= 1, P = 0.054) [73]. Different patterns are observed in a group of American, Finish, and Native American subjects where the minor allele frequency of the rs1799971 SNP was 10.5-16.3% without any significant detection of the rs1799972 polymorphism [73]. A study by Bart et al (2004) also confirmed this association in a Swedish population of 139 opiate-dependent subjects and 170 controls, demonstrating higher frequencies of the minor allele in opiate-dependent users (χ2 = 10.27, d.f. = 1, p = 0.0014) [74]. These results support significant allelic variations between different ethnic groups that need to be accounted for when investigating the opioid receptor and other genes associated with opioid dependence.
