Asthma tends to run in families, which means that children are more likely to develop asthma if their parents have the condition. This indicates that there is a genetic component to asthma. It is not a single gene effect (such as some types of haemophilia or colour blindness), but many genes are involved. In addition to these genes, environmental influences are necessary for the development of asthma.
Better understanding of which genes contribute to asthma development will help us to predict which individuals are likely to develop the condition, and to better tailor treatment to individuals. Ultimately (though this is some way into the future) we’d like to be able to prevent development of asthma altogether.
This study was led by colleagues from the Departments of Health Sciences and Genetics, University of Leicester and studied the role of the beta-defensin genes (DEFB103, DEFB104 and DEFB4) in the development of asthma and Chronic Obstructive Pulmonary Disease (COPD). We were able to contribute DNA samples from over 600 members of the Leicester Cohorts. The study also included DNA from 1149 adults, some of whom had COPD. We found that the number of copies of the genes was not convincingly linked to the presence of COPD in the adults and although there was some weak evidence of a link to asthma in the children, this needs further research. There was also no association between lung function (measured by blowing tests) and the number of copies of these genes.
Although this study did not find strong links between copy number variation and COPD, asthma, or lung function, it is important to recognise that we have looked at one small piece of the jigsaw that constitutes the genetics of wheeze and asthma, and much more work remains to be done.