Heredity as a risk factor for diseases

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Heredity as a risk factor for diseases: a deep analysis of the genetic predisposition and its effect on health

I. Fundamentals of genetic heredity and its role in health

Genetic heredity, the cornerstone of the biological transmission of signs from generation to generation, plays a decisive role in determining the susceptibility of a person to various diseases. This transmission is carried out through deoxyribonucleic acid (DNA), a complex molecule containing genetic instructions necessary for the development, functioning and reproduction of all known living organisms and many viruses. DNA is organized in chromosomes, and each person usually inherits 23 chromosomes from each parent, forming a couple of 46 chromosomes.

A. GENS: Construction blocks of heredity

Genes, the main units of heredity, are DNA segments that contain instructions for the synthesis of certain proteins. These proteins perform a wide range of functions in the body, including catalysis of biochemical reactions, transportation of molecules and ensuring structural support. Differences in the sequence of DNA genes, known as alleles, can lead to differences in the structure and functions of proteins, which, in turn, affects the phenotype, the observed characteristics of the body.

B. mutations: a source of genetic variability and disease

Mutations, changes in the sequence of DNA, are the main source of genetic variability. Although many mutations are neutral or even useful, some can be harmful and increase the risk of diseases. Mutations can occur spontaneously in the process of DNA replication or be caused by the influence of environmental factors, such as radiation or chemicals.

B. Types of inheritance: how genetic diseases are transmitted

Genetic diseases can be transmitted differently, depending on the type of gene involved in the disease, and its localization on the chromosome. The main types of inheritance include:

  1. Autosomal dominant inheritance: The disease manifests itself when a person inherits only one copy of the mutant gene from one of the parents. Each child of a person suffering from an autosomal dominant disease has a 50% chance to inherit a mutant gene and disease. Examples: Gentington disease, neurofibromatosis.

  2. Autosomal recessive inheritance: The disease manifests itself when a person inherits two copies of a mutant gene, one from each parent. The parents of a person suffering from an autosomal recessive disease are usually carriers, that is, they have one copy of the mutant gene, but they do not show signs of the disease. Each child of two carriers has a 25% chance to inherit both copies of the mutant gene and get sick, a 50% chance to be a carrier and a 25% chance not to inherit a mutant gene. Examples: cystic fibrosis, phenylketonuria, sickle cell anemia.

  3. X-linked dominant inheritance: The disease is manifested in women who have one copy of the mutant gene on the X chromosome, and in men who have one copy of the mutant gene on their only X chromosome. Women with one copy of the mutant gene can have more mild symptoms than men. Each child of a woman with x-linked dominant disease has a 50% chance to inherit a mutant gene. Every son of a man with a X-linked dominant disease will not inherit a mutant gene, but each daughter will inherit a mutant gene. Examples: Vitamin-D-resistant rickets.

  4. X-linked recessive inheritance: The disease manifests itself mainly in men who have one copy of the mutant gene on their only x chromosome. Women can be carriers of a mutant gene on one of their x chromosomes, but usually do not show signs of the disease, since they have a second, normal X chromosome. Each son of a ladder woman has a 50% chance to inherit a mutant gene and get sick. Each daughter of a ladder woman has a 50% chance to become a carrier. Men with X-linked recessive disease do not convey the disease to their sons, but all their daughters will be carriers. Examples: hemophilia, colortonism.

  5. Mitochondrial inheritance: Mitochondria, organelles in cells that produce energy have their own DNA. Mitochondrial diseases are transmitted only from the mother, since spermatozoa does not bring mitochondria into a fertilized egg. All children of the mother with mitochondrial disease inherit mutant mitochondrial DNA, but the severity of the disease can vary. Examples: Leia syndrome, MELAS syndrome.

II. Genetic predisposition to common diseases

Many common diseases, such as cardiovascular diseases, diabetes, cancer and mental disorders, are the result of complex interaction between genetic factors and environmental factors. Although specific genes involved in these diseases may vary, genetic predisposition plays a significant role in determining individual risk.

A. cardiovascular diseases

  1. Hypertension (high blood pressure): Family history of hypertension significantly increases the risk of developing this disease. Genes affecting the regulation of blood pressure, the function of the kidneys and sodium metabolism can contribute to the development of hypertension.

  2. Corny heart (coronary heart disease): Genetic factors affecting the level of cholesterol, inflammation and coagulation of blood can increase the risk of IBS. Certain genes, such as LDLR, APOB And PCSK9associated with an increased level of LDL cholesterol (“bad” cholesterol) and an increased risk of coronary heart disease.

  3. Stroke: A genetic predisposition to stroke can be associated with genes that affect blood pressure, blood coagulation and the structure of blood vessels.

B. Diabetes

  1. Type 1 diabetes: Type 1 diabetes is an autoimmune disease in which the body’s immune system attacks and destroys insulin-producing cells in the pancreas. Genes HLA They play an important role in determining the risk of developing diabetes of the 1st type.

  2. Type 2 diabetes: Type 2 diabetes is characterized by insulin resistance and insulin deficiency. Genetic factors affecting the function of the pancreatic beta cells, insulin sensitivity and glucose metabolism can contribute to the development of type 2 diabetes. Many genes such as TCF7L2, PPARG And KCNJ11associated with an increased risk of type 2 diabetes.

V. Cancer

Many types of cancer have a genetic component. Genetic mutations can either directly cause cancer, or increase susceptibility to carcinogenic environmental factors.

  1. Breast cancer: Genes Krca1 And BRCA2 are the most famous genes associated with an increased risk of developing breast cancer and ovarian cancer. Mutations in these genes violate the ability of the cell to restore damaged DNA, which leads to increased risk of cancer.

  2. Tolstoy Cancer: Family adenomatous polyposis (SAP) is a hereditary disease, which is characterized by the development of multiple polyps in the colon. Mutations in gene APC are the cause of the CAP and significantly increase the risk of developing colon cancer.

  3. Prostate cancer: Family history of prostate cancer significantly increases the risk of developing this disease. Some genes such as HPC1, Rnasel And ELAC2associated with an increased risk of developing prostate cancer.

G. Mental disorders

Mental disorders, such as schizophrenia, bipolar disorder and depression, have a complex etiology in which genetic factors play a significant role.

  1. Schizophrenia: Family research and twin studies have shown that schizophrenia has a high degree of inheritance. Many genes such as Disc1, DTNBP1 And Wrg1associated with an increased risk of development of schizophrenia.

  2. Bipolar disorder: Bipolar disorder is characterized by episodes of mania and depression. Genetic factors affecting the function of neurotransmitters and mood regulation can contribute to the development of bipolar disorder.

  3. Depression: Depression is a common mental disorder, which is characterized by a constant feeling of sadness and loss of interest in activity. Genetic factors affecting the function of serotonin and other neurotransmitters can contribute to the development of depression.

III. Genetic testing and counseling: tools for evaluating and managing genetic risk

Genetic testing and counseling have become valuable tools for assessing individual genetic risk of developing diseases and making justified decisions on the prevention, treatment and planning of the family.

A. types of genetic testing

  1. Diagnostic testing: It is used to confirm or exclude the diagnosis of a genetic disease in a person, which shows signs or symptoms of the disease.

  2. Predictive testing: It is used to determine the risk of developing a genetic disease in the future in a person who has no signs or symptoms of the disease.

  3. Testing of carriage: It is used to determine whether a person is a carrier of a mutant gene that can be transferred to his children.

  4. Prenatal testing: Used to diagnose genetic diseases in the fetus during pregnancy.

  5. Preimplantation genetic diagnostics (PGD): It is used to diagnose genetic diseases in embryos created using extorporepical fertilization (IVF) before implantation into the uterus.

B. Genetic counseling

Genetic counseling is a process that includes an assessment of a family history, discussing the risks and advantages of genetic testing, interpretation of genetic testing and providing support and information to make reasonable decisions. Genetic consultants are medical specialists who are trained to help people and families understand and cope with genetic risks.

B. Ethical considerations

Genetic testing and counseling raise important ethical considerations, such as confidentiality, discrimination and use of genetic information for eugenic purposes. It is important that genetic testing is carried out responsibly and with respect to autonomy and personality rights.

IV. The influence of the lifestyle and the environment on the genetic predisposition

Although a genetic predisposition plays an important role in determining the risk of developing diseases, the factors of the lifestyle and the environment also have a significant impact. A healthy lifestyle and the avoidance of harmful environmental influences can reduce the risk of diseases even in people with a high genetic predisposition.

A. Life Life Factors

  1. Diet: A healthy diet rich in fruits, vegetables and whole cereals can reduce the risk of developing many diseases, including cardiovascular diseases, diabetes and cancer.

  2. Physical activity: Regular physical activity can improve cardiovascular health, control blood sugar and reduce the risk of cancer.

  3. Smoking: Smoking is the main risk factor for the development of many diseases, including lung cancer, cardiovascular disease and chronic obstructive lung disease (COPD).

  4. Alcohol consumption: Excessive drinking of alcohol can increase the risk of developing liver diseases, cardiovascular diseases and certain types of cancer.

B. Environmental factors

  1. Air pollution: The effect of contaminated air can increase the risk of respiratory diseases, cardiovascular diseases and cancer.

  2. Radiation: The impact of radiation can increase the risk of cancer.

  3. Chemicals: The effect of certain chemicals can increase the risk of cancer and other diseases.

V. New areas in genetic research and therapy

The area of ​​genetics is developing rapidly, and new discoveries promise to improve the understanding of a genetic predisposition to diseases and develop new treatment methods.

A. Genomic studies

Genomic studies, such as a full -genomic search for associations (GWAS), are used to identify genetic options associated with an increased risk of developing diseases. These studies can help identify new goals for prevention and treatment.

B. editing genes

Genes editing, such as CRISPR-CAS9, is a powerful technology that allows scientists to accurately change the DNA sequence. Genes can be used to correct mutant genes that cause diseases.

B. Gene therapy

Gene therapy includes the introduction of genetic material into human cells to treat diseases. Gene therapy can be used to replace mutant genes, the introduction of new genes or inactivation of harmful genes.

G. Personalized medicine

Personalized medicine uses human genetic information to develop individual treatment plans. This approach can lead to more effective and safe treatment methods.

VI. Conclusion (absent, according to the instructions)

VII. List of literature (not included, since there are no requirements in the task)

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