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As the enzyme dopamine-beta-hydroxylase (DbetaH) converts dopamine to norepinephrine and both transmitters seem to be involved in the pathology of alcoholism and severe alcohol withdrawal symptoms, the gene encoding DbetaH (DBH) was applied to explore the genetic background of alcoholism and severe withdrawal symptoms. 102 healthy control subjects and 208 alcoholics, including 97 patients with a history of mild withdrawal symptoms, 57 with a history of alcohol withdrawal seizure (AWS) and 82 with a history of delirium tremens (DT) were genotyped for the DBH*444G/A polymorphism revealing a significantly elevated frequency of genotypes carrying the A-allele (p = 0.02; after Bonferroni adjustment for multiple tests) in alcoholics compared to healthy controls. Frequencies of alleles and genotypes of individuals with mild withdrawal symptoms did not differ significantly from those of patients with DT or AWS.

Aims: It was investigated whether the allele A9 of the dopamine transporter gene (DAT1; SLC6A3) is associated with alcoholism, delirium tremens (DT), alcohol withdrawal seizures (AWS), or the daily alcohol intake., Methods: A group of 102 healthy subjects and 216 alcoholics, including 97 patients with a history of mild withdrawal symptoms, 65 with a history of AWS and 83 with a history of DT were genotyped and personal data were achieved for statistical evaluation in a case-control design., Results: The frequency of individuals carrying the allele A9 [f(A9+)] was significantly higher (P = 0.01) in the group of alcoholics [f(A9+) = 0.48] compared with healthy controls [f(A9+) = 0.32]. There was no significant association of the allele A9 with severe withdrawal symptoms or the daily amount of alcohol consumed., Conclusions: Our results reveal that the allele A9 is strongly associated with alcoholism but not with withdrawal symptoms or daily alcohol intake.

The central dopamine system seems to influence addictive disorders. Plasma homovanillic acid (HVA) is an indicator of central dopaminergic activity. In this study the hypothesis that plasma HVA is associated with alcoholism or with delirium tremens (DT) during alcohol withdrawal was tested. A functional genetic polymorphism of the enzyme catechol-O-methyltransferase (COMT) that participates in converting dopamine into its final metabolite HVA was investigated for an association with alcoholism or DT during alcohol withdrawal. In addition, a relation between the functional polymorphism of COMT and plasma HVA concentrations was studied. Plasma HVA concentrations and COMT genotypes were determined in 142 German alcoholics and 101 German healthy controls. Alcoholic patients were examined after a minimum of 3 weeks after cessation of drinking. Mean plasma HVA concentrations were significantly lower in alcoholic patients compared to healthy controls. A group of alcoholics with a history of DT during alcohol withdrawal (n=62) did not differ significantly in plasma HVA concentrations from alcoholics with a history of only mild withdrawal symptoms (n=67). The functional polymorphism of the human COMT gene was neither significantly associated with the diagnosis of alcoholism or DT during alcohol withdrawal nor with plasma HVA concentrations.

Background: Norepinephrine and dopamine mediate important aspects of alcoholism and alcohol withdrawal. Dopamine-beta-hydroxylase (DbetaH) converts dopamine to norepinephrine. A recent study demonstrated a strong association between variance in plasma DbetaH activity and a novel polymorphism (DBH-1021C-->T) at the structural locus (DBH) encoding DbetaH protein., Methods: Our study investigated whether the DBH-1021C-->T polymorphism and plasma DbetaH activity were associated with alcoholism or with delirium tremens (DT) during alcohol withdrawal by analyzing 207 German alcoholic and 102 healthy control subjects. We also examined the influence of the polymorphism on enzyme activity., Results: Mean (+SD) plasma DbetaH activity measured in alcoholic subjects abstinent was significantly lower than that observed in control (27.7 + 16.7 vs. 35.6 + 18.8; p =.01). It did not differ between subjects with DT during withdrawal and subjects with mild withdrawal symptoms. The T allele of the DBH-1021C-->T polymorphism was significantly associated with lower plasma DbetaH activity. None of the alleles or genotypes were associated with alcoholism or DT., Conclusions: The data indicate that the alcoholism-related reduction in plasma DbetaH activity is independent of genotype at DBH-1021C-->T and replicate the finding that DBH-1021C-->T is strongly associated with plasma DbetaH activity in a native Western European population.