Table 2 summarizes the results of the total association test of QTDT with the P3 amplitude of the event-related potential in the posterior electrodes and the results of FBAT with diagnoses of alcohol dependence. Multiple significant genetic associations (p < 0.05) were identified with the P3 amplitude of ERP and the SNPs in the introns 1, 2, 3, and 4, and untranslated regions of exon 13 of the CRHR1 gene. These positive results were not because of population stratification as examined by the quantitative transmission disequilibrium test (QTDT) program (Abecasis et al., 2000) (p-values for population stratification are all >0.05). Of note, most SNPs that were significantly associated with the quantitative trait phenotype (P3 amplitude) were also associated with alcohol dependence.
