Mapping the Genes for IgE Production and Allergy

Abstract

Human beings are complex organisms living in a complex environment. Not surprisingly, common human diseases like atopic allergy, and especially asthma, are complex. First, allergy is multifactorial, that is to say, the expression of the disease is influenced by interactions between multiple major and minor genes as well as by non-genetic factors such as the degree of allergen exposure. Second, like many other complex human diseases, allergy is likely to be genetically heterogeneous (many distinct genes, or groups of genes, lead to similar clinical phenotypes). Two levels of genetic heterogeneity should be considered: (i) the different categories of allergic disease (asthma, allergic rhinitis, eczema, etc.) may be associated with different groups of genes, and (ii) for each characteristic disease sub-phenotype (such as asthma) several distinct groups of major genes may be involved in the expression of the particular condition. Thus, the picture of allergic disease that is emerging is one comprised of overlapping constellations of genes that interact in an indefinitely large number of ways with a wide variety of environmental factors. Such interactions often lead to the expression of allergic rhinitis and, less commonly, to asthma.