Genetics and genomics of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) fulfills criteria for a complex genetic disease in which environmental factors interact with multiple polymorphic genes to influence susceptibility. Finding the genes that influence susceptibility can be approached in hypothesis testing or unbiased study designs. In candidate gene association studies, genetic variation in, and/or levels of, expression of genes known or suspected to be involved in the pathogenesis of COPD are compared in affected and unaffected individuals. Although this approach is useful it is limited by our present knowledge of disease pathophysiology. Genomewide studies of gene expression and of genetic variation are now possible and are not constrained by our limited knowledge. Although both of these unbiased approaches are in their infancy, they have already provided exciting new avenues for future investigation and potentially now approaches to risk prediction and therapy.