Genetics and human health: inextricable connection

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Genetics and human health: inextricable connection

1. Fundamentals of human genetics:

Genetics, the science of heredity and variability, plays a fundamental role in determining human health. Each individual inherits the genetic material from his parents, enclosed in DNA molecules, which form chromosomes. These chromosomes contain genes – the main units of heredity, encoding instructions for protein synthesis. Squirrels, in turn, are cell work horses that perform a wide range of functions necessary to maintain life and health.

  • DNA and genes: Deoxyribonucleic acid (DNA) is a double -stability spiral consisting of nucleotides (adenin, guanine, cytosine and thyamin). The sequence of these nucleotides determines the genetic code, which is transcribed in RNA and is subsequently broadcast into the sequence of amino acids forming the protein. Genes are certain areas of DNA containing instructions for the synthesis of a particular protein or functional RNA.
  • Chromosomes: A person has 23 pairs of chromosomes (46 in total), one chromosome from each pair is inherited from each parent. 22 pairs are autosomes (not sexual chromosomes), but 23rd steam are sexual chromosomes (XX for women and XY in men). Chromosomes consist of DNA, tightly packed around proteins called histones.
  • Genome: The human genome is a complete set of genetic information contained in DNA. The decoding of the human genome at the beginning of the 21st century became a revolutionary event that discovered new opportunities for understanding the genetic basis of diseases and developing new methods of treatment.
  • Genotype and phenotype: The genotype is the genetic constitution of the individual, that is, a specific set of genes that he inherits. The phenotype is the observed characteristics of the individual, such as growth, eye color, exposure to diseases and other signs that are the result of the interaction of the genotype and the environment.
  • Heredity and variability: Heredity is the transfer of genetic information from parents to offspring. Variability is differences in genetic information between individuals that arise as a result of mutations, recombination and other processes.

2. Types of genetic diseases:

Genetic diseases are diseases caused by changes in genetic information. They can be caused by mutations in one gene (monogenic diseases), mutations in several genes (polygenic diseases) or chromosomal abnormalities.

  • Monogenic diseases: Monogenic diseases are caused by mutations in one gene. They are usually inherited according to Mendelevsky Laws (autosomal dominant, autosomal-recessive, X-linked dominant or X-seized recessive). Examples of monogenic diseases:
    • MukoviScidoz: Autosomal recessive disease caused by mutations in the CFTR gene, which encodes a protein that regulates the transport of chloride through cell membranes. This leads to the accumulation of thick mucus in the lungs, pancreas and other organs.
    • Sickle -cell anemia: An autosomal recessive disease caused by a mutation in the HBB gene, which encodes beta-globin, a hemoglobin component. The mutation leads to the formation of abnormal hemoglobin, which deforms red blood cells, giving them a sickle form.
    • Phenylketonuria (FCU): Autosomal recessive disease caused by mutations in the PAH gene, which encodes the enzyme phenylaneineinexylase, which is necessary for phenylalanine metabolism. The accumulation of phenylalanine in the body can lead to damage to the brain.
    • Huntington disease: Autosomas and dominant disease caused by a mutation in the HTT gene, which encodes the Hunting protein. The mutation leads to the progressive degeneration of nerve cells in the brain, causing motor, cognitive and psychiatric disorders.
    • Type 1 neurofibromatosis (NF1): Autosomal-dominant disease caused by a mutation in the NF1 gene, which encodes neurofibromin protein. The mutation leads to the formation of tumors (neurofiber) in the nervous system and other problems.
  • Polygenic diseases: Polygenic diseases are caused by mutations in several genes, as well as the influence of environmental factors. They are usually not inherited according to Mendeleev’s laws and have a more complex nature of inheritance. Examples of polygenic diseases:
    • Type 2 diabetes: The disease characterized by insulin resistance and insulin secretion. The development of type 2 diabetes is associated with many genes involved in glucose metabolism, as well as lifestyle factors, such as obesity and insufficient physical activity.
    • Cardiovascular diseases: Heart and blood vessels, such as coronary heart disease, stroke and hypertension. The development of cardiovascular diseases is associated with many genes that affect the level of cholesterol, blood coagulation, inflammation and other factors, as well as with lifestyle factors, such as smoking, malnutrition and insufficient physical activity.
    • Cancer: A group of diseases characterized by uncontrolled growth and spread of abnormal cells. The development of cancer is associated with many genes involved in the regulation of the cell cycle, DNA reparations and apoptosis (programmable cell death). The development of cancer also affects environmental factors, such as smoking, ultraviolet radiation and the effect of chemicals.
    • Autoimmune diseases: Diseases in which the immune system attacks the body’s own tissues. Examples of autoimmune diseases: rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis and Crohn’s disease. The development of autoimmune diseases is associated with many genes affecting the immune response, as well as environmental factors, such as infections and the effect of chemicals.
    • Mental illness: Diseases affecting thinking, mood, behavior and functioning. Examples of mental illness: schizophrenia, bipolar disorder, depression and alarming disorders. The development of mental illness is associated with many genes involved in the development and functioning of the brain, as well as with environmental factors, such as stress and injuries.
  • Chromosomal abnormalities: Chromosomal abnormalities are changes in the amount or structure of chromosomes. They can occur as a result of errors in cell division (meiosis or mitosis). Examples of chromosomal anomalies:
    • Down Syndrome (Trisomy 21): A chromosomal anomaly in which the individual has three copies of the 21st chromosome instead of two. This leads to mental retardation, characteristic features of the face and other problems.
    • Turner syndrome (monosomy x): A chromosomal anomaly in which women have only one X-chromosome instead of two. This leads to low growth, infertility and other problems.
    • Klainfelter syndrome (XXY): A chromosomal anomaly in which men have two X-chromosomes and one Y chromosome. This leads to infertility, gynecomastia (breast augmentation) and other problems.
    • Patau’s Syndrome (Trisomy 13): The chromosomal anomaly in which the individual has three copies of the 13th chromosome instead of two. This leads to severe vices in development and short life expectancy.
    • Edwards syndrome (Trisomy 18): A chromosomal anomaly in which the individual has three copies of the 18th chromosome instead of two. This leads to severe vices in development and short life expectancy.

3. Genetic testing and counseling:

Genetic testing is an analysis of DNA, RNA or chromosomes to detect genetic changes associated with diseases. Genetic counseling is the process of providing information and support to people with genetic diseases or the risk of their development.

  • Types of genetic testing:
    • Prenatal testing: It is carried out during pregnancy to detect genetic diseases in the fetus. Examples: amniocentesis, choriona biopsy, non -invasive prenatal testing (NIPT).
    • Neonatal screening: It is carried out in newborns to detect genetic diseases that can be treated in the early stages.
    • Diagnostic testing: It is carried out to confirm the diagnosis of a genetic disease in a person with symptoms.
    • Presumptomatic testing: It is carried out in people without symptoms to detect genetic diseases that can develop in the future.
    • Testing of carriage: It is carried out to identify people who are carriers of mutations that can be transmitted to their children.
    • Pharmacogenetic testing: It is carried out to determine how a person will respond to certain drugs based on his genetic profile.
    • Testing a predisposition to diseases: It is carried out to assess the risk of developing certain diseases, such as cancer, cardiovascular diseases and diabetes.
  • Genetic counseling goals:
    • Providing information about genetic diseases, their causes, inheritance, symptoms and treatment.
    • Assessment of the risk of developing or transmitting a genetic disease.
    • Discussion of genetic testing options and their results.
    • Provision of support and assistance in making decisions related to a genetic disease.
    • Direction to specialists, such as geneticist doctors, psychologists and social workers.
  • Ethical considerations in genetic testing and counseling:
    • Confidentiality of genetic information.
    • The possibility of discrimination based on genetic information.
    • The right to make a decision to conduct genetic testing and the use of its results.
    • The influence of genetic information on family relations.
    • Ethical aspects of genetic editing.

4. Genetics and prevention of diseases:

Knowing a genetic predisposition to certain diseases can help in developing strategies for the prevention and early detection of these diseases.

  • Personalized medicine: The approach to the treatment and prevention of diseases based on individual genetic, environmental and figurative characteristics of each patient.
  • Genetically sound diets and lifestyle: Accounting for a genetic predisposition in the development of diets and recommendations on lifestyle to reduce the risk of developing certain diseases. For example, people with a genetic predisposition to cardiovascular diseases can be recommended a low cholesterol and saturated fat diet, as well as regular physical exercises.
  • Early detection and screening: Regular examinations and screening for diseases to which a person has a genetic predisposition. For example, women with a genetic predisposition to breast cancer can be recommended to undergo mammography earlier and more often than women without such a predisposition.
  • Pharmacogenomy: The use of genetic information to select the most effective and safe drugs for each patient. For example, genetic testing can help determine how a person will respond to certain antidepressants or anticoagulants.
  • Gene therapy: The method of treating genetic diseases by introducing a normal copy of the damaged gene or modification into the patient’s cells to correct his function.

5. Genetics and treatment of diseases:

Genetics plays an increasingly important role in the development of new methods of treating diseases.

  • Target therapy: The use of drugs that affect specific genetic mutations that cause cancer. For example, drugs that block the effect of EGFR protein are effective for the treatment of lung cancer in people with mutations in the EGFR gene.
  • Immunotherapy: Using the immune system to combat cancer. Some immunotherapeutic drugs work better in people with certain genetic features.
  • Gene therapy: The method of treating genetic diseases by introducing a normal copy of the damaged gene or modification into the patient’s cells to correct his function. Gene therapy showed promising results in the treatment of some rare genetic diseases, such as spinal muscle atrophy (SMA) and hereditary blindness.
  • CRISPR-CAS9: Genes editing technology, which allows scientists to accurately change DNA in cells. CRISPR-CAS9 has a potential for the treatment of a wide range of genetic diseases, but its use is currently limited by ethical and technical considerations.

6. Evolution and human health:

Evolution is a process of changing the genetic structure of organism populations over time. Evolutionary processes can affect human health both positively and negatively.

  • Adaptation: Evolutionary adaptations can protect against diseases. For example, resistance to malaria in people with sickle cell anemia.
  • Genetic drift: Random changes in the frequency of genes in the population can lead to an increase in the frequency of harmful genes.
  • Evolutionary conflict: Conflicts between genes or between the body and the environment can lead to diseases. For example, aging may be the result of an evolutionary conflict between genes that contribute to reproductive success in youth, and genes that affect health in old age.
  • Modern way of life and evolutionary discrepancy: A modern way of life, characterized by an excess of calories, a lack of physical activity and the effects of chemicals, may contradict the genetic adaptation of a person to environmental conditions that existed in the past. This can lead to an increase in the risk of developing diseases such as type 2 diabetes, cardiovascular diseases and obesity.

7. Genetics of populations and health:

Genetics of populations study the genetic diversity in populations and factors that affect this variety. Knowing the genetic structure of populations can be useful for understanding the spread of diseases and developing prevention and treatment strategies.

  • Genetic structure of populations: Differences in the frequency of genes between different populations can be associated with differences in the prevalence of certain diseases. For example, in people of African origin, the frequency of a gene that causes a sickle -cell anemia than in people of European origin.
  • Genetic flow: The transfer of genes between populations can lead to a change in the genetic structure of populations and the spread of genes associated with diseases.
  • The bottle neck and the effect of the founder: Events in which the population is sharply reduced, can lead to a loss of genetic diversity and an increase in the frequency of rare genetic diseases.
  • The role of migration: The migration of the population to new regions can change the genetic structure of the hosts and spread genes associated with diseases to new regions.

8. Epigenetics and health:

Epigenetics is a study of changes in genes expression that are not associated with changes in the DNA sequence. Epigenetic changes can affect human health and pass from generation to generation.

  • Mechanisms of epigenetics: Epigenetics mechanisms include DNA methylation, histone modification and microrm regulation.
  • The influence of epigenetics on health: Epigenetic changes can play a role in the development of cancer, cardiovascular diseases, diabetes, mental illness and other diseases.
  • Environmental influence on epigenetics: Environmental factors, such as nutrition, stress and the effect of chemicals, can affect epigenetic changes and, therefore, to human health.
  • Epigenetic inheritance: Epigenetic changes can be transmitted from generation to generation, affecting the health of the offspring.

9. Microbia and human genetics:

Microbia is a set of microorganisms that inhabit the human body. Microbia plays an important role in human health, affecting immunity, metabolism and other processes.

  • The composition of the microbioma: The composition of the microbioma can vary in different people and depends on the genetic factors, diet, lifestyle and other factors.
  • The effect of microbioma on health: Microbia can affect the development of diseases such as obesity, diabetes, inflammatory intestinal diseases, autoimmune diseases and mental illness.
  • The interaction of the human microbioma and genetics: Human genetics can affect the composition of a microbioma, and with a microbia can affect the expression of human genes.
  • Modulation of a microbioma to improve health: Modulation of a microbioma using a diet, probiotics, prebiotics or transplantation of fecal microbiota can be an effective method of treating certain diseases.

10. The future of humanity and human health:

Genetics continues to develop rapidly, and in the future further progress is expected in understanding the genetic basis of diseases and the development of new methods of treatment.

  • Big data genomics: Analysis of the large volumes of genetic data to detect genes related to diseases, and develop new treatment methods.
  • Artificial intelligence and genetics: The use of artificial intelligence to analyze genetic data, predicting the risk of developing diseases and developing new drugs.
  • Genes editing: Further development of genes editing technologies, such as CRISPR-CAS9, for the treatment of genetic diseases.
  • Personalized medicine: The wide implementation of personalized medicine based on individual genetic, environmental and figurative characteristics of each patient.
  • Ethical and social issues: The need to solve ethical and social issues related to genetic testing, editing genes and personalized medicine.

In conclusion, genetics plays a key role in determining human health. Understanding the genetic basis of diseases allows you to develop strategies for the prevention, early detection and treatment of diseases. Further progress in genetics promises to improve the health and quality of life of people around the world.

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