A gene test is a medical examination that identifies variations in a person’s chromosomes, genes, or proteins. These laboratory methods analyze an individual’s DNA to uncover changes that provide information about their unique genetic makeup. Understanding these genetic differences can reveal insights into a person’s health profile or their likelihood of developing certain conditions, helping to confirm or rule out suspected genetic conditions and inform future health management.
Purposes of Genetic Testing
Genetic testing serves various purposes. Diagnostic testing identifies or excludes a particular genetic or chromosomal condition when symptoms suggest a possible genetic cause. This testing can be performed at any point in a person’s life, helping to confirm a diagnosis and guide medical care.
Predictive and presymptomatic testing finds gene changes that increase the chance of developing a disease later, often before symptoms appear. This is relevant for conditions with a family history, such as Huntington’s disease or certain cancers. Results can inform personal health choices and preventive measures.
Carrier testing determines if a person carries a gene change for a recessive genetic disorder they could pass to their children. Carriers typically do not show symptoms but can transmit the condition if their partner is also a carrier. This screening is often recommended for those planning or already pregnant, offering information about a child’s potential risk.
Pharmacogenomics explores how a person’s genetic makeup influences their response to specific medications. By analyzing genetic variants, this testing helps healthcare providers select the most effective drugs and appropriate dosages, potentially minimizing adverse side effects. This field is a component of precision medicine, tailoring treatments based on an individual’s unique genetic profile.
Newborn screening is performed shortly after birth to detect genetic disorders. Early identification of conditions like phenylketonuria (PKU) or sickle cell disease allows for prompt treatment that can reduce disease severity or prevent long-term disability. Nearly all newborns in the United States are screened for a panel of conditions, though the specific disorders tested vary by state.
The Genetic Testing Procedure
Genetic testing typically begins with a healthcare provider arranging the test, often during a genetic consultation. Sample collection is usually straightforward and minimally invasive. Common samples include blood, saliva, cheek cells collected with a swab, or other tissues like skin. For newborns, a small blood sample is collected from a heel prick.
Once collected, the sample is sent to a specialized laboratory for analysis. Technicians extract the DNA from the cells, which contains the genetic information to be examined. Using advanced techniques like DNA sequencing, the laboratory looks for specific changes in chromosomes, genes, or proteins relevant to the suspected condition. The results are then compiled into a written report and sent back to the ordering healthcare provider or directly to the patient, depending on the testing arrangement.
Interpreting Genetic Test Results
Genetic test results typically fall into one of three categories. A positive result indicates the laboratory identified a specific genetic change known to cause a disease or increase risk. This finding may confirm a diagnosis, identify a person as a carrier, or suggest an elevated risk for conditions like certain cancers. However, a positive result for a predictive test often cannot determine the exact risk of developing a disorder or predict its severity or progression.
A negative result means the laboratory did not find the specific genetic change. This suggests a person is not affected by a particular disorder, is not a carrier, or does not have an increased risk for a certain disease. A negative result does not guarantee a person will never develop a disease, as some tests may not detect all possible genetic changes, or other genetic or environmental factors could still play a role.
A Variant of Uncertain Significance (VUS) means the laboratory found a genetic change, but there is insufficient scientific information to determine if it is associated with a disease. These variants are often rare, and their effect on health is not fully understood. A VUS result typically does not lead to immediate changes in medical care. Further research or testing of family members may be necessary to clarify its meaning. Discussing all genetic test results with a doctor or genetic counselor is important to understand their implications.
Clinical Versus Direct-to-Consumer Testing
Genetic testing can be obtained through clinical testing or direct-to-consumer (DTC) testing. Clinical genetic testing is ordered by a healthcare provider, such as a doctor or genetic counselor. It is used for diagnosis, guiding medical decisions, or assessing disease risk based on a patient’s medical and family history. These tests are comprehensive, targeting specific gene variants with established links to diseases, and results are interpreted within a medical context, often including genetic counseling.
Direct-to-consumer (DTC) genetic tests are purchased directly by individuals online or in retail stores, without a healthcare provider’s order. These tests commonly provide information about ancestry, recreational traits, or general wellness. While some DTC tests offer insights into health-related predispositions, they typically look for a limited number of common genetic variants. They may not provide the comprehensive analysis or medical oversight found in clinical testing.
For health-related findings from DTC tests, it is recommended to confirm results with a clinical genetic test performed by a healthcare professional before making medical decisions. Clinical tests use advanced technology and are designed for higher accuracy and reliability. Consulting a healthcare provider or genetic counselor after DTC testing can help interpret results and discuss next steps.