Other collaborative studies of multiple diseases have focused less on combining genotype-phenotype associations than on sharing methods for genotyping quality control, data analysis, imputation, and data distribution. Experience gained from early quality-control efforts in programs such as the Genetic Association Information Network (GAIN) of six complex diseases has been of great value in speeding the completion and analysis of geno-typing in later studies (19). Several other collaborative programs are currently in the pipeline (Table 1).
