What is asthma?
Over the last 20 years, the number of people with asthma in the Western world has doubled. About 5.4 million people in the UK have asthma. During an attack, the airways become inflamed, making them narrower. This causes wheezing, breathlessness and coughing. The triggers for an asthma attack vary, but may include allergy, cigarette smoke, infection and exercise.
What causes asthma?
How many genes have been associated with asthma?
Asthma tends to run in families. For most people, the risk of developing asthma is around 1 in 20, but if one of your parents has asthma, your risk rises to 1 in 4. Several genes are thought to be involved in asthma and other allergies. Some of them affect the immune system. There may be as many as 100 different genes involved. Research looks promising but it could be years before scientists know what they all are, and how they interact with other genetic and non-genetic factors.