Définition et aperçu
Genetic testing, sometimes referred to as DNA testing, is a medical term that refers to a number of tests performed to determine changes and abnormalities in the genetic composition of a person using samples of chromosomes, genes, and proteins. One common example is the molecular genetic test in which mutations are detected in short DNA sequences or single genes. Another type, the chromosomal genetic test, is the analysis of chromosomes or longs strands of DNA to evaluate the cause of a certain genetic condition. These tests are voluntary and performed in laboratories, with results interpreted by geneticists.
Qui devrait subir et résultats attendus
Understandably, genetic testing is not advisable for all types of people. Since it involves the assessment of mutation in the genetic makeup of a person, the results would also have an impact on the rest of the family who likely share the same genetic composition.
Families with a higher likelihood of developing a certain type of disease are advised to undergo DNA testing. The results would be beneficial in determining who are at risk and can be used to make informed lifestyle decisions. A particular person who may be a carrier of an inherited disease and those belonging to certain ethnic groups that might also be predisposed to a specific medical condition can also undergo the tests.
In some instances, physicians who have a difficulty diagnosing a particular medical condition advise their patients to undergo DNA testing to come up with an effective treatment plan.
Pregnant women carrying fetuses at risk for certain disorders are also advised to undergo genetic testing to identify conditions that would impact their development.
A positive result confirms a previous diagnosis or the patient’s risk of a certain inherited disease. It could also determine if the person is a carrier of a mutated gene. It could not, however, predict the severity of a certain condition nor its outcome.
A negative result, on the other hand, would indicate that no mutation or change was detected in a specific gene, DNA sequence, or protein tested. This means that the person is not a carrier, not at risk, nor is affected by a specific disease or disorder.
In some cases, tests might give out uninformative, ambiguous results in which the detected DNA change is not associated with any medical disorder in other people. This typically requires further testing to get conclusive and clear results.
Comment fonctionne la procédure ?
Genetic testing typically starts with the collection of either one or a combination of the following biological samples:
- Blood extracted from a vein or pricked from the heel of a newborn
- Amniotic fluid extracted from the uterus of a Enceinte woman
- Tissues from specific body parts or organs
- Swab samples from the inside of a cheek
- Other biological samples such as hair, skin, or body fluids
Complications et risques possibles
While there are several benefits associated with genetic testing, there are also risks and possible complications.
One is the emotional impact of genetic testing. Knowing that the person or a loved one can develop a debilitating or fatal disease could create feelings of grief or dépression. For this reason, those who undergo genetic testing are advised to consult a genetic counselor to help them deal with the whole process. A professional genetic counselor would be able to answer questions and provide advice on how to deal with the test results.
Genetic testing cannot also provide comprehensive information about the disease a person is at risk for. Up to a certain point, the results would help in the prevention and management of a certain condition but cannot definitely predict how or when a disease would develop and to what extent.
In a broader sense, genetic testing could provide an avenue for discrimination by employers or insurance providers who might opt not to provide benefits to people who are predisposed to or at risk of certain conditions.
Genetic testing might also take a financial toll on families, with costs ranging from hundreds to thousands of dollars. Some of the tests might be covered by medical insurance but others require out-of-pocket expenses.
Simpson JL, Holzgreve W, Driscoll DA. Conseil génétique et dépistage génétique. Dans : Gabbe SG, Niebyl JR, Simpson JL, eds. Obstétrique : grossesses normales et problématiques. 6e éd. Philadelphie, Pennsylvanie : Elsevier Churchill Livingstone ; 2012 : chap. 10.
Simpson JL, Richards DA, Otao L, Driscoll DA. Diagnostic génétique prénatal. Dans : Gabbe SG, Niebyl JR, Simpson JL, eds. Obstétrique : grossesses normales et problématiques. 6e éd. Philadelphie, Pennsylvanie : Elsevier Churchill Livingstone ; 2012 : chap. 11.
**What is Genetic Testing: Overview, Benefits, and Expected Results**
Genetic testing analyzes an individual’s DNA or genes to identify variations (mutations) associated with inherited or acquired conditions. It enables healthcare providers to:
* Diagnose and assess the risk of genetic diseases
* Determine appropriate treatment plans
* Provide personalized care based on individual genetic makeup
* Guide lifestyle modifications to mitigate risks
**Benefits of Genetic Testing**
* **Early detection and diagnosis:** Identifying genetic variations can alert individuals to potential health issues, allowing for timely interventions and preventive measures.
* **Personalized medicine:** Genetic testing provides insights into how an individual responds to certain medications and treatments, optimizing healthcare outcomes.
* **Reproductive planning:** Carrier testing can inform couples about the risk of passing on genetic disorders to their children, enabling informed family planning decisions.
* **Forensic investigations:** Genetic fingerprinting plays a crucial role in criminal investigations, identification of remains, and paternity testing.
The results of genetic testing can vary depending on the specific test and the condition being evaluated. Here are some common outcomes:
* **Negative result:** The test does not detect any genetic variations of concern.
* **Positive result:** The test identifies a variation associated with an increased risk of a specific condition.
* **Variant of uncertain significance (VUS):** The test result shows a variation that has not been well-studied or has conflicting interpretations, requiring further research or testing.
* **Mosaicism:** Only some cells in the body contain the genetic variation, which may impact the severity and prognosis of the condition.
* **Unexpected findings:** Genetic testing may also uncover incidental findings unrelated to the primary reason for the test, and these results require appropriate communication and counseling.
**How to Prepare for Genetic Testing**
Before undergoing genetic testing, it is essential to:
* Understand the purpose and potential benefits of the test
* Discuss the implications of positive and negative results
* Consider the psychological impact and privacy concerns
* Consult with a genetic counselor or healthcare provider to weigh the pros and cons
**Future of Genetic Testing**
Advancements in technology continue to revolutionize genetic testing. Whole-genome sequencing, for example, offers comprehensive genetic information, aiding in the detection of rare and complex conditions. As research progresses, we can expect even more personalized and accurate genetic testing in the future.