Question

What is genetic testing?

Answer 1

Genetic testing examines a person’s DNA, chromosomes, or proteins to look for changes (variants) that can cause or increase the risk of disease, affect drug response, or inform family planning and ancestry.

What it can be used for
- Diagnostic: find the cause of symptoms or a suspected genetic disorder.
- Predictive/risk: estimate future risk for conditions (e.g., BRCA1/2 for breast/ovarian cancer).
- Carrier screening: determine if someone carries a change that could be passed to children.
- Prenatal and newborn screening: detect genetic conditions before or just after birth (including noninvasive prenatal testing, NIPT).
- Pharmacogenomic testing: predict how someone will respond to certain medications.
- Forensic and ancestry testing: identification and family history information.

How it’s done (types and samples)
- Sample: usually blood, saliva, or cheek swab; prenatal tests may use maternal blood, amniotic fluid, or chorionic villus sampling.
- Methods: single-gene tests, targeted mutation panels, multi-gene panels, chromosomal tests (karyotype, chromosomal microarray), exome sequencing, whole-genome sequencing, and specific assays for repeat expansions or methylation.

Interpreting results
- Results are typically reported as pathogenic/likely pathogenic (disease-causing), benign/likely benign, or variant of uncertain significance (VUS).
- A VUS does not mean disease; it may need re-evaluation as new evidence emerges.
- Some findings affect medical management; others may be mainly informative for family planning.

Benefits and limitations
- Benefits: can clarify diagnosis, guide treatment/prevention, inform relatives’ risks, and enable informed reproductive choices.
- Limitations: not all conditions are detectable; tests can yield uncertain results or false positives/negatives; interpretation can be complex.
- There are potential psychosocial, financial, and privacy implications.

Practical considerations
- Genetic counseling is recommended before and after testing to discuss benefits, limitations, and implications for you and your family.
- Ask about test sensitivity, what exactly will be analyzed, possible outcomes, cost, turnaround time, and data privacy protections.
- In the U.S., the Genetic Information Nondiscrimination Act (GINA) protects against health-insurance and employment discrimination based on genetic information, but it does not cover life, disability, or long-term care insurance.

If you want, tell me why you’re asking (family history, pregnancy, medication concerns) and I can explain which type of testing might be relevant and what to expect.