Asthma is caused by a complex set of genes and environmental factors. Asthma is a chronic lung disease that causes a person's airways to tighten and inflame when exposed to different irritants or triggers.

Asthma is complicated because it is affected by the environment a person lives in and mutations in at least five different genes.  People with asthma have different kinds of mutations in these genes. Asthma runs in families, but because of its complex nature it is not yet possible to predict who will develop the disease. DNA sequencing can only reveal who might be at increased risk, and even then, the risk factor cannot yet be calculated.  This disease is caused by both genetic and environmental factors.