Genetic testing: what you need to know before

Genetic Testing: What you need to know before you decide on analysis

Genetic testing, also known as genetic screening or DNA testing, is an analysis of DNA samples to identify changes or mutations in genes, chromosomes or proteins. These changes may indicate an increased risk of developing certain diseases, a predisposition to them, or even confirm the presence of an existing disease. With the development of science, genetic testing is becoming more accessible and common, offering people the opportunity to better understand their heredity and make reasonable decisions about their health and the health of future generations. However, before deciding on genetic testing, it is important to carefully understand its types, capabilities, restrictions and ethical considerations.

1. Types of genetic testing:

Genetic testing covers a wide range of analyzes, each of which is intended for specific purposes and uses different methods. The main types of genetic testing include:

• Diagnostic testing: It is carried out to confirm or exclude the diagnosis of a genetic disease in a person who already has symptoms or signs of this disease. This type of testing can help determine the specific genetic cause of the disease, which, in turn, can affect the choice of treatment and forecasts. For example, diagnostic testing is often used to confirm the diagnosis of cystic fibrosis, Down syndrome or phenylketonuria. Samples used for diagnostic testing may include blood, saliva, tissues or other biological materials. The results of diagnostic testing are crucial for the development of an individual treatment plan and support for the patient and his family.

• Predictive and predisposing testing: It is used to identify genetic mutations that increase the risk of developing certain diseases in the future. Predictive testing is used when the mutation is high -pentrant, that is, it will almost certainly lead to the development of the disease, for example, mutations in the BRCA1 and BRCA2 genes, which significantly increase the risk of developing breast cancer and ovaries. The predisposing testing reveals genes that only increase the likelihood of developing the disease, but do not guarantee its appearance. An example is testing on genes associated with Alzheimer’s disease or type 2 diabetes. The results of predictive and predisposing testing allow people to take preventive measures, such as a change in lifestyle, regular examinations, and even preventive operations to reduce the risk of the development of the disease or detect it at an early stage.

• Testing of carriage: Determines whether a person is a carrier of a gene that causes a recessive genetic disease. As a rule, carriers do not show any symptoms of the disease, but can convey the mutant gene to their children. Testing of carriage is especially important for couples planning pregnancy, especially if they have a family history of genetic diseases or belong to ethnic groups with an increased risk of certain diseases. For example, testing for the carriage of a cystic fibrous gene is recommended for couples planning pregnancy, since both parents should be carriers so that the child has the opportunity to be born with this disease. The results of testing of carriage allow pairs to make conscious decisions on reproductive health, such as pre -implantation genetic diagnostics (PGD) or the use of donor sperm or eggs.

• Prenatal testing: It is carried out during pregnancy to assess the risk of genetic diseases in the fetus. There are several types of prenatal testing, including:

  • Screening tests: Non -invasive tests, such as the combined screening of the first trimester (ultrasound examination and blood test) and non -invasive prenatal test (NIPT), which analyzes the fetal DNA circulating in the mother’s blood, to evaluate the risk of chromosome anomalies, such as Down syndrome. Screening tests do not diagnose, but determine the need for further diagnostic testing.
  • Diagnostic tests: Invasive tests, such as amniocentesis (an amniotic fluid fence) and choriona biopsy (placenta tissue), allow you to obtain a fetal DNA sample for more accurate genetic analysis. Diagnostic tests are associated with a small risk of termination of pregnancy, therefore, they are carried out only if there are certain indications, such as a positive result of a screening test or a family history of genetic diseases.

• Neonatal screening: It is carried out shortly after the birth of a child to identify certain genetic diseases that can be successfully cured or prevented if they are detected at an early stage. In most countries, neonatal screening is mandatory and includes an analysis of a small blood sample taken from the heel of the newborn. The most common diseases detected by neonatal screening include phenylketonuria, hypothyroidism and cystic fibrosis. Early identification and treatment of these diseases can prevent serious health problems and improve the quality of life of the child.

• Pharmacogenetic testing: Analyzes genes that affect a person’s reaction to certain drugs. The results of pharmacogenetic testing can help doctors choose the most effective medicine and the optimal dose for a particular patient, minimizing the risk of side effects and increasing the effectiveness of treatment. Pharmacogenetic testing is especially useful when prescribing drugs that have a narrow therapeutic range or can cause serious side effects, such as antidepressants, anticoagulants and antitumor drugs.

• Identification testing: It is used to establish kinship, for example, to determine paternity or motherhood, as well as in forensics to identify the personality of criminals or victims. Identification testing is based on the analysis of unique genetic markers who are inherited from parents to children.

2. Genetic testing methods:

There are many methods of genetic testing, each of which has its own advantages and disadvantages. The choice of the method depends on the purpose of testing, the availability of DNA sample and the cost of analysis. The main methods of genetic testing include:

• DNA sequencing: Determines the sequence of nucleotides (construction blocks of DNA) in a certain gene or in the entire genome. DNA sequencing is the most accurate and comprehensive method of genetic testing, which allows you to identify almost any genetic changes. There are several types of DNA sequencing, including Senger sequencing (the traditional method used to analyze individual genes), sequencing of the new generation (NGS) (high -performance method that allows you to analyze many genes at the same time or the entire genome) and sequencing of exoma (analysis of only encoding genome sections, exosons).

• Polymerase chain reaction (PCR): A method used for amplification (multiplication) of a certain DNA section. PCR allows you to get a sufficient amount of DNA for further analysis, even if the initial amount of DNA is very small. PCR is often used in diagnostic testing to detect infectious diseases, as well as to prepare DNA samples for sequencing.

• Fluorescence hybridization in situ (fish): A method used to visualize certain genes or chromosomes in cells. Fish uses fluorescent probes that are associated with certain DNA sections, allowing you to identify anomalies of the chromosomal structure, such as deletions, duplication or translocation. Fish is often used in prenatal diagnosis to detect chromosomal anomalies, such as Down syndrome.

• Chromosomal micrust analysis (HMA): The method used to detect deeds and duplications (changes in the number of copies) of DNA sections throughout the genome. HMMs allows you to identify smaller delections and duplications than a traditional carioter (analysis of chromosomes under a microscope). HMAs are often used in diagnostic testing in children with developmental retardation or congenital anomalies.

• Sauzern Blotting: The method used to identify specific DNA sequences in the sample. Sauser-blotting includes DNA breakdown into fragments using restricted endonuclease, separation of fragments by size using electrophoresis, transferring DNA to a membrane and hybridization with a swording DNA probe, and a complementary desired sequence. Sauser-blotting is used less often than other methods of genetic testing, but can still be useful for identifying complex genetic changes.

3. Indications for genetic testing:

Indications for genetic testing are determined individually in each case, given the family history, the presence of symptoms and the purpose of testing. The main indications for genetic testing include:

• Family history of genetic diseases: If the family has cases of genetic diseases, testing can help determine if you have a risk of developing this disease or transferring it to your children. It is especially important to take into account the family history of diseases that appear at an early age or have high penetrance.

• Symptoms of a genetic disease: If you have symptoms that may indicate a genetic disease, diagnostic testing can help confirm or exclude the diagnosis.

• Pregnancy planning: Testing of carriage can be useful for couples planning pregnancy to determine the risk of a child with a recessive genetic disease. Prenatal testing can be recommended by pregnant women, especially if they have a family history of genetic diseases or they are older than 35 years.

• Determining the risk of the development of the disease: The predictive and predisposing testing can be useful for people who want to know their risk of developing certain diseases, such as cancer, Alzheimer’s disease or diabetes.

• The choice of drug therapy: Pharmacogenetic testing can help doctors choose the most effective medicine and dose for a particular patient, minimizing the risk of side effects.

4. The process of genetic testing:

The process of genetic testing usually includes the following stages:

• Consultation with a geneticist: Before conducting genetic testing, it is recommended to consult a geneticist or other qualified medical specialist. The geneticist will explain the objectives of testing, types of tests that are available, possible results and their interpretation, as well as ethical and legal aspects of testing.

• Sample fence: For genetic testing, a sample of DNA is needed. The most common types of samples include blood, saliva, tissues (for example, a sample of biopsy) and amniotic fluid. The method of sample fence depends on the type of test and can vary from a simple smear from the oral cavity to the invasive procedure, such as amniocentesis.

• Laboratory analysis: A DNA sample is sent to a specialized genetic laboratory for analysis. The laboratory uses various genetic testing methods to detect genetic changes.

• Interpretation of the results: After the analysis is completed, the laboratory provides a report with test results. The interpretation of the results of genetic testing can be complex and requires special knowledge. A geneticist or another medical specialist will explain to you the results of testing, their importance for your health and health of your family, as well as possible options for further actions.

5. Possible results of genetic testing:

The results of genetic testing can be positive, negative or vague.

• Positive result: It indicates that a person has a genetic mutation associated with a certain disease or an increased risk of its development. A positive result does not always mean that a person will necessarily get sick, but indicates the need to conduct further examinations and take preventive measures.

• Negative result: Indicates that a person does not find a genetic mutation that was searched for during testing. A negative result does not always exclude the risk of developing the disease, especially if the family has other genetic mutations or if the disease has a multifactorial nature.

• UNDERSTANDED result (option of an unclear value, VUS): It indicates that a person has a genetic mutation, the value of which is currently unknown to health. VUS may be the result of a rare mutation, not sufficiently studied or mutation, the effect of which has not yet been established on the development of the disease. In such cases, further research and testing of other family members may be required to determine the value of VUS.

6. Genetic test restrictions:

Genetic testing has its restrictions, which must be taken into account before making a decision on its implementation:

• Incomplete information: Genetic testing cannot reveal all genetic mutations associated with a specific disease. Many diseases have a multifactorial nature and depend not only on genetics, but also on environmental and lifestyle factors.

• Vague results: As already mentioned, genetic testing can give vague results, which can cause anxiety and uncertainty.

• Psychological consequences: The results of genetic testing can have a significant impact on the psychological state of a person and his family. A positive result can cause anxiety, fear and depression, and a negative result can create a false sense of safety. It is important to be prepared for possible psychological consequences of testing and be able to get psychological support.

• Discrimination: There is a risk of genetic discrimination when employers or insurance companies use the results of genetic testing to make decisions that discriminate person. In some countries, there are laws that protect people from genetic discrimination, but it is important to know about the possible risk.

7. Ethical and legal aspects of genetic testing:

Genetic testing raises a number of important ethical and legal issues that must be taken into account:

• Confidentiality: The results of genetic testing are confidential information and should be protected from unauthorized access.

• Informed consent: Before conducting genetic testing, it is necessary to obtain informed consent of a person. Informed consent means that a person should be completely informed about testing, types of tests, possible results and their interpretation, risks and advantages of testing, as well as his rights.

• Right to ignorance: A person has the right to refuse to conduct genetic testing or to obtain test results. This right to ignorance should be respected.

• Reproductive solutions: The results of genetic testing can affect the reproductive decisions of a person or pair. It is important that these decisions are based on complete and accurate information and that people receive support and consultations when making these decisions.

• Children testing: Genetic testing of children raises complex ethical issues. In general, genetic testing of children is recommended only in cases where it is necessary for their health and well -being, for example, to diagnose the disease or for the choice of treatment. Testing of children for diseases that appear in adulthood is usually not recommended, since the child cannot give informed consent to testing.

8. Where to go through genetic testing:

Genetic testing can be held in various medical institutions, including:

• Medical and genetic consultations: Specialized centers where genetics and other medical specialists work who can provide consultation on genetic testing, samples and interpretation of results.

• Clinical laboratories: Laboratory accredited for genetic testing.

• Hospitals and clinics: Some hospitals and clinics offer genetic testing as part of a comprehensive examination or treatment.

• Direct-to-Consumer (DTC) Genetic Testing: Testing that can be ordered directly via the Internet, without consulting a doctor. DTC testing can be useful for obtaining general information about its heredity, but it is important to remember that the results of DTC testing are not always accurate and may require confirmation in the clinical laboratory. In addition, the interpretation of the results of DTC testing can be complex and requires special knowledge.

9. The cost of genetic testing:

The cost of genetic testing can vary depending on the type of test, analysis method, laboratory testing, and the country in which testing is carried out. Some genetic tests are covered with medical insurance, especially if they are carried out as medical reasons. It is important to clarify with your insurance company what genetic tests are covered by your insurance and what conditions must be fulfilled to obtain coating. If the genetic test is not covered with insurance, you will have to pay it yourself. The cost of genetic testing can be significant, so it is important to consider this factor when making a decision on its implementation.

10. Final recommendations:

Before deciding on genetic testing, it is recommended to carefully weigh the pros and cons, consult a geneticist or other qualified medical specialist, and get all the necessary information about testing, types of tests, possible results and their interpretation, risks and advantages of testing, as well as ethical and legal aspects of testing. It is important to remember that genetic testing is only one tool in the arsenal of modern medicine, and its results should be considered in combination with other medical data and factors. The adoption of a reasonable decision on genetic testing will help you better understand your heredity and take an active part in maintaining your health and health of future generations.