both African (case n = 125, control n = 100) and European (case n = 200, control n = 150) ancestry. A single intergenic variant (rs10494334) was significant in the patients of European descent after multiple testing correction (p = 0.035), whereas no SNPs were significant in African-Americans. Another relatively small GWAS of Han Chinese patients diagnosed with heroin dependence (case n = 370, control n = 134) did not identify any variants reaching genome-wide significance (p < 5 × 10−8) [38].
