Genetics of Asthma: A Review: Asthma: Conclusion
In an Australian population phenotyped for atopy and BHR, 172 affected sib-pairs were identified and screened with 269 markers spanning the entire genome. There was linkage of total serum IgE to the FceRI-P locus (chromosome llq) and to another locus on chromosome 16. BHR was linked to a locus on chromosome 4 and another on chromosome 7.
The Collaborative Study on the Genetics of Asthma is a large ongoing National Heart, Lung, and Blood Institute-sponsored study involving four centers. Families are ascertained through at least two affected siblings with asthma. Interim results have revealed some evidence for linkage of asthma to the following regions: chromosomes 5pl5 and 17pll.l-qll.2 in African-Americans; llpl5 and 19ql3 in whites; and; 2q33 and 21q21 in Hispanics. canadian health & care mall
These studies suggest that atopy, BHR, and asthma may have distinct genetic mechanisms because they demonstrate linkage to different chromosomal regions. Further, different regions have been linked to asthma and atopy in different ethnic and population groups, suggesting that the genetic mechanisms contributing to atopy and asthma vary between ethnic groups.
There has been tremendous effort worldwide to identify atopy and asthma genes. We are likely to see much more progress in the next few years. Progress in gene identification will come from both genome-wide searches and the candidate gene approach. Large population-based genome-wide searches are in progress worldwide, while continuing research into the basic biology of asthma will point us to additional candidate genes. Identification of asthma genes will be just the beginning for experiments in cellular and animal systems to elucidate function of the gene.
An understanding of the genes that predispose to asthma is likely to have a major impact on the way we treat asthma patients. First, knowledge of the function of asthma genes will elucidate new pathways of disease causation, which can lead to the development of novel therapeutic approaches. Second, individuals with different genetic variations may respond differently to therapy. Knowledge of an individual’s genotype may help us tailor treatment that is most appropriate for that individual. Third, genetic screening can help us identify individuals at risk for developing asthma so that they can be targeted at an early age for interventions like avoidance of allergens and cigarette smoke. Finally, if a major asthma gene is identified, a we may be able to design gene therapy for selected patients with severe asthma.