Genetic Risk Prediction — Are We There Yet?

Amajor goal of the Human Genome Project was to facilitate the identification of inherited genetic variants that increase or decrease the risk of complex diseases. The completion of the International HapMap Project and the development of new methods for genotyping individual DNA samples at 500,000 or more loci have led to a wave of discoveries through genomewide association studies. These analyses have identified common genetic variants that are associated with the risk of more than 40 diseases and human phenotypes. Several companies have begun offering directto-consumer testing that uses the same single-nucleotide polymorphism chips that are used in genomewide association studies. These companies claim that such testing should be made available to consumers who are interested in their personal level of risk for the relevant diseases. Now, “risk tests” for specific diseases such as breast cancer are also being marketed to physicians and consumers. 1