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A genetic test is a type of medical test that detects changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or deny a suspicious genetic condition, or can help determine a person’s chances of developing or overcoming a genetic disorder. There are currently more than 1,000 genetic tests, and that number is growing by the day.
Different methods can be used for genetic testing:
Molecular genetic testing (or gene testing) examines single genes or short DNA sequencing to identify variations or mutations that cause a genetic disease.
Chromosome genetic testing examines all chromosomes in terms of digital and structural changes, such as whether there are major genetic changes, such as an additional chromosome copy that causes a genetic condition.
Genetic testing is voluntary. The decision to pass the test is entirely individual, as the test has benefits, limitations and risks. It is very important for a geneticist to make a decision by learning about the pros and cons of the test.
Genetic testing can provide information about a person’s genes and chromosomes. The types of tests available are:
Newborn Genetic
Screening Test Newborn screening is used soon after birth to identify genetic disorders that can be treated soon after birth. These tests are of great importance, especially in infants with suspected metabolic disease. Babies with suspected metabolic disease may unfortunately be lost until the diagnosis is made. For this, a quick decision should be made and blood should be taken from the baby for genetic examinations. In this way, even if the baby is lost, it will be possible to inform the family about the risks they may encounter in other pregnancies.
Diagnostic Test
Diagnostic testing is used to identify a particular genetic or chromosomal condition. In many cases, genetic testing is used to confirm the diagnosis when a particular condition is suspected based on physical signs and symptoms. Diagnostic tests can be done before birth or at any time during a person’s life, but they are not available for all genes or all genetic conditions. The results of a diagnostic test can affect a person’s choices about their health care and management of the disorder.
Carrier Testing
Carrier testing is used to identify people who carry one copy of a gene mutation that causes a genetic disorder when present in duplicate. This type of test is offered to individuals with a family history of a genetic disorder and to people in certain ethnic groups at risk for certain genetic conditions. If both parents are tested, the test can provide information about a couple’s risk of having a child with the genetic condition. Diseases such as thalassemia, FMF and hearing loss are common, and the family can be informed about the risks they will encounter in possible pregnancies by testing these clinics.
Prenatal Tests
Prenatal testing is used to detect changes in the genes or chromosomes of the fetus. This type of testing is offered during pregnancy when the baby has an increased risk of having a genetic or chromosomal disorder. In some cases, prenatal testing can reduce a couple’s uncertainty or help them make decisions about pregnancy. However, it cannot identify all possible inherited disorders and birth defects.
Preimplantation Test (PGT)
Preimplantation testing, also called preimplantation genetic diagnosis (PGD), is a special technique that can reduce the risk of having a child with a certain genetic or chromosomal disorder. It is used to detect genetic changes in embryos created using assisted reproductive techniques such as in vitro fertilization. In vitro fertilization involves removing egg cells from a woman’s ovaries and fertilizing them with sperm cells outside the body. To perform a preimplantation test, a small number of cells are taken from these embryos and tested for certain genetic changes. To initiate pregnancy, only embryos are implanted in the uterus without these changes.
Predictive and Presymptomatic Testing
Predictive and presymptomatic types of testing are used to detect gene mutations associated with disorders that appear after birth, often later in life. These tests can help people who have a family member with a genetic disorder, but no features of the disorder at the time of testing. Predictive testing can identify mutations that increase a person’s risk of developing a genetically based disorder, such as certain types of cancer. Presymptomatic testing can determine whether a person will develop a genetic disorder such as hereditary hemochromatosis before any signs or symptoms appear. Predictive and presymptomatic test results can provide information about a person’s risk of developing a particular disorder and to assist in making decisions about medical care.
Genetic testing should usually be done as part of a genetic consultation.
Genetic testing is performed on a sample of blood, hair, skin, amniotic fluid (the fluid that surrounds the fetus during pregnancy), or another tissue sample. For example, a procedure called a buccal smear uses a small brush or cotton swab to collect a sample of cells from the inner surface of the cheek.
These sample types vary according to the test to be performed. For genetic tests, fasting does not matter.
Before performing genetic testing, it is important for a person to understand the testing procedure, the benefits and limitations of the test, and the possible consequences of the test results. The process of educating a person about the exam and obtaining permission is called informed consent.
Families can have many health problems. Doctors call this family situation “genetic” or “hereditary”. If you have a parent or grandmother with a serious health condition, you may want to know if you are at high risk for the disease. In the same way, you may want to know if you or your partner can inherit for your baby. You can consider genetic consultation to get answers to these questions. Genetics specialists do not only explain the risks of inherited condition being passed from one generation to the next, but they also can help to resolve the emotional side of how genetic conditions affect a family.
If you are planning to have a child and want to learn more about screening for genetic conditions.
A woman who has difficulty in conceiving or who has lost several children.
A mother with a child with a genetic defect and worried about it happening again.
If you are interested in your family’s genetic diseases.
Search for information about common genetic conditions in certain ethnic groups, such as anemia, FMF.
Genetic test reports are not always easy to understand. These results must first be interpreted and explained to the patient or physician by the geneticist. Therefore, it is important for the physician to ask patients and their families questions about the potential significance of genetic test results before and after the test is performed. When interpreting test results, physicians consider a person’s medical history, family history, and the type of genetic testing performed.
A positive test result means that the lab has found a change in a particular gene, chromosome, or protein. Depending on the purpose of the test, this result may confirm a diagnosis, determine that a person is a carrier of a particular genetic mutation, have an increased risk of developing a future disease (such as cancer), or need additional testing. Because family members have some genetic material in common, a positive test result may also have implications for certain blood relatives of the person being tested. It is important to note that a positive result of a predictive or presymptomatic genetic test often cannot fully determine the risk of developing a disorder. Also, healthcare professionals typically cannot use a positive test result to predict the course or severity of a condition.
A negative test result means that the lab did not find a change in a gene, chromosome, or protein being examined. This result may indicate that a person is not affected by a particular disorder, is not a carrier of a particular genetic mutation, or is not at increased risk of developing a particular disease. However, it is possible for the test to miss a genetic change that causes the disease because many tests cannot detect all the genetic changes that can cause a particular disorder. Further testing may be required to confirm a negative result.
In some cases, a test result may not provide any useful information. Such a conclusion is called informative or inconclusive. Unidentified test results sometimes occur because everyone has natural variations in their DNA that do not affect health, called polymorphisms. If a genetic test finds a change in DNA that has not been associated with a disorder in other people, it may be difficult to tell whether it is a natural polymorphism or a disease-causing mutation. An unconscious result cannot confirm or determine a specific diagnosis and indicate that a person is at increased risk of developing a disorder. In some cases, testing other affected and unaffected family members can help clarify such results.
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