Susceptibility genes in severe asthma.

Asthma is a common complex disease with a very wide spectrum of severity. Although part of this may be due to differing environmental interactions and inadequate treatment, there is increasing evidence that in addition to susceptibility genes for asthma onset, there are also important genetic influences over the disease severity, response to treatment, and natural history. In this review, we bring together recent literature in the field of genetic influences over disease severity and discuss some of the clinical implications in terms of drug discovery and personalized medicine.