. . . . . . . . . . . . "[We tested the hypothesis that the alleles at the (CA)n repeat of the proenkephalin gene (PENK) might be associated with opioid addiction in 31 non-Hispanic Caucasian subjects with opioid dependence (heroin), 89 ethnically matched subjects with substance dependence other than opioid dependence and 132 controls.]. Sentence from MEDLINE/PubMed, a database of the U.S. National Library of Medicine."@en . . . . . "2015-02-27"^^ . . "Gene-disease associations inferred from text-mining the literature."@en . "DisGeNET evidence - LITERATURE"@en . "2015-08-25T14:43:48+02:00"^^ . . . . . . . . . . . "v3.0.0.0" . "v3.0.0" .