Two SNPs were selected for genotyping in the EA heroin and cocaine addicted population: rs17174794 and rs62638690. rs17174794 changes the amino acid sequence of MOR from a cysteine to a serine at position 147 in the protein (S147C), while the minor allele of rs62638690 changes a cysteine to a phenylalanine at position 192 (C192F). The two SNPs selected for genotyping in the AA drug addicted population are rs17174801 and rs1799971. rs17174801 changes the amino acid sequence from an asparagine to an aspartic acid at position 152 (N152D). rs1799971 is the well-studied A118G SNP which changes an asparagine to an aspartic acid at position 40 (N40D). Polyphen [1] predicts each of these 4 SNPs to have a ‘probably damaging’ effect on protein function.
