Genetic predisposition to allergies: the role of heredity
I. Introduction to allergies and its prevalence
Allergies are an abnormal immune reaction of the body to usually harmless substances called allergens. These substances can be anything from the pollen of plants and foods to the poison of insects and drugs. When an allergen enters the human body with a genetic predisposition, the immune system mistakenly identifies it as a threat and begins to produce antibodies called E (Ige) immunoglobulins. These antibodies are associated with fat cells and basophils, which release histamine and other inflammation mediators when re -contact with the allergen, causing various allergic symptoms.
The prevalence of allergic diseases has increased significantly over the past decades, which makes them one of the most common chronic health problems around the world. According to the World Health Organization (WHO), hundreds of millions of people suffer from allergic diseases. Allergy affects people of all ages, races and socio-economic groups, but most often occurs in children and young people. In developed countries, the prevalence of allergies is especially high.
Various types of allergies include:
- Allergic rhinitis (hay fever): It is caused by allergens, transferred through the air, such as pollen, mold and animal hair. Symptoms include a runny nose, sneezing, itching in the nose and eyes.
- Asthma: Chronic inflammatory disease of the respiratory tract, often caused by allergens. Symptoms include wheezing, coughing, constraint in the chest and shortness of breath. Allergic asthma is the most common type of asthma.
- Food allergies: It is caused by certain foods such as peanuts, wood nuts, milk, eggs, soy, wheat, fish and mollusks. Symptoms can vary from the lungs (urticaria, itching) to severe (anaphylaxia).
- Medicine allergies: It is caused by certain drugs, such as penicillin and other antibiotics. Symptoms can vary from rash and itching to anaphylaxia.
- Allergies to insect poison: It is caused by bite or stinging of insects, such as bees, wasps and ants. Symptoms can vary from local reactions (edema, redness) to anaphylaxia.
- Contact dermatitis: It is caused by contact with certain substances, such as poisonous ivy, nickel and latex. Symptoms include a rash, itching and blisters.
- Atopic dermatitis (eczema): Chronic inflammatory skin disease, often associated with allergies. Symptoms include itching, dryness and redness of the skin.
The severity of allergic reactions can vary from lungs to life -threatening. Anaphilaxia is a severe, potentially deadly allergic reaction that can cause difficulty breathing, reducing blood pressure and loss of consciousness. Anaphilaxia requires immediate medical care, including epinephrine injection (adrenaline).
II. The role of heredity in the development of allergies
A genetic predisposition plays a significant role in the development of allergies. Children whose parents suffer from allergies are more likely to also suffer from allergies. However, it is important to note that the presence of a genetic predisposition does not mean that a person will necessarily develop allergies. The development of allergies is a complex process, which is affected by both genetic and environmental factors.
Heredity for allergies is not a transmission of a specific allergy, but a transmission of a tendency to the development of allergic reactions in general. This is called atopia. Atopia is a genetic predisposition to the production of IgE antibodies in response to ordinary environmental allergens. People with atopia have a higher risk of allergic rhinitis, asthma, eczema and food allergies.
Studies have shown that the risk of developing allergies increases if one or both parents suffer from allergies:
- If one parent suffers from allergies, the risk of developing allergies in a child is approximately 30-40%.
- If both parents suffer from allergies, the risk of developing allergies in a child is approximately 60-80%.
However, even if none of the parents suffers from allergies, the child can still develop allergies, since genetic factors are not the only determining factor.
III. Allergies
Numerous genes were identified as related to the development of allergies. These genes participate in various aspects of the immune system, including:
- Regulation of the immune response: Genes that control the activation and regulation of immune cells, such as T cells and B cells, play an important role in the development of allergies.
- Ige development: Genes participating in the production of IgE antibodies can affect the strength of an allergic reaction.
- Function of the barrier of the skin and mucous membranes: Genes affecting the structure and function of the skin and mucous membranes can affect the penetration of allergens into the body.
- Inflammatory processes: Genes involved in inflammatory processes can affect the severity of allergic symptoms.
Some of the most studied genes associated with allergies include:
- IL-4, IL-5, IL-13: These genes encode cytokines that play an important role in the production of IgE and the development of allergic inflammation. Variations in these genes are associated with an increased risk of development of asthma, allergic rhinitis and eczema.
- FCER1A: This gene encodes the alpha-to-the-clod of the IgE receptor with high affinity, which is located on the surface of fat cells and basophils. Variations in this gene can affect the ability of Ige to contact these cells and cause the release of inflammation mediators.
- HLA (Human Leukocyte Antigen): HLA genes participate in the presentation of antigens to T-cells and play an important role in the regulation of the immune response. Certain HLA alleles are associated with an increased risk of allergies.
- Filaggrin (FLG): This gene encodes a protein that plays an important role in maintaining the barrier function of the skin. Mutations in the FLG gene are the main risk factor for the development of atopic dermatitis.
- SPINK5: This gene is encoded by an inhibitor of serinal protease, which plays a role in the regulation of inflammatory processes in the skin. Mutations in the Spink5 gene are associated with the syndrome of Neterton, a severe skin disease, which is often accompanied by allergies.
- Adam33: This gene is associated with the development of asthma and bronchial hyperreactivity. It is involved in remodeling of the respiratory tract, which is a characteristic feature of asthma.
- PHF12: This gene was identified as a risk factor for the development of food allergies, especially the allergies to peanuts.
- LRRC32: This gene plays a role in the activation of TGF-β, cytokine, which is important to regulate the immune response and maintain immune tolerance. Variations in this are related to an increased risk of allergies.
- Stat6: This gene encodes the transcription factor, which is involved in the transmission of the IL-4 and IL-13 signals, key cytokines in the development of allergies. Variations in this are related to an increased risk of developing asthma and atopic dermatitis.
- GRWR2: This gene plays a role in maintaining the barrier function of the skin. Variations in this are related to an increased risk of developing atopic dermatitis.
It is important to emphasize that most allergies are polygenic, that is, they are caused by the interaction of several genes, and not one gene. Moreover, the interaction of genes with environmental factors also plays an important role in the development of allergies.
IV. Interaction of genes and the environment
Although a genetic predisposition is an important risk factor for the development of allergies, environmental factors also play an important role. The interaction between genes and the environment determines whether a person will develop an allergy and how severe his allergies will be.
Some of the most important environmental factors affecting the development of allergies include:
- The effect of allergens: The early and frequent effects of allergens, such as pollen, animal hair and food, can increase the risk of allergies, especially in people with a genetic predisposition.
- The effect of tobacco smoke: The effect of tobacco smoke, especially in childhood, is associated with an increased risk of developing asthma and other allergic diseases.
- Air pollution: Air pollution, especially with hard particles and ozone, can aggravate allergic symptoms and increase the risk of allergies.
- Infections: Some infections, especially respiratory viral infections in early childhood, can increase the risk of asthma and other allergic diseases. However, some infections, especially parasitic infections, can have a protective effect against allergies. Hygiene hypothesis suggests that a decrease in the effects of infections in early childhood can lead to increased risk of allergies due to insufficient stimulation of the immune system.
- Intestinal microbia: The intestinal microbia, that is, the community of microorganisms living in the intestines, plays an important role in the development of the immune system and can affect the risk of allergies. The variety and composition of the intestinal microbioma can affect the development of allergic diseases. In the intestinal microbia, factors such as diet, the method of delivery (natural birth or cesarean section) and the use of antibiotics can affect.
- Diet: Diet can affect the risk of allergies both directly (through the effects of food allergens) and indirectly (through the effect on the intestinal microbia and the immune system). Some studies show that eating products rich in antioxidants and anti -inflammatory compounds can reduce the risk of allergies.
- Vitamin D: The low level of vitamin D in the blood is associated with an increased risk of allergies, especially asthma. Vitamin D plays an important role in the regulation of the immune system.
- Stress: Chronic stress can weaken the immune system and increase the risk of allergies.
Epigenetic mechanisms also play an important role in the interaction of genes and the environment. Epigenetic changes are changes in genes expression that are not associated with changes in the DNA sequence. Epigenetic changes can be caused by environmental factors and can be transmitted from generation to generation. Epigenetic changes can affect the expression of genes associated with allergies, and thus influence the risk of allergies.
V. Diagnosis and treatment of allergies, taking into account the genetic predisposition
Given the role of heredity in the development of allergies, genetic testing can be useful for identifying people who are at risk of developing allergies. However, genetic testing for allergies is still in the early stages of development and is not widespread in clinical practice. Most genetic tests for allergies assess the presence of certain genetic options associated with an increased risk of allergies. However, it is important to note that the presence of these genetic options does not mean that a person will necessarily develop allergies.
Traditional methods of allergy diagnostics include:
- A history of anamnesis: The doctor asks the patient about his allergic symptoms, the medical history, the family history of allergies and the effects of allergens.
- Skin tests: A small amount of allergen is applied to the skin, and then the skin is slightly pierced or scratched. If a person has an allergy to this allergen, a small itchy blister appears on the skin.
- Blood test for Ige: The level of IgE antibodies to certain allergens in the blood is measured.
The results of genetic testing can be used in combination with traditional methods for diagnosing allergies for a more accurate assessment of the risk of developing allergies in humans.
Treatment of allergies is aimed at alleviating symptoms, preventing allergic reactions and improving the quality of life. The main methods of allergy treatment include:
- Avoiding allergens: The most effective way to prevent allergic reactions is to avoid the effects of allergen allergies. This may require a change in lifestyle, such as regular cleaning of the house, the use of air cleaners, avoiding certain foods or drugs.
- Medicines: To relieve allergic symptoms, various drugs can be used, such as antihistamines, corticosteroids, decongestants and bronchodilators.
- Immunotherapy (allergen-specific immunotherapy): Immunotherapy includes the introduction of small doses of allergen over a long period of time to help the body get used to the allergen and reduce its sensitivity to it. Immunotherapy can be effective for the treatment of allergic rhinitis, asthma and allergies to the poison of insects. It can be carried out in the form of injections (subcutaneous immunotherapy) or sublingual tablets or drops (sublingual immunotherapy).
- Epinephrine (adrenaline): Epinephrine is a medicine used to treat anaphylaxia, severe allergic reaction. People at the risk of anaphilaxia should always have an epinephrine autoinfrine autoinfine and know how to use it.
In the future, the development of personalized medicine will develop methods for treating allergies, taking into account the genetic predisposition of each patient. This may include the use of genetic information to select the most effective drugs and immunotherapy for a particular patient. For example, people with certain genetic options can react better to certain types of immunotherapy.
VI. Allergies prevention in children with a genetic predisposition
Given the role of heredity in the development of allergies, preventive measures can be especially important for children with a genetic predisposition to allergies. Some of the measures that can be taken to reduce the risk of allergies in children include:
- Breast-feeding: Breastfeeding is the best way to feed babies, especially those that have a genetic predisposition to allergies. Breastfeeding helps strengthen the child’s immune system and reduce the risk of allergies. It is recommended exclusively breastfeeding during the first 6 months of life.
- Body introduction: The introduction of complementary foods should be postponed to the age of 6 months. The introduction of new products should be carried out gradually, one at a time so that possible allergic reactions can be identified. Earlier it was believed that a delay in the administration of highly allergenic products, such as peanuts and eggs, can reduce the risk of food allergies. However, recent studies show that the early administration of these products (aged 4-6 months) can actually reduce the risk of food allergies, especially in children with a high risk of allergies (for example, children with eczema or family history of food allergies). It is important to consult a doctor or nutritionist before entering new products into the child’s diet.
- Probiotics: Some studies show that the intake of probiotics during pregnancy and in early childhood can reduce the risk of allergies in children with a genetic predisposition. Probiotics are living microorganisms that are useful for intestinal health.
- The effect of allergens: Avoiding the effects of allergens in early childhood can be useful for reducing the risk of allergies. This may include maintaining cleanliness in the house, using air cleaners and avoiding contact with animal hair.
- Refusal of smoking: Pregnant women and parents should avoid smoking, since the effects of tobacco smoke can increase the risk of allergies in children.
- Vitamin D: A sufficient level of vitamin D in the blood is important for the development of the child’s immune system. The doctor may recommend vitamin D additives for babies and children, especially if they are at risk of developing vitamin D.
It is important to note that the prevention of allergies is a complex process, and there is no single approach that would suit everyone. It is recommended to consult a doctor or an allergist to develop an individual allergy prevention plan for your child.
VII. Ethical and social aspects of genetic testing for allergies
Genetic testing for allergies raises a number of ethical and social issues that must be taken into account.
- Confidentiality: Genetic information is personal and confidential. It is important to ensure that the genetic information of patients is protected from unauthorized access and use.
- Discrimination: There is a risk that genetic information can be used to discriminate against people with a genetic predisposition to allergies, for example, when applying for work or insurance. It is necessary to take measures to prevent genetic discrimination.
- Anxiety and anxiety: The results of genetic testing can cause anxiety and anxiety in patients, especially if they find out that they have a genetic predisposition to allergies. It is important to provide patients with consultations and support to help them cope with the emotional consequences of genetic testing.
- Accessibility: Genetic testing for allergies should be available to everyone who needs it, regardless of their socio-economic status.
- Accuracy and interpretation: It is important to ensure that genetic tests are accurate and reliable, and the results are correctly interpreted. Patients should receive clear and understandable information about the advantages and restrictions of genetic testing.
- Reproductive solutions: Genetic information can affect the reproductive solutions of people, for example, to decide to have children or use auxiliary reproductive technologies. It is important that people make reasonable reproductive decisions based on accurate and complete information.
VIII. Future research areas
Studies in the field of allergy genetics continue to develop. Future studies include:
- Identification of new genes related to allergies: Further research is needed to identify new genes that are involved in the development of allergies. This can help better understand the genetic basis of allergies and develop more effective methods of diagnosis and treatment.
- Studying the interaction of genes and the environment: Further research is needed to study the interaction between genes and environmental factors in the development of allergies. This can help identify risk factors for the development of allergies and develop prevention strategies.
- Development of personalized allergy treatment methods: In the future, the development of personalized medicine will develop methods for treating allergies, taking into account the genetic predisposition of each patient. This may include the use of genetic information to select the most effective drugs and immunotherapy for a particular patient.
- Development of new methods of allergy prevention: Further research is needed to develop new methods of allergies, especially in children with a genetic predisposition. This may include the development of new probiotics, dietary strategies and methods of environmental impact.
- Improving genetic testing for allergies: Further studies are needed to improve the accuracy and reliability of genetic tests for allergies. This may include the development of new genetic tests that evaluate the presence of more genetic options associated with allergies.
- The study of the epigenetic mechanisms of allergies: Further research is needed to understand the role of epigenetic changes in the development of allergies. This can open new opportunities for the prevention and treatment of allergic diseases.
IX. Conclusion (not on the request)
X. List of literature (not on upon request)