Observed genes

Polygenic score

Influential genes: RAD50,CSMD1,TH2LCRR

The gene RAD50 is involved in DNA repair. Variants in this gene have been associated with an increased risk of asthma.

The CSMD1 gene is plays a role in immune regulation. Several changes in the CSMD1 gene have been associated with asthma susceptibility.

TH2LCRR is a regulatory region involved in the control of immune responses.

‍

Overview

Asthma is a chronic inflammatory disease of the bronchioles, the tubes that carry air in and out of the lungs. It is characterized by airflow obstruction and episodic exacerbations. Asthma attacks are usually triggered by a substance in the environment, named an allergen, such as dust, smoke, air pollution, animal fur, pollen, or perfume. Allergens are recognized by cells of the immune system, activating an immune reaction that causes the release of chemical substances that contract the muscle around the bronchioles leading to its narrowing. This phenomenon is called bronchoconstriction. 

However, not all asthma episodes are triggered by an allergen. Sometimes, cold climate, exercise, emotional stress, and even certain drugs such as aspirin can lead to bronchoconstriction. 

‍

Prevalence & Risk factors

Asthma is the most common chronic disease in children, and its prevalence is increasing, with an estimated 300 million people affected by this condition worldwide, according to the WHO.^[1] Mortality of asthma is uncommon and declining. Asthma typically starts at around three years old and might go away on its own before adulthood.  

In approximately 30% of children with asthma, the condition persists throughout their entire lives.^[8]

‍

Genetics

Asthma is a polygenic and multifactorial disorder. Therefore, numerous genes and factors contribute to its development. While environmental factors have been extensively studied in connection with asthma, genetics plays an equally crucial role in determining an individual's susceptibility to this condition. It is estimated that around 50% of the cases are linked to genetics and the other 50% to environmental factors.

Several genes have been linked to asthma development. These genes influence processes such as airway inflammation and bronchoconstriction. Mutations in these genes can increase an individual's chances of developing asthma.^[9,10]

Notably, allergens like dust mites, pollen, pet dander, and mold can trigger asthma symptoms in genetically susceptible individuals, while air pollutants such as particulate matter, ozone, nitrogen dioxide, and sulfur dioxide can exacerbate symptoms and increase the risk of asthma development. Prenatal and postnatal exposure to tobacco smoke also escalates the risk of asthma development. Moreover, viral respiratory infections, especially during early childhood, can heighten the risk of asthma development, as genetic factors shape one's immune response to these infections.^[11-13]

Genetic testing allows us to detect whether you have the predisposition to develop this disease. In Macromo, we use polygenic risk scores and causative evidence-based genetic variants for evaluation. The polygenic risk score (PRS) represents the total number of genetic variants that increase an individual's risk of developing a particular disease. All variants across their genome are summed and ranked according to their effect on disease development.

‍

Signs & Symptoms

Symptoms of asthma include:

• dry cough that gets worse at night
• shortness of breath
• wheezing due to bronchoconstriction (narrowing of the air passages)

In case of an acute exacerbation, symptoms like difficulty breathing, increased heart rate, and cyanosis (blue discoloration of the skin) – due to low oxygen in the blood (hypoxia). 

‍

Diagnosis

Asthma is diagnosed with pulmonary function tests. The most common are spirometry and skin prick allergy tests. 

It is essential to analyze allergies to determine which allergens are most likely to trigger an asthmatic episode. 

‍

Therapy

Inhaling corticosteroids and bronchodilators are the first-line therapy for asthma. In more severe cases, intravenous corticosteroids and oxygen might be needed.

Moreover, there exists a novel technique that can help prevent the narrowing of the bronchioles and improve asthma control. This procedure is called bronchial thermoplasty (BT), alternatively called thermal ablation for severe asthma. A catheter is slid through the bronchoscope and radiofrequency waves are applied to the bronchi to reduce smooth muscle mass within the respiratory system. Several clinical trials demonstrate improvement in quality of life and reduction in deterioration rates after treatment. BT is a safe and effective treatment option for severe asthma which is resistant to medical treatment.^[15]

‍

Prevention

Avoid allergens and substances that can trigger an episode if you have asthma. 

Growing up in rural areas is a protective factor and for children raised in the city it may be beneficial to have pets.

‍

Prognosis

Most people can achieve good control of their disease and live a normal life.

‍

Recommendations

• Ensure you have a diet rich in vitamin C, vitamin E, and zinc. 
• Avoid carpets and blankets where dust and allergens can accumulate.
• Clean your house often and opt for regular wet cleaning of the house.

‍