Table 2 summarizes the top four significant SNPs (with P < 1.0 × 10−4) in gene NCK2 on chromosome 2 (2q12) for opiates dependence in African-origin men. We identified a genome-wide significant SNP (rs2377339 with P = 1.33 × 10−11) for the opiates dependence in African-origin men by the allelic test. Logistic regression also yielded strong evidence for the association between the SNP rs2377339 (P = 1.01 × 10−7) and opiates dependence although the P-value did not reach the genome-wide significance threshold. In addition, Table 2 presents the association results for the other five addictions with the four candidate SNPs. None of the four SNPs appeared significantly associated with the other five substance addictions.
