Genetic tests: opportunities and restrictions on health assessment

Genetic tests: opportunities and restrictions on health assessment

I. Fundamentals of genetic testing:

A. What is a genetic test?

A genetic test is an analysis of DNA, RNA, chromosomes or proteins in order to identify genetic changes associated with diseases or predisposition to them. These changes may include:

1. Mutations: Changes in the sequence of DNA. Mutations can be point (replacement of one nucleotide), deeds (loss of a DNA section), inerts (insertion of a DNA site) or larger changes, such as duplication or inversion.

2. Chromosomal abnormalities: Changes in the quantity or structure of chromosomes. Examples include trisomies (additional chromosome, for example, Down syndrome), monosomy (lack of chromosome) and translocation (transfer of a chromosome section to another chromosome).

3. Polymorphisms: Variations in the DNA sequence, which are relatively common in the population (usually more than 1%). Many polymorphisms do not cause diseases, but some can affect the risk of certain diseases or to reaction to drugs.

B. Types of genetic tests:

Genetic tests are classified according to various criteria, including by the purpose of testing, the type of material analyzed and the analysis method. The main types include:

1. Diagnostic tests: They are used to confirm or exclude the diagnosis of a genetic disease in a person with signs and symptoms of this disease. For example, analysis for mutations in the CFTR gene for diagnosis of cystic fibrosis.

2. Predictive tests: They are used to assess the risk of developing a genetic disease in the future, even if a person has no signs and symptoms of the disease at present. For example, analysis for mutations in the BRCA1 and BRCA2 genes to assess the risk of developing breast cancer and ovary.

3. Presumptomatic tests: They are used to identify genetic mutations that inevitably lead to the development of the disease in the future if a person lives to a certain age. For example, analysis for mutations in the HTT gene for diagnosis of hydrofoil disease.

4. Narrow tests: They are used to determine whether a person is a carrier of a genetic mutation that can be transmitted to his children. Harshes usually have no signs and symptoms of the disease, but if both parents are carriers of mutations in the same gene, they have a risk of a child’s birth with this disease. Examples include an analysis for the carriage of cystic fibrosis, sickle cell anemia and Tey-Saxi disease.

5. Pharmacogenetic tests: They are used to determine how the genetic composition of a person affects his reaction to drugs. The results of these tests can help doctors choose the most effective and safe drug and a dose for a particular patient. For example, analysis for polymorphisms in the CYP2C19 and CYP2D6 genes, which affect the metabolism of many drugs.

6. Prenatal tests: Used to detect genetic diseases in the fetus during pregnancy. There are invasive methods (for example, amniocentesis and choriona villi biopsy) and non -invasive methods (for example, non -invasive prenatal screening – NIPS) that analyze the fetal DNA circulating in the mother’s blood.

7. Neonatal screening: It is used to detect genetic diseases in newborns. Timely identification and treatment of these diseases can prevent serious complications and improve the quality of life of the child. Examples include screening for phenylketonuria, congenital hypothyroidism and cystic fibrosis.

8. Tests for establishing paternity: Used to confirm or exclude paternity based on DNA analysis.

9. Tests for determining ethnic origin: Analyze certain genetic markers to evaluate the ethnic origin of man. These tests can be interesting for people who want to learn more about their history and ancestors.

C. Methods of conducting genetic tests:

There are many methods of conducting genetic tests, each of which has its own advantages and disadvantages. The main methods include:

1. DNA sequencing: Determination of the exact sequence of nucleotides in DNA. Sequencing can be used to identify mutations, polymorphisms and other genetic changes. There are various types of sequencing, including Senger sequencing (classic method) and a new generation security (NGS), which allows to secrete large volumes of DNA faster and cheaper.

2. Polymerase chain reaction (PCR): A method that allows you to repeatedly copy a certain DNA section. PCR is used to amplifying DNA before analysis, which allows you to increase the amount of DNA for more accurate detection of genetic changes.

3. Fluorescence hybridization in situ (fish): A method that uses fluorescently labeled DNA zonds to identify certain DNA sequences or chromosomes in cells. Fish is used to detect chromosomal abnormalities, such as trisomy and translocation.

4. Chromosomal micrust analysis (CMA): The method that uses microchips to identify deletions and duplications of DNA sections (copy numbers of options). CMA allows you to identify smaller chromosomal abnormalities than a traditional karyotype.

5. Cariotipirani: A method that allows you to visualize chromosomes under a microscope. Cariotal is used to detect chromosomal abnormalities, such as trisomy, monosomia and translocation.

D. The process of genetic testing:

The process of genetic testing includes several stages:

1. Consultation with a geneticist: The geneticist evaluates the history of the patient’s disease and his family, discusses the goals and limitations of genetic testing, selects the most suitable test and explains possible results.

2. Sample collection: For genetic testing, a sample of blood, saliva, tissue or hair is usually required.

3. Sample analysis: The sample is sent to the genetic laboratory, where the analysis of DNA, RNA, chromosomes or proteins is carried out.

4. Interpretation of the results: The geneticist interprets the results of the analysis and explains them to the patient.

5. Consultation after testing: The geneticist discusses with the patient the test results, their importance to the health of the patient and his family, as well as possible treatment and prevention options.

II. Possibilities of genetic testing in health assessment:

A. Diagnosis of genetic diseases:

Genetic tests play an important role in the diagnosis of genetic diseases. They can help confirm the diagnosis, determine a specific mutation that causes the disease, and exclude other possible causes of the disease. For example, a genetic test can confirm the diagnosis of cystic fibrosis by identifying mutations in the CFTR gene. Early and accurate diagnosis allows you to start treatment and improve the prognosis for patients with genetic diseases.

B. Assessment of the risk of developing diseases:

Genetic tests can help evaluate the risk of developing certain diseases in the future. This is especially useful for diseases that have a genetic predisposition such as breast cancer, ovarian cancer, Alzheimer’s disease and cardiovascular diseases. Identification of increased risk allows you to take preventive measures, such as a change in lifestyle, regular examinations and preventive treatment. For example, women with mutations in the BRCA1 and BRCA2 genes can consider the possibility of preventive mastectomy and ovariectomy to reduce the risk of breast cancer and ovaries.

C. Pharmacogenetics and personalized medicine:

Pharmacogenetic tests make it possible to determine how the genetic composition of a person affects his reaction to drugs. This allows doctors to choose the most effective and safe drug and a dose for a particular patient, which leads to an improvement in treatment results and reduce the risk of side effects. For example, patients with certain polymorphisms in the CYP2C19 gene can respond worse to clopidogrel (anti -signs), and they may need an alternative drug.

D. Family planning and reproductive health:

Genetic tests play an important role in family planning and reproductive health. Posit tests allow you to determine whether the parents are carriers of genetic mutations that can be transmitted to their children. Prenatal tests allow you to detect genetic diseases in the fetus during pregnancy. The results of these tests can help parents make informed decisions on family planning, the use of auxiliary reproductive technologies (for example, extracurporeal fertilization with preimplantation genetic diagnostics) and pregnancy management.

E. Identification of a predisposition to sports achievements:

Some genetic tests explore genes associated with physical endurance, strength and other sports qualities. The results of these tests can help athletes and trainers develop individual training programs in order to maximize the genetic potential. However, it is important to note that sports achievements depend not only on genetics, but also on training, nutrition and other factors.

III. Restrictions on genetic testing in health assessment:

A. Incomplete penetrance and variable expressiveness:

Not all people with a genetic mutation will definitely get sick. Some mutations have incomplete penetrance, which means that not all people with this mutation show signs and symptoms of the disease. In addition, even if a person gets sick, the expressiveness of the disease can vary, which means that symptoms can be different in severity in different people. This makes it difficult to predict the exact risk of developing the disease based on the results of the genetic test.

B. Polygenic diseases and genes interaction:

Many common diseases, such as cardiovascular diseases, diabetes and cancer, are polygenic, that is, they are caused by the interaction of many genes. Genetic tests usually analyze a limited number of genes, so they cannot fully evaluate the risk of developing these diseases. In addition, the interaction of genes can be complex and difficult to predict.

C. The influence of environmental factors:

The development of many diseases depends not only on genetics, but also on environmental factors, such as nutrition, lifestyle, exposure to toxins and infections. Genetic tests cannot take into account all these factors, so they cannot give a complete picture of the risk of developing the disease.

D. The limited information about some genes:

Not all genes associated with diseases are well studied. For some genes, it is known that they are associated with an increased risk of development of the disease, but the exact mechanism of this influence is unclear. In addition, for some genetic options, it is not known how they affect the risk of developing the disease. This complicates the interpretation of the results of genetic tests and can lead to wrong conclusions.

E. The possibility of false positive and false negative results:

Genetic tests, like any other medical tests, are not absolutely accurate. There is a likelihood of false positive results (when the test shows the presence of a mutation that is actually not) and false negative results (when the test does not show the presence of a mutation that is actually there). This can lead to improper diagnosis and treatment.

F. Ethical and social issues:

Genetic testing raises a number of ethical and social issues. These include issues of confidentiality of genetic information, discrimination based on genetic results, the psychological impact of testing results and the right to informed consent. It is important that genetic testing is carried out in compliance with ethical principles and taking into account the interests of the patient.

G. High cost and limited availability:

Genetic tests can be expensive and not always available to everyone who needs them. The cost of genetic testing varies depending on the type of test, the analysis method and the laboratory in which testing is carried out. The limited availability of genetic testing can create inequality in access to medical care.

IV. The use of genetic testing in various fields of medicine:

A. Oncology:

Genetic tests are widely used in oncology to assess the risk of cancer, diagnosis of cancer, the choice of treatment and monitoring the effectiveness of treatment. Examples include analysis for mutations in BRCA1 and BRCA2 genes to assess the risk of breast cancer and ovary cancer, analysis for mutation in Kras and EGFR genes for the selection of lung cancer, and analysis for the minimum residual disease (mob) for monitoring the effectiveness of leukemia treatment.

B. Cardonallogy:

Genetic tests are used in cardiology to assess the risk of developing cardiovascular diseases, diagnosis of genetic cardiomyopathy and arrhythmias, and treatment selection. Examples include analysis of polymorphisms in genes associated with cholesterol metabolism, to assess the risk of atherosclerosis, analysis for mutation in genes encoding the proteins of the heart muscle, for the diagnosis of genetic cardiomyopathy, and analysis for mutation in genes that encode ion channels of the heart, to diagnose genetic arrhythmias.

C. Neurology:

Genetic tests are used in neurology for the diagnosis of genetic neurological diseases, such as hydrofoil, muscle dystrophy of Duchenna and spinal muscle atrophy, and to assess the risk of Alzheimer’s disease and Parkinson’s disease.

D. Pediatrics:

Genetic tests are widely used in pediatrics to diagnose genetic diseases in children, such as cystic fibrosis, phenylketonuria and Down syndrome, and for neonatal screening.

E. Reproductive medicine:

Genetic tests are used in reproductive medicine for family planning, conducting prenatal screening and diagnosis, and the use of auxiliary reproductive technologies.

V. The future of genetic testing:

A. Development of new technologies:

In the future, genetic testing will become more accurate, fast and cheap due to the development of new technologies, such as new generation sequencing (NGS), CRISPR-CAS9 and liquid biopsy.

B. Expanding use in personalized medicine:

Genetic testing will be increasingly used in personalized medicine to select the most effective and safe treatment for each patient.

C. Integration with great data and artificial intelligence:

Genetic data will be integrated with great data and artificial intelligence to identify new genetic connections with diseases and develop new diagnostic and treatment methods.

D. Expanding availability and reducing value:

In the future, genetic testing will become more affordable and cheap, which will allow more people to use its advantages.

VI. Rules for using genetic testing:

A. Consultation with a geneticist:

Before conducting genetic testing, it is necessary to consult a geneticist to discuss the goals and restrictions of testing, choose the most suitable test and get information about possible results.

B. Informed consent:

Before conducting genetic testing, it is necessary to obtain informed consent of the patient, which confirms that the patient understands the goals, risks and advantages of testing.

C. Privacy of genetic information:

It is necessary to observe the confidentiality of the patient’s genetic information and protect it from unauthorized access.

D. Ethics of the use of genetic information:

Genetic information should be used ethically in the interests of the patient, and not for discrimination or other unlawful purposes.

E. Interpretation of results with caution:

The results of genetic testing should be interpreted with caution and taking into account the clinical picture of the patient and his family history. It is necessary to remember the possibility of incomplete penetrance, variable expressiveness and the influence of environmental factors.

By thoroughly addressing these points, this article offers a detailed and informative overview of genetic testing, its applications, and limitations in healthcare assessment.