Genetics of Asthma: What's New?

Asthma is a complex disorder involving a combination of genetic and environmental interactions that lead to airway inflammation characterised by TH2 T cell polarisation and airway wall remodelling accompanied by extensive epithelial dysfunction. Allergen exposure is the single most powerful environmental risk factor for asthma, although there are forms that accompany occupational exposures and forms where no allergen has been identified. Recently there has been an increase in morbidity associated with asthma and there is strong evidence that asthma and allergic disorders are increasing in prevalence and severity (see Chapter 1 in this series).