Introduction
Asthma is a chronic respiratory disorder that occurs as a result of interaction between genetic and environmental elements. Despite not being entirely comprehended, research has emphasized the substantial influence of genetics on asthma development. Asthma tends to have a hereditary pattern, and children who have asthmatic parents have a high risk of acquiring asthma. The emergence of advanced genotyping has led to sequencing human genomes, and there has been a surge in the identification of common and rare genetic variants associated with asthma.
What Is Asthma?
Asthma is a respiratory condition in which there is inflammation of the airways and recurrent episodes of breathing difficulties called asthma attacks. A common type of asthma is allergic asthma which eventuates due to the reaction of the immune system to potential allergens like hay, pollen, and dust, even if they are harmless, causing airway inflammation. The key feature of asthma is bronchial hyperresponsiveness, in which the airways are highly sensitive to irritants. This can result in attacks triggered by other factors such as respiratory infection, physical activity, and smoke exposure, especially in individuals having allergic asthma.
How Is Genetics Related to Asthma?
Asthma is a complex disease that is substantially influenced by genetics. Asthma can occur as a result of an interplay between genetic variations and environmental factors. Research has paved the way for understanding the genetics of asthma. Here is an overview of the genetic aspect of the disease asthma:
1. Heritability: Asthma tends to run in families, indicating a hereditary component in this condition. The inheritance pattern of asthma is not straightforward due to its polygenic nature (influenced by multiple genes).
2. Polygenic Nature: Asthma is considered a polygenic disease that occurs as a result of interaction between multiple genes, each contributing to overall risk in varying degrees. Numerous genes associated with asthma influence the body in various aspects, such as airway remodeling, inflammation, and immune response.
3. Candidate Gene: Extensive research has been done on candidate genes and their involvement in causing asthma, which includes the following:
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ADAM33: This gene has an important role in airway remodeling, which is a characteristic feature of asthma. ADAM33 gene variations have been associated with an increased risk of asthma.
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Beta-2 Adrenergic Receptor (ADRB2): Genetic variations in ADRB2 have an impact on bronchodilation. They are also associated with asthma and the response to asthma medications.
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Interleukins (IL): Certain types of interleukins like IL-13, IL-4, and IL-17 regulate the immune system. Asthma susceptibility increases if there are genetic variations.
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ORMDL3-GSDMB: Variations in this gene locus are linked to childhood-onset asthma and airway hyperresponsiveness.
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Filaggrin: Filaggrin is a gene that is involved in maintaining skin barriers. Filaggrin mutations have been associated with hay fever, allergic sensitization, and asthma, primarily in individuals affected by atopic dermatitis.
4. Genome-Wide Association Studies: GWAS have been extensively contributing to the identification of additional genetic factors linked with asthma risk. These studies evaluate the genomes of a large set of people to identify the common genetic variations that are more prevalent in asthma-affected individuals.
5. Gene-Environment Interactions: Asthma risk is not solely determined by genetics. There is a crucial role in gene-environment interactions too. Environmental factors including air pollution, allergens, smoking, respiratory infections, smoking, and lifestyle choices, can interact with an individual’s genetic makeup causing asthma development. Unraveling the mechanisms which control and express these genes may be the key to understanding the intricate interplay between environmental factors and genetics in the onset and advancement of allergies and asthma.
6. Epigenetics: Epigenetics investigates heritable changes in disease that do not result from alterations in the genetic code’s nucleotide sequence. Epigenetic modifications can also impact asthma development. These changes can modify gene expression without any change to the underlying DNA (deoxyribonucleic acid) sequence. Environmental factors can induce epigenetic changes that affect the activity of genes related to asthma. Both epigenetic and genetic alterations can contribute to asthma susceptibility.
7. Linkage Studies: Linkage studies are specifically formulated to accurately pinpoint genetic markers associated with asthma through statistical association. These studies are highly efficient in the identification of chromosomal regions that exhibit a connection between asthma and new genetic factors. Once such regions are identified, fine genotype mapping is used to precisely identify the actual gene or genes responsible.
What Is the Role of Pharmacogenetics and Personalized Medicine in Asthma Management?
In this post-genomic era, personalized medicine has emerged as a growing and important field. Its central establishment is the utilization of genetic information for predicting which patients will best respond to specific treatments. As this field advances, pharmacotherapy can be tailored to each individual based on their unique genetic makeup.
In such a way, any adverse effects that can occur as a result of certain drugs can be preserved, and only the patients compatible with that drug can be treated. This will help in avoiding potentially harmful effects in those who may be susceptible to adverse reactions and toxicity. Genes encoding receptor proteins that take part in an active role in drug transportation, processing, degradation, and excretion are key areas of focus. Ongoing research into the biological pathways connected to asthma and allergies holds promise in identifying potential targets for intervention.
What Is the Future of Asthma Genetics?
Molecular genetics research and studies in asthma have been significantly advanced, leading to a better understanding of the disease and its progression. There have been no groundbreaking discoveries in terms of treatment modification and innovative treatments. It has become evident that asthma is influenced by a multitude of genes, with each gene contributing a minor amount to the overall risk of asthma development. Genome-wide association studies and deep sequencing studies confirmed the immense diversity of asthma, both phenotypically and genetically. The genetic composition of individuals with asthma varies significantly, adding to the intricate nature of this disease.
Conclusion
In conclusion, asthma is a multifaceted condition influenced by both genetic and environmental components. A family history of asthma points to a strong genetic component, with certain genes making individuals more susceptible to asthma triggered by environmental factors. However, some genes can directly contribute to early onset or severe types of asthma, frequently running in families. In essence, asthma arises from a complex interplay between genetic and environmental factors, where genetics is just one part of a much broader picture.
