We studied polymorphic variants at each of the 3 opioid receptor genes--OPRM1, OPRD1, and OPRK1, which encode the mu, delta, and kappa opioid receptors, respectively--including the OPRM1 Asn40Asp variant--as predictors of response to NTX or placebo in 215 alcohol-dependent male subjects who participated in Veterans Affairs Cooperative Study 425, "Naltrexone in the Treatment of Alcohol Dependence."
Therefore, our data provide no support for the idea that variations in OPRM1, OPRD1, PENK and POMC are associated with alcohol dependence or general illicit drug dependence, but variations in PENK and POMC appear to be associated with the narrower phenotype of opioid dependence in these families.
Taken together, our findings supported a positive association between OPRD1 variants and SD, and a positive haplotypic association between OPRK1 and AD in EAs.
Larger peaks (LOD scores >2.0) were typically found in regions previously identified in linkage studies and/or containing proposed candidate genes for alcoholism including AGT, CARTPT, OPRD1, PIK3R1, and PDYN.
Eleven single-nucleotide polymorphisms (SNPs) spanning OPRD1 were examined in 1063 European Americans (EAs) (620 cases with substance dependence (SD), including 557 with alcohol dependence (AD), 225 with cocaine dependence (CD) and 111 with opioid dependence (OD), and 443 controls).
The association of OPRD1 polymorphisms with both opioid addiction (OA) and cocaine addiction (CA) was analyzed in African American (OA n=336, CA n=503) and European American (OA n=1007, CA n=336) populations.