Results of the most significant single SNP association tests are shown in Tables 1 and 2. Indication of association with heroin addiction was observed with seventeen SNPs (uncorrected P < 0.01) in the following genes: glutamate receptor, ionotropic, N-methyl D-aspartate (NMDA) subtype 2A, solute carrier family 29 (nucleoside transporters) member 1, dopamine receptor D1, alcohol dehydrogenase isozyme 7, 5-hydroxytryptamine (5-HT, serotonin) receptor, subtype 3A, glutamate decarboxylase isoforms 1 and 2, GABA-A receptor, subunit beta 3, diazepam binding inhibitor, cholinergic receptor, muscarinic 2, adrenergic receptor alpha-1A, and arginine vasopressin receptor subtype 1A. Listed in Table S2 are the alleles and genotype frequencies in cases and controls. Odds ratios were calculated for the minor allele and indicate a small effect (OR for risk effect range 1.54-1.94 and OR for a protective effect range 0.16-0.66 for the allelic test, Table 2). None of the tests were significant after correction for multiple testing. No significant effect was found for either age or gender.
