A series of coordinated GWA publications in early 2007 in prostate cancer, breast cancer, and myocardial infarction demonstrated the value of assessing association reports in multiple studies simultaneously (9). The joint publication of individual and combined associations with type 2 diabetes in three collaborating studies definitively showed the importance of combining individual-level genotype and phe-notype data in > 30,000 subjects to identify associations across several studies that no single study could reliably identify on its own (27–29). This approach was subsequently expanded by the addition of seven more diabetes studies in the Diabetes Genetics Replication and Meta-analysis (DIAGRAM) Consortium, with an effective sample size of > 50,000 (30). Similarly large efforts focused on a single phenotype or closely related phenotypes in tens of thousands of subjects have yielded variants related to obesity (31), lipids (32), height (33), and other traits.
