We also conducted gene-based tests of association with previously examined candidate genes for ADHD (Table S1, available online). Several genes (ADRBK2, CHRNA4, COMT, DRD2, DRD4, HTR1E, HTR3B, MAOA, MAOB, PER1, PER2, SLC18A2, SLC6A2, SLC6A3, SLC6A4, TPH1, TPH2) contained no SNPs that were statistically significant at p<0.05. Of the remaining candidate genes examined, 19 had at least one significant association at p<0.05 (ADRA1A, ADRA1B, ADRA2A, ADRA2C, ADRB2, BDNF, DBH, DDC, DRD1, DRD3, HES1, HTR1B, HTR2A, HTR2C, NR4A2, SLC6A1, SNAP25, STX1A, SYT1), but these associations were not significant after adjusting for the number of tests conducted within each gene. Association results for genes with set-based tests that were significant genome-wide are presented in Table 4.
