Table 2. Analysis of Associations Between OPRD1 Genetic Variants and Treatment Outcome in Opioid-dependent European-Americans.

SNP ID	Minor allele	MAF	Position	Beta 1—methadone	P-value—methadone	Beta 2—buprenorphine	P-value—buprenorphine	P-value—G × E
rs1042114 (C27F)	G	0.12	Chr1:29138975	−0.07078	0.088	0.04655	0.33	0.062
rs678849	C	0.47	Chr1:29145188	0.01392	0.63	0.03414	0.28	0.64
rs10753331	A	0.35	Chr1:29164582	−0.01238	0.69	0.02400	0.44	0.41
rs529520	T	0.46	Chr1:29174946	−0.04248	0.15	0.02850	0.35	0.092
rs581111	T	0.27	Chr1:29175373	−0.02447	0.45	0.04398	0.23	0.16
rs2234918 (G307G)	C	0.43	Chr1:29189597	0.00253	0.93	0.00274	0.93	1.00

Abbreviations: G × E, gene × environment; MAF, minor allele frequency.

P-values were generated by linear regression for the individual treatment groups, as well as gene × environment analyses with treatment group as a covariate. The residue numbers and encoded amino acids of the synonymous and non-synonymous variants are included after the SNP IDs.