What do candidate gene association studies tell us about disease processes in COPD?
This complex picture is starting to show similarities to the quagmire that bedevils the field of asthma genetics. However, unlike asthma genetics, linkage studies in COPD have not been performed to identify regions of the genome likely to contain susceptibility genes, in which association studies with candidate genes may be more productive. The inconsistent results from case–control association studies are likely to relate to differences between study populations and the relatively small sizes of the populations under consideration. In addition, failure to account for population stratification differences between cases and controls within a particular study, and failure to correct adequately for the multiple comparisons involved in studying multiple polymorphisms with multiple phenotypes, is also likely to be problematic. However, several messages can be drawn from the association studies that have been undertaken to date. It is clear that many researchers continue to focus on the well
