Genetics and Asthma - An Overview

Asthma and DNA: How Your DNA Impacts Asthma Risk?

Have you ever asked yourself why some individuals get asthma, and others do not? Is asthma inherited, or is it bad luck? The reality is that your deoxyribonucleic acid (DNA) has a lot to do with whether or not you are at risk. However, genetics is not the only thing—your environment also plays a role. Let's take a look at how your genes and environment influence your asthma risk.

Is Asthma Genetic?

So, is asthma really in your genes? The response is neither a simple yes nor no. In contrast to monogenic conditions (genetic conditions caused by mutations in a single gene), asthma is polygenic, i.e., multiple genes are implicated. Studies on twins and families show that asthma has a hereditary component ranging from 25 to 80 percent. If you have asthma, there is a good chance that a member of your family also has asthma. But genes do not determine your fate entirely—your environment is also an important factor.

How Genetics Influence the Risk of Asthma?

Can You Inherit Asthma From Your Parents?

Yes! The inherited risk of asthma is something to take into account. If your parents do not have asthma, your risk is just 5 %. But if one of them does, that risk increases to 25 %, and if both of them have asthma, your risk goes up even more. In identical twins who have the same DNA, the risk can be as high as 75 %, a good indication that there is a genetic factor at play.

Yet another fascinating fact. Even the age at which you develop asthma has genetic correlations. Asthma occurring early in life (childhood asthma) is more heritable, and adult-onset (late-onset) asthma could be triggered by immune system genes like human leukocyte antigen DQ (HLA-DQ).

What Are the Genes Responsible for Asthma?

Researchers have spotted a number of significant genes associated with asthma development.

They control everything from airway inflammation to immune response and lung function.

The most important genes involved in the development of asthma are:

• (IL1RL1) Gene - Controls immune response and airway inflammation.

• (IL33) Gene - Activates allergic responses and airway inflammation.

• (IL13) Gene - Controls immune system reaction to allergens.

• (ORMDL3) Gene - Highly associated with early-onset asthma, regulates lung inflammation.

• HLA-DQ (A1/B1) - Associated with immune system regulation and late-onset asthma.

Revealing the Genetic Code of Lung Function and Airways Sensitivity

Ever wonder why people have more sensitive airways than others? Perhaps the answer is in their DNA. The key genetic factors that promote lung function are.

1. ADAM33 Gene (A-Disintegrin and Metalloproteinase 33) - It aids in the remodeling of airway muscle.

2. DPP10 (Dipeptidyl Peptidase 10) - This factor helps in the development of lungs.

3. SMAD3 - This factor promotes lung tissue repair and inflammation and also plays an important role in maintaining respiratory resilience.

Your genes may be controlling your breath—get educated and breathe easy!

How Your Body's Barrier Defenses Work Against Asthma?

Asthma is actually affected by barrier function in the skin and lungs, too. If your body is not able to block the allergens, your immune system overreacts:

• Filaggrin (FLG) – Sustains airway and skin barrier function; its mutations are linked with asthma and eczema.

• Serine Peptidase Inhibitor Kazal Type 5 (SPINK5) – Affects the body's defense barriers, influencing allergic reactions.

• Toll-Like Receptors (TLRs 2, 4, 6, 9, 10) – Help to identify potentially harmful substances in the environment and trigger immune responses.

Environmental Factors and Gene-Environment Interactions

How Does the Environment Cause Asthma in Genetically Susceptible Individuals?

Though having genes for asthma, you may not develop symptoms unless something in the environment triggers them. The common triggering factors are:

• Air Pollution - Asthma symptoms can get worse from smoke, car fumes, and industrial chemicals.

• Allergens – Dust mites, mold, pet dander, and pollen can trigger an immune response.

• Smoking and Secondhand Smoke – If your parents smoked during pregnancy, your risk of asthma is greater.

What Is Epigenetics and How Does It Affect Asthma?

Epigenetics is an amazing field that studies how your surroundings can switch genes on and off without actually modifying your DNA. For example, if your mother smoked while she was pregnant with you, this could alter the functionality of your genes to make you more likely to get asthma in the future. Other factors, such as stress, pollution, and diet, can similarly impact gene expression and susceptibility to asthma.

Genetic Testing and Asthma: What You Should Know?

You might wonder—can a genetic test tell you if you will get asthma? Currently, the answer is no. Although genetic testing can identify asthma susceptibility loci, the disease is influenced by so many genes that no single test can provide a simple answer. Genome-Wide Association Studies (GWAS) continue to find new genes associated with asthma, which, hopefully, in the future will allow us to create more precise diagnostic tools.

Can Asthma Be Treated on the Basis of Genetics?

Current and Future Genetic-Based Treatments

Pharmacogenomics—the study of how genes influence drug response—is transforming asthma treatment. Scientists are uncovering particular genetic markers that can predict how effectively a patient will react to medications like corticosteroids or biologics. This could lead to highly individualized treatments for asthma in the future.

Future Research Directions

Flourishing research in gene-editing technologies such as clustered regularly interspaced short palindromic repeats (CRISPR) - a natural defense mechanism in bacteria against viral infection, can one day provide promising avenues for the cure of asthma in the form of repairing defective genes. Precision medicine is also in progress, with customized treatment based on one's genetic and environmental makeup taking center stage. This could translate into more specific, side-effect-free therapies in the near future.

What's Next?

Future treatment for asthma could involve gene-editing drugs such as CRISPR, which can repair erroneous asthma-related genes.

Conclusion

While genes cannot be altered, we can alter the environment and lifestyle to decrease the chances of asthma development in the future. Continuing the research on the genes that identify the individual’s risk of developing asthma, the future seems to be with an asthma-free environment. One day, we might have really personalized medicines that make asthma a thing of the past.

Key Takeaway From iCliniq

Asthma genetics is an emerging field of research, and while we cannot yet cure or predict asthma from DNA, we are ever closer. In the meantime, managing environmental triggers and staying informed about new treatments can help those at risk lead healthier lives.