title: Association between the catechol-O-methyltransferase Val158Met polymorphism and cocaine dependence.
abstract: Dopaminergic brain systems have been documented to have a major role in drug reward, thus making genes involved in these circuits plausible candidates for susceptibility to substance use disorders. The catechol-O-methyltransferase (COMT) is involved in the degradation of catecholamines and a functional polymorphism (Val158Met) has been suggested to influence enzyme activity. In this study we hypothesize that genetic variation in the COMT gene contributes to increased risk for cocaine dependence. Cocaine-dependent individuals (n=330) and screened unaffected normal controls (n=255) were genotyped for three SNPs in the COMT gene (rs737865, rs4680 (Val158Met), rs165599). All cases and controls were of African descent. Genotype and allele frequencies differed significantly for the Val158Met polymorphism between cases (f(Met)=35%) and controls (f(Met)=27%) (p=0.004; corrected p=0.014; OR 1.44; 95% CI 1.12-1.86). Haplotype analysis showed a significant association for a two-marker haplotype rs737865-Val158Met (p=0.005). Results suggest that variation in COMT increases risk for cocaine dependence. The low enzyme activity 158Met allele or haplotypes containing this variant might have functional effects on dopamine-derived reward processes and cortical functions resulting in increased susceptibility for cocaine dependence. Additional studies are required to elucidate the role of COMT in the pathophysiology of substance use disorders.
authors.affiliation: Department of Psychiatry, Translational Research Laboratories, Center for Neurobiology and Behavior, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. lohoff@mail.med.upenn.edu
authors.forename: Falk W
authors.initials: FW
authors.lastname: Lohoff
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Weller
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Bloch
authors.forename: Aleksandra H
authors.initials: AH
authors.lastname: Nall
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Ferraro
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Kampman
authors.forename: Helen M
authors.initials: HM
authors.lastname: Pettinati
authors.forename: David W
authors.initials: DW
authors.lastname: Oslin
authors.forename: Charles A
authors.initials: CA
authors.lastname: Dackis
authors.forename: Charles P
authors.initials: CP
authors.lastname: O'Brien
authors.forename: Wade H
authors.initials: WH
authors.lastname: Berrettini
mesh_terms: D000328:Adult; D001741:Black or African American / Q000235:genetics; D019943:Amino Acid Substitution / Q000235:genetics; D001923:Brain Chemistry / Q000187:drug effects / Q000235:genetics*; D016022:Case-Control Studies; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D003042:Cocaine / Q000494:pharmacology; D019970:Cocaine-Related Disorders / Q000201:enzymology* / Q000235:genetics* / Q000503:physiopathology; D004252:DNA Mutational Analysis; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D008297:Male; D008715:Methionine / Q000235:genetics; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics*; D014633:Valine / Q000235:genetics
chemical_list: D018765:Dopamine Uptake Inhibitors; D008715:Methionine; D002394:Catechol O-Methyltransferase; D014633:Valine; D003042:Cocaine