Humanity and human health: inextricable connection

Humanity and human health: inextricable connection

I. Fundamentals of genetics and its effect on health

Genetics, the science of heredity and variability, is the basis of understanding of human health. She studies genes, units of hereditary information that are transmitted from parents to offspring and determine the physical and physiological characteristics of the body. Genes carry instructions for the synthesis of proteins that perform many functions necessary for life, including cell construction, transportation of molecules, catalysis of chemical reactions and immune protection. Any changes or mutations in genes can disrupt these functions and lead to the development of diseases.

A. Human genome: a map of heredity

The human genome is a complete set of genetic information contained in DNA (deoxyribonucleic acid). It consists of approximately 3 billion pairs of bases organized in 23 pairs of chromosomes located in the nucleus of each cell. The genome contains about 20,000-25,000 genes encoding proteins, as well as extensive areas of non-dodging DNA, which play an important role in the regulation of genes expression and maintaining the stability of the genome.

The decoding of the human genome in the framework of the “Human Gene” project, completed in 2003, became a revolutionary event in medicine. It has discovered new opportunities for studying the genetic foundations of diseases, developing new methods of diagnosis and treatment, as well as for personalized medicine, taking into account the individual genetic characteristics of each person.

B. Inheritance mechanisms: from parents to offspring

The inheritance of genetic information occurs during sexual reproduction, when the father of the father fertilizes the egg eggs. Each parent conveys half of his genetic material to offspring. As a result of fertilization, a zygote is formed, which contains a full set of chromosomes inherited from both parents.

There are various types of inheritance that determine how genetic features are transmitted from parents to children. The most common are:

1. Autosomal dominant inheritance: To manifest the sign, it is enough to have one copy of the mutant gene on an autosome (non -deciduous chromosome). A patient with a probability of 50% will transmit a mutant gene to each child. Examples of diseases: Huntington disease, neurofibromatosis.

2. Autosomal recessive inheritance: The sign is manifested only if a person inherited two copies of the mutant gene from both parents. If both parents are carriers of the mutant gene, the probability of the birth of a sick child is 25%, the probability of the birth of a healthy carrier is 50%, the probability of the birth of a healthy child is 25%. Examples of diseases: cystic fibrosis, phenylketonuria.

3. X-linked dominant inheritance: The mutant gene is located on the X chromosome. Women who have one copy of the mutant gene usually show signs of the disease, albeit less pronounced than men who have only one X chromosome. The sick father passes the mutant gene to all his daughters and none of the sons.

4. X-linked recessive inheritance: The mutant gene is located on the X chromosome. Women with one copy of the mutant gene are usually carriers and do not show signs of the disease. Men who inherited the mutant gene from the mother show signs of the disease. The sick father does not convey the mutant gene to his sons, but passes it to all his daughters, who become carriers. Examples of diseases: hemophilia, colortonism.

5. Mitochondrial inheritance: Mitochondria, cells of the cell, have their own DNA. Mitochondrial diseases are transmitted only from mother to children, since the sperm does not bring mitochondria to the zygote. All children of a sick mother inherit mutant mitochondria, but the degree of manifestation of the disease can vary depending on the number of mutant mitochondria in cells.

C. Mutations: Sources of genetic variability and disease

Mutations are changes in the DNA sequence that can occur spontaneously or under the influence of external factors, such as radiation, chemicals or viruses. Mutations can be useful, neutral or harmful. Harmful mutations can lead to impaired genes and the development of diseases.

There are various types of mutations, including:

1. Particular mutations: Changes in one pair of DNA bases. They can be replaced (one pair of bases is replaced by another), inserts (one or more pairs of bases are added) or deeds (one or more pairs of bases is removed).

2. Chromosomal mutations: Changes in the structure or quantity of chromosomes. They can be deeds (removal of part of the chromosome), duplications (repetition of part of the chromosome), inversions (coup on the chromosome of 180 degrees) or translocations (transfer of the chromosome section to another chromosome).

3. Genomic mutations: Changes in the amount of chromosomes. They can be aneuploidias (an increase or decrease in the amount of chromosomes) or polyploidias (an increase in the number of sets of chromosomes).

Mutations can occur in germ cells (gametes) or in somatic cells. Mutations in gametes are transmitted to offspring and can cause hereditary diseases. Mutations in somatic cells are not transmitted to offspring, but can lead to the development of cancer or other diseases in this individual.

II. Hereditary diseases: classification and examples

Hereditary diseases are diseases caused by genetic disorders that are transmitted from parents to children. They can be caused by mutations in one gene (monogenic diseases) or in several genes (polygenic diseases), as well as chromosomal or genomic mutations.

A. Monogenic diseases: the influence of one gene

Monogenic diseases are caused by mutations in one gene. They are usually inherited according to the laws of Mendel and can be autosomal-dominant, autosomal-recessive, X-combined dominant or X-combined recessive.

1. MukoviScidoz: Autosomal recessive disease caused by a mutation in the CFTR gene, encoding protein, which regulates the transport of chloride through cell membranes. Violation of the function of this protein leads to the formation of thick mucus, which affects the lungs, pancreas, intestines and other organs.

2. Phenylketonuria: An autosomal recessive disease caused by a mutation in the PAH gene encoding the enzyme phenylaneineinexylase, which is necessary to split the phenylalanine amino acid. The accumulation of phenylalanine in the body leads to damage to the brain and mental retardation.

3. Huntington disease: Autosomal dominant disease caused by a mutation in the HTT gene encoding the Hunting protein. The mutation leads to the formation of an abnormal protein, which accumulates in the brain and causes a progressive violation of motor functions, cognitive abilities and mental health.

4. Sickle -cell anemia: Autosomal recessive disease caused by a mutation in the HBB gene encoding beta-globin, one of the components of hemoglobin. The mutation leads to the formation of abnormal hemoglobin, which causes the deformation of red blood cells in a sickle form. Cherpate red blood cells are less flexible and can block blood vessels, causing pain, organs damage and other complications.

5. Hemophilia: X-linked recessive disease caused by a mutation in genes encoding blood coagulation factors VIII (hemophilia a) or IX (hemophilia b). The mutation leads to a violation of blood coagulation and an increased tendency to bleeding.

B. Polygenic diseases: the influence of several genes and the environment

Polygenic diseases are caused by mutations in several genes, as well as environmental factors. They are not inherited according to the laws of Mendel and have a more complex genetic basis than monogenic diseases.

1. Cardiovascular diseases: Include coronary heart disease, stroke, hypertension and other diseases. The development of cardiovascular diseases depends on the many genetic factors associated with the exchange of cholesterol, blood pressure, blood coagulation and other processes. Environmental factors, such as smoking, malnutrition, lack of physical activity and stress, also play an important role.

2. Type 2 diabetes: It is characterized by a violation of regulation of glucose levels in the blood. The development of diabetes of the 2nd type depends on the many genetic factors associated with sensitivity to insulin, insulin secretion and glucose metabolism. Environmental factors, such as obesity, improper nutrition and lack of physical activity, also play an important role.

3. Cancer: A group of diseases characterized by uncontrolled growth and spread of abnormal cells. The development of cancer depends on the many genetic factors associated with the regulation of the cell cycle, apoptosis (programmed cell death) and DNA reparation. Environmental factors, such as smoking, the effect of ultraviolet radiation and chemicals, also play an important role.

4. Schizophrenia: Chronic mental disorder, characterized by a violation of thinking, perception, emotions and behavior. The development of schizophrenia depends on many genetic factors associated with the function of neurotransmitters, brain development and immune system. Environmental factors, such as stress, infections and the use of psychoactive substances, can also play a role.

5. Alzheimer’s disease: A progressive neurodegenerative disease characterized by impaired memory, thinking and behavior. The development of Alzheimer’s disease depends on many genetic factors associated with the formation of amyloid plaques and neurofibrillar balls in the brain. Environmental factors, such as age, head injuries and cardiovascular diseases, can also play a role.

C. Chromosomal and genomic diseases: disorders in the structure and quantity of chromosomes

Chromosomal and genomic diseases are caused by disorders in the structure or quantity of chromosomes. They can lead to serious disorders of development and health.

1. Down Syndrome (Trisomy 21): It is caused by the presence of an additional copy of the 21st chromosome. It is characterized by mental retardation, characteristic features of the face, heart defects and other health problems.

2. Turner syndrome (monosomy x): It is caused by the absence of one X-chromosome in women. It is characterized by low growth, lack of puberty, infertility and other health problems.

3. Klainfelter syndrome (XXY): It is caused by the presence of an additional X chromosome in men. It is characterized by high growth, gynecomastia (breast augmentation), infertility and other health problems.

4. Patau’s Syndrome (Trisomy 13): It is caused by the presence of an additional copy of the 13th chromosome. It is characterized by severe malformations of the brain, heart and other organs leading to early death.

5. Edwards syndrome (Trisomy 18): It is caused by the presence of an additional copy of the 18th chromosome. It is characterized by severe malformations of the brain, heart and other organs leading to early death.

III. Genetic counseling and diagnostics: Risk assessment and family planning opportunities

Genetic counseling is a process in which genetics specialists provide information and support to people and families with the risk of hereditary diseases. Genetic counseling includes risk assessment, discussion of diagnostic and treatment options, as well as assistance in making decisions related to family planning.

A. Indications for genetic counseling:

• Family history of hereditary diseases.
• The birth of a child with congenital anomalies or mental retardation.
• Repeated miscarriages or infertility.
• Marriage between blood relatives.
• Planning pregnancy by a woman over 35 years old.
• The effect of teratogenic factors during pregnancy.
• The desire to evaluate the risk of developing hereditary diseases.

B. Methods of genetic diagnostics:

1. Family history analysis: Collection of information about the health of family members to identify hereditary diseases and assess risks.

2. Clinical examination: Assessment of the physical condition of a person to identify signs of hereditary diseases.

3. Cytogenetic analysis: The study of chromosomes under a microscope to detect chromosomal abnormalities.

4. Molecular genetic analysis: DNA study to identify mutations in genes. There are various methods of molecular genetic analysis, including:

   • PCR (polymerase chain reaction): The method of amplification (multiplication) of a certain DNA section to facilitate its analysis.
   • DNA sequencing: Determination of the sequence of nucleotides in DNA.
   • DNA microchips: The method of simultaneous analysis of the expression of thousands of genes.
   • Eczu sequencing: Sequencing of only coding areas of the genome (exom).
   • Full -seed sequencing: Sequencing of the entire genome.

5. The prenatal diagnostics: Diagnosis of genetic diseases in the fetus during pregnancy. There are various methods of prenatal diagnosis, including:

   • Amniocentez: Taking a sample of amniotic fluid for the analysis of fetal cells.
   • Chorion Biopsy: Taking a sample of chorion tissue (external shell) for the analysis of fetal cells.
   • Cordocentesis: Taking a blood sample from the fetal umbilical cord for the analysis of fetal cells.
   • Non -invasive prenatal test (NIPT): Analysis of DNA of the fetus circulating in the blood of the mother.

6. Preimplantation genetic diagnostics (PGD): Diagnosis of genetic diseases in embryos obtained as a result of extracurporeal fertilization (IVF), before their implantation into the uterus.

C. Family planning opportunities:

Genetic counseling and diagnostics allow families with the risk of hereditary diseases to make informed decisions on family planning. Possible options include:

• Natural conception: With an assessment of the risks of the birth of a sick child and the possibility of prenatal diagnosis.
• Using donor sperm or eggs: To exclude the risk of transferring the mutant gene from one of the parents.
• Preimplantation genetic diagnostics (PGD): To select healthy embryos for implantation.
• Adoption: To create a family without the risk of transferring hereditary diseases.
• Refusal of childbearing: With a high risk of the birth of a sick child and the absence of other acceptable options.

IV. Genetic predisposition and lifestyle: the interaction of genes and the environment

A genetic predisposition is an increased probability of developing a certain disease due to genetic factors. However, the presence of a genetic predisposition does not mean that the disease will necessarily develop. In most cases, the development of diseases depends on the interaction of genetic factors and environmental factors, including lifestyle.

A. The role of lifestyle in the realization of a genetic predisposition:

1. Nutrition: Proper nutrition can reduce the risk of developing many diseases, even in the presence of a genetic predisposition. For example, the use of a large amount of fruits and vegetables can reduce the risk of cancer, and restriction of salt consumption can reduce the risk of hypertension.

2. Physical activity: Regular physical activity can reduce the risk of developing cardiovascular diseases, type 2 diabetes and certain types of cancer, even in the presence of a genetic predisposition.

3. Smoking: Smoking increases the risk of developing many diseases, especially cancer of the lungs, cardiovascular diseases and chronic obstructive lung disease (hobble). Refusal of smoking can significantly reduce the risk of developing these diseases, even in the presence of a genetic predisposition.

4. Alcohol consumption: Excessive alcohol consumption increases the risk of developing liver diseases, cardiovascular diseases and certain types of cancer. Moderate drinking of alcohol can be safe for some people, but people with a genetic predisposition to alcoholism should avoid alcohol.

5. Stress: Chronic stress can increase the risk of developing cardiovascular diseases, depression and other diseases. Stress management using relaxation techniques, meditation or physical activity can reduce the risk of developing these diseases.

B. Epigenetics: the influence of the environment on the expression of genes

Epigenetics is a study of changes in genes expression that are not associated with changes in the DNA sequence. Epigenetic changes can be caused by environmental factors, such as nutrition, stress and the effect of chemicals. They can affect the development of diseases and be passed on from generation to generation.

Epigenetic mechanisms include:

1. DNA methylation: The connection of the methyl group to DNA, which can suppress the expression of genes.

2. Modification of histones: Changes in the structure of histones, proteins around which DNA are wrapped, which can affect the expression of genes.

3. Regulatory RNA: RNA molecules that can regulate genes expression.

Epigenetics shows that environmental factors can have a long -term effect on human health, even if they do not cause mutations in DNA. This emphasizes the importance of a healthy lifestyle for the prevention of diseases.

V. General therapy: Prospects for the treatment of hereditary diseases

Gene therapy is a method of treating hereditary diseases, which consists in introducing genetic material to the patient’s cells to correct or compensate for a genetic defect. Gene therapy can be directed at:

• Introduction of a normal copy of the gene: To compensate for protein deficiency caused by a mutation in the gene.
• Inactivation of the mutant gene: To prevent the formation of an abnormal protein that causes the disease.
• The introduction of a gene encoding therapeutic protein: For the treatment of a disease that is not associated with a genetic defect, but can be cured using a certain protein.

A. Methods of genetic therapy:

1. Viral vectors: The use of modified viruses for the delivery of genetic material to the patient’s cells. Viruses are effective means of delivery of genetic material, but they can cause an immune reaction or insert genetic material into unwanted places in the genome.

2. Nevirus vectors: The use of liposa (fat bubbles) or other synthetic molecules to deliver genetic material to the patient’s cells. Nevirus vectors are less effective than viral vectors, but they are less toxic and do not cause immune reaction.

3. CRISPR-CAS9 technology: The genome editing system, which allows you to accurately cut and insert genetic material into certain places in the genome. CRISPR-CAS9 is a promising technology for the treatment of hereditary diseases, but it is still under development and has potential risks.

B. Examples of successful genetic therapy:

• Treatment of spinal muscle atrophy (SMA): The drug Zolgensma, based on genetic therapy, allows you to introduce a normal copy of the SMN1 gene, the deficiency of which causes SM, into the patient’s cells.
• Treatment Amaurosis Lever: The drug Luxturna, based on genetic therapy, allows you to introduce a normal copy of the RPE65 gene, the deficiency of which causes Leber Amaurosis, into the cells of the retina.
• Treatment of beta-Talassemia: The drug Zynteglo, based on genetic therapy, allows you to introduce a modified copy of the beta-globin gene, the deficiency of which causes beta-Talassemia, into the patient’s bone marrow cells.

C. Ethical and social issues of genetic therapy:

Gene therapy raises important ethical and social issues, such as:

• General therapy safety: It is necessary to make sure that gene therapy is safe for patients and does not cause undesirable side effects.
• Accessibility of genetic therapy: It is necessary to ensure the availability of genetic therapy for all in need of patients, regardless of their social status and place of residence.
• Editing the embryo line: Editing the genome of germ cells (gametes) or embryos can lead to the transfer of genetic changes to future generations. This practice causes serious ethical fears and requires careful regulation.
• Human improvement: Gene therapy can be used not only for the treatment of diseases, but also to improve the physical or mental abilities of a person. This practice also causes ethical fears and requires discussion.

VI. Conclusion:

Heredity plays a fundamental role in determining human health. Understanding the genetic foundations of diseases, mechanisms of inheritance and interaction of genes and the environment allows you to develop new methods of diagnosis, treatment and prevention of diseases. Genetic counseling and diagnostics help families with the risk of hereditary diseases to make informed decisions on family planning. Gene therapy opens up new prospects for the treatment of hereditary diseases. However, it is necessary to take into account ethical and social issues related to genetic technologies and ensure their responsible use. The development of genetics and genomes will continue to have a deep effect on medicine and healthcare in the future.