Nine samples containing AD phenotypes from seven independent studies participating in the Anxiety NeuroGenetics STudy (ANGST) Consortium were included in the meta-analysis. Standardized assessment instruments were used to generate DSM-based AD diagnoses, with some exceptions. The samples were genotyped on various SNP arrays according to their original study designs. Genotype calling, quality control (QC), imputation, and association analyses were performed at each site under similar standard protocols. SNP imputation was conducted within each sample using IMPUTE2 (19) or MACH (20) software utilizing the full 1000 Genomes Project reference data (March 2012, release v3). Genomic locations were based on NCBI build 37/UCSC hg 19 data. After imputation, SNPs with MAF<0.01, poor imputation quality <0.30, and Hardy-Weinberg equilibrium p-value <10−6 were removed. See Supplement for study descriptions and Supplemental Table S1 for details of genotyping and QC procedures. Table 1 summarizes basic statistics by cohort.
