic disorder. More than 77,000 genetic tests are currently in use, and others are being developed.
What Genetic Testing Looks For
- Genes: Gene tests study DNA sequences to identify variations (mutations) that can cause or increase the risk of a genetic disorder. Tests may be narrow or broad, analyzing a single nucleotide, one or more genes, or the entire genome.
- Chromosomes: Chromosomal tests analyze whole chromosomes or long DNA segments to detect large genetic changes, such as an extra copy of a chromosome, that cause a condition.
- Proteins: Biochemical tests examine the amount or activity level of proteins or enzymes; abnormalities can indicate DNA changes that result in a genetic disorder.
Decision to Test
Genetic testing is voluntary. Because testing has benefits as well as limitations and risks, the decision to be tested is personal and complex. A geneticist or genetic counselor can provide information about the pros and cons and discuss the social and emotional aspects of testing.
Resources for General Information
- MedlinePlus offers a list of links to information about genetic testing.
- The Genetic Testing Registry, a service from the National Library of Medicine, provides a searchable database of genetic tests.
- The National Human Genome Research Institute provides an overview of this topic in its Frequently Asked Questions About Genetic Testing.
Related Topics in the Genetic Testing Chapter
- What is genetic testing?
- What are the different types of genetic tests?
- What are the uses of genetic testing?
- How is genetic testing done?
- What is informed consent?
- How can I be sure a genetic test is valid and useful?
- What do the results of genetic tests mean?
- What is the cost of genetic testing, and how long does it take to get the results?
- Will health insurance cover the costs of genetic testing?
- What are the benefits of genetic testing?
- What are the risks and limitations of genetic testing?
- What is genetic discrimination?
- Can genes be patented?
- How are genetic screening tests different from genetic diagnostic tests?
- How does genetic testing in a research setting differ from clinical genetic testing?
- What are whole exome sequencing and whole genome sequencing?
- What are secondary findings from genetic testing?
- What is noninvasive prenatal testing (NIPT) and what disorders can it screen for?
- What is circulating tumor DNA and how is it used to diagnose and manage cancer?