introduction
Asthma is characterized by inflammation of the airways that results in a narrowing of the air passages (called bronchi) in the lungs.
Symptoms include difficulty in breathing, wheezing, coughing, and a feeling of tightness in the chest. Asthma can be mild, with signs and symptoms occurring only with exercise or exposure to an allergen, or it can be severe and require frequent hospitalizations. In rare but very severe cases, asthma can be deadly.
Asthma is a common chronic disease, affecting over 300 million people around the world. Onset of asthma typically begins in childhood but it can also start later in life. Approximately 1 in every 10 people will develop asthma during their lifetime. In the United States, about 20 million people have been diagnosed with asthma; of these, nearly 9 million are children.
Genetic factors are known to play a significant role in the development of asthma. One common genetic variant near the ORMDL3 gene on chromosome 17 has been associated with an increased risk of developing childhood asthma.
The deCODEme Genetic Scan identifies the variant on chromosome 17 and provides an interpretation of the associated risk for the development of asthma in individuals of European and east Asian descent. Currently no data are available for people of other ethnicities for the variant.
risk factors
Although the cause of asthma is not currently known, studies have shown that some groups of individuals may be at greater risk of developing asthma than others. The main risk factors for asthma are:- Environmental risks: Risk of asthma may be higher in individuals who are regularly exposed to allergens, smoke, or chemicals; live in urban areas; or have a history of repeated respiratory infections during their childhood.
- Ethnicity: African Americans have higher rates of asthma than Americans of European descent.
- Age: Although asthma affects people of all ages, it often starts in childhood.
- Gender: Before puberty, asthma is more common among boys than among girls, but after adolescence more women than men are affected.
- Genetics: The risk for developing asthma is increased three- to six-fold in people who have a parent with asthma.
more information
You can find out more information about asthma by talking with your doctor and visiting these Web sites:
Asthma and Allergy Foundation of America
Center for Disease Control and Prevention
Global Initiative for Asthma
National Heart Blood and Lung Institute
World Health Organization (WHO)
Wikipedia Article on Asthma
Nature Article on Genetic Variants of ORMDL3 and the Risk of Asthma