GWA studies represent a powerful new tool for identifying genetic variants related to complex diseases, but they also have important limitations, including their potential for false-positive results and lack of sensitivity to detect rare variants. Their primary uses for the foreseeable future are likely to be in the investigation of biologic pathways of disease causation and normal health and development. Clinical application of these findings will require firm evidence that testing for them adds information to known risk factors, that effective interventions are available, that improved outcomes justify the associated costs, and that obtaining this information does not have serious adverse consequences for patients and their families. Although most GWA findings are clearly several steps removed from main- stream clinical use at present, functional investigation and experimental application of these findings are expected to produce new advances in the prevention and treatment of common diseases.
