Genetics of asthma

Asthma is a complex disease with a phenotype that has been clinically diffi cult to define. Associated phenotypes including bronchial hyperresponsivene ss and atopy have provided useful objective alternatives in genetic and epi demiologic studies. Although asthma genes have not yet been identified, muc h progress has been made toward this goal. Genetic studies indicate that mu ltiple genes are involved in the pathogenesis of this disease, and chromoso mal regions likely to harbor asthma susceptibility genes have been replicat ed in several studies. Environmental factors, including smoking, diet, and viral respiratory infections, have also been implicated in the etiology of asthma. Directly linking these exposures as causes of asthma, however, has also proved difficult, Furthermore, interaction between susceptibility, gen es and environmental factors is probable and is a challenge currently being pursued by investigators worldwide. Understanding the fundamental gene-env ironmental interactions in the development of asthma should lead to earlier identification of susceptible individuals and more effective approaches fo r disease prevention.