In total 7,350 samples were run through the HumanExome array. After QC screening we were left with useable genotype data for 7,244 subjects, including only one member of each MZ twin pair. Samples were dropped for a no-call rate of 0.5% or higher (145 samples), 16 samples were dropped because of sample mix-ups, four because of consent issues, and for all duplicate samples, only the one with the highest call rate was retained. After creating records for 1,120 MZ cotwins by copying genotype data of their MZ twins, the sample size useable for GWAS increased to 8,364 subjects, including all ethnic groups.
