Genetics of asthma and atopy.

Asthma and airways hyperresponsiveness are the respiratory manifestations of sensitization to exogenous materials including protein allergens and chemical sensitizers that may trigger ongoing inflammation and respiratory symptomatology in those people who are predisposed to develop the asthmatic syndrome. That genetics plays a major role in this particular syndrome is without question, since twin studies have shown a greater prevalence of disease for monozygotic as opposed to dizygotic twins. There have been the beginnings of the development of an approach to a number of candidate genes for major genetic input in the asthmatic syndrome. However, unlike cystic fibrosis or even other autoimmune and inflammatory diseases such as juvenile diabetes and/or multiple sclerosis, a single gene or a significant set of major genes may not be easily identified. Rather the small contribution of multiple genes and/or sets of genes may be summed together and added to environmental exposure in people who will develop asthmatic syndromes. The identification of a genetic component to asthma would be of great significance. Even without a major or predominant gene, identification of the minor sets of genes interacting to cause asthma would represent a great advance. Knowledge of those minor genetic alleles involved in asthma susceptibility would allow great latitude in offering diagnostic screening and new therapeutic interventions in asthma.