In the last 5 years, multiple studies have been performed in individuals from Australia, The United States, Germany, France, The Netherlands, China, and the United Kingdom4–6,8–15 These studies have contributed significantly to the mapping of allergy and asthma genes by conducting genome-wide screens in different human populations. These approaches use linkage analysis to identify regions of the genome that are statistically linked to a specific phenotype. Table 1
lists genetic term definitions. Results of linkage analysis are usually expressed as a lod score (log of the odds) for a trait to be linked to a specific chromosomal region. One example of this method is the genome-wide screen performed in Hispanic families from New Mexico,11 (Fig 2
). Regions of interest observed in the Hispanic population include chromosomes 1p, 2q, 5q, 11p, 12q, 14q, 17q, and 21q. Authors from the Collaborative Study on the Genetics of Asthma (CSGA),11 also demonstrated evidence for gene-gene interactions using analytic techniques showing interrelationships between different chromosomal regions (Fig 3
). These data support our hypothesis that several genes interact in the development of asthma.