The contribution of polymorphism in the alcohol dehydrogenase beta subunit to alcohol sensitivity in a Japanese population

Application of aldehyde dehydrogenase 2 (ALDH2) Genetic Diagnosis in Support of Decreasing Alcohol Intake

Encouraging behavioral changes to decrease alcohol intake is not easy from the standpoint of health support. This study was conducted to examine whether the genetic diagnosis of ALDH2 polymorphism is useful in supporting those who want to decrease their alcohol intake. The participants in this study were 329 male employees who wanted to know the result of their ALDH2 genotype. We divided the 329 participants randomly into two groups. One was the "notified group" (n=157), and the other was the "non-notified group" (n=172). The subjects belonging to the "notified group" were informed of the results of the ALDH2 genotype diagnosis in April, 2003. Drinking habits and laboratory data were obtained before and after notification of the ALDH2 genotype. Among those with genotype ALDH2*1/*1, there was no significant change in drinking frequencies, nor was there any significant decline in liver function laboratory data in either of the groups before and after notification of the genotype. However, weekly alcohol intake tended to increase compared to that before notification. On the other hand, with regard to those with genotype ALDH2*1/*2, no significant changes in drinking frequencies or liver function laboratory data were evident in either group before and after notification of the genotype. However, the weekly alcohol intake tended to increase in the non-notified group, whereas it tended to decrease in the notified group. Although the result was not significant, it is suggested that, with further study and an increased sample size, the genetic diagnosis may be found to be useful.

Genetic associations of alcohol and aldehyde dehydrogenase with alcohol dependence and their mechanisms of action

Two alcohol dehydrogenase genes (ADHIB and ADH1C on chromosome 4) and one aldehyde dehydrogenase gene (ALDH2 on chromosome 12) exhibit functional polymorphisms that are associated with lower rates of alcohol dependence. The ALDH2*2 allele,found almost exclusively in Asian populations, has the strongest relationship. The ADH1B*2, ADH1B*3, and ADHlC*i alleles, found in varying prevalence in different ethnic groups, have also been associated with lower rates of alcohol dependence. Studies of the ADHIBand ADH1C haplotypes, however, have shown that ADH1C*I is in linkage disequilibrium with ADHiB*2, and the ADH1C*i allele does not appear to have significant unique associations with alcohol dependence. The hypothesized mechanism underlying the associations of the ADH1B and ALDH2 polymorphisms with alcohol dependence is that the isoenzymes encoded by these alleles lead to an accumulation of acetaldehyde during alcohol metabolism. Based on their kinetic properties, ALDH2 *2 theoretically should lead to a slower removal of acetaldehyde than ALDH2*1, whereas ADH1B*2 and ADH1B*3 should lead to a more rapid production of acetaldehyde than ADHIB*I. It is further hypothesized that elevations in acetaldehyde cause more intense reactions to alcohol and lead to lower levels of alcohol intake. Data are consistent with the hypothesis that elevations in acetaldehyde, increased sensitivity to alcohol, and lower levels of drinking reflect the mechanism by which the ALDH2*2 allele reduces risk for alcohol dependence. There is also some evidence supporting this mechanism for the ADH1B*2 and ADHIB*3 alleles, but the results are less consistent. These findings highlight the value of trying to elucidate the mechanism by which genes ultimately give rise to differences in alcohol dependence through the examination of mediating behaviors.

Alcohol Dehydrogenase 2 His47Arg Polymorphism Influences Drinking Habit Independently of Aldehyde Dehydrogenase 2 Glu487Lys Polymorphism: Analysis of 2,299 Japanese Subjects

Although the functional effect of alcohol dehydrogenase 2 (ADH2) His(47)Arg polymorphism has been elucidated, its effect on habitual drinking remains unknown. Here, we conducted a cross-sectional study in 2,299 nonalcoholic Japanese subjects (989 men and 1,310 women). Drinking status, ethanol consumption, and physical reaction to one glass of beer were examined with regard to ADH2 and aldehyde dehydrogenase 2 (ALDH2) polymorphism. Strength of associations were assessed by age-, sex-, smoking status-, and genotype-adjusted odds ratios and their 95% confidence intervals. ADH2 His/Arg and Arg/Arg genotypes showed higher risk for habitual drinking. Among men, ALDH2 genotype- and confounder-adjusted odds ratios (95% confidence intervals) were 1.30 (0.89-1.89) and 3.16 (1.03-9.70), and this trend was significant (P = 0.024). A similar trend was observed among women. The combination genotypes of two polymorphisms revealed the clear effect of the ADH2 Arg allele among those with ALDH2 Glu/Lys in both sexes (P(trend) = 0.007 for men and 0.024 for women). Physical reactions, such as flushing and palpitation, were significantly less common in those with Arg/Arg compared with other ADH2 genotypes, and this was marked when combined with ALDH2 Glu/Lys. Heavy drinker status was also strongly associated with ADH2 Arg alleles. In conclusion, this study showed the strong effect of ADH2 His(47)Arg polymorphism on habitual drinking regardless of ALDH2 genotype.

Blood pressure, levels of serum lipids, liver enzymes and blood glucose by aldehyde dehydrogenase 2 and drinking habit in Japanese men

OBJECTIVES

The association of blood pressure and levels of serum lipids, liver enzymes, blood glucose and aldehyde dehydrogenase 2 (ALDH2) with drinking habit was examined in Japanese men.

METHODS

The subjects were 264 men aged 39 to 80 years who were classified into the ALDH2 deficiency or sufficiency group using the ethanol patch test and the Tokyo University ALDH2 Phenotype Screening Test. A self-administered questionnaire including drinking habit was used. Blood pressure and the levels of biochemical markers in groups with ALDH2 sufficiency, ALDH2 deficiency and drinking habit were compared using multiple regression models for adjusting age, smoking habit, physical exercising habit and body mass index.

RESULTS

The levels of serum high-density lipoprotein cholesterol, triglycerides, aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (γ-GTP) were significantly higher in current drinkers of 20 g of ethanol or more per day than in nondrinkers of the ALDH2 sufficiency group. The levels of serum AST and γ-GTP in current drinkers of 20 g of ethanol or more per day, and fasting blood sugar in current drinkers of less than 20 g of ethanol per day were significantly higher than those in nondrinkers of the ALDH2 deficiency group.

CONCLUSIONS

These results suggest that alcohol consumption increases the levels of serum lipids and liver enzymes in ALDH2-sufficient individuals and liver enzymes and blood glucose levels in ALDH2-deficient individuals.

Genetic associations of alcohol dehydrogenase with alcohol use disorders and endophenotypes in white college students

Associations of alcohol dehydrogenase (ADH) gene polymorphisms (ADH1B*2 and ADH1C*1) with a lifetime alcohol use disorder (AUD) were examined in White college students. Alcohol-related endophenotypes likely to be influenced by elevations in acetaldehyde were also assessed. Individuals with an ADH1B*2 allele had lower rates of AUDs, consumed a lower maximum number of drinks in a 24-hr period, reported a greater level of response to alcohol, were more likely to have experienced alcohol-induced headaches following 1 or 2 drinks, and reported more severe hangovers than those lacking this allele. These findings are consistent with the hypothesis that enhanced sensitivity to alcohol and lower levels of alcohol use reflect the mechanism by which ADH1B*2 protects against developing an AUD.

A gene-gene interaction between ALDH2 Glu487Lys and ADH2 His47Arg polymorphisms regarding the risk of colorectal cancer in Japan

Alcohol consumption is recognized as a potential risk factor for colorectal cancer (CRC). Genetic polymorphisms, aldehyde dehydrogenase (ALDH2) Glu487Lys and alcohol dehydrogenase 2 (ADH2) His47Arg, which have a strong impact on alcohol metabolism, are common in Japanese population but their significance for CRC carcinogenesis remains to be clarified in detail. We, therefore, conducted a matched case-control study with 257 incident CRC cases and 771 non-cancer controls at Aichi Cancer Center, including analysis of interactions between polymorphisms, drinking and folate consumption. The ADH2 Arg allele was found to be associated with increased risk, the odds ratios (ORs) being 1.35 (95% confidence interval: 1.00-1.84) and 1.93 (1.06-3.53) for the His/Arg and Arg/Arg genotypes, respectively. In contrast, no apparent links were observed with the ALDH2 genotypes. Individuals having ALDH2 Glu/Glu with ADH2 Arg+, ALDH2 Lys+ with ADH2 His/His and ALDH2 Lys+ with ADH2 Arg+ showed ORs of 0.10(0.04-0.21), 0.10 (0.06-0.19) and 1.36 (0.94-1.97), respectively, compared with ALDH2 Glu/Glu with ADH2 His/His. Statistical gene-gene interaction was significant between the two polymorphisms for the risk of CRC (P< 0.001). The impact of ALDH2 Lys+ with ADH2 Arg+ was more evident in low folate consumer (OR = 2.32, 1.19-4.55) than high folate consumer (OR 1.38, 0.80-2.38). In conclusion, while we failed to find any significant association with the ALDH2 polymorphism itself, significant interaction between ALDH2 and ADH2 polymorphism was observed. Replication in the future study is warranted.

Influence of alcohol consumption and gene polymorphisms ofADH2andALDH2on hepatocellular carcinoma in a Japanese population

Although alcohol intake as well as hepatitis viruses has been associated with hepatocellular carcinoma (HCC), gene-alcohol interactions on HCC risk remain to be elucidated. We conducted a case-control study to examine whether polymorphisms of alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2) modified the HCC risk depending on the amount of alcohol intake. ADH2 and ALDH2 genotyping was performed by a duplex polymerase chain reaction with confronting two-pair primers in 209 newly diagnosed HCC cases and 2 different controls [275 hospital controls and 381 patients with chronic liver disease (CLD)]. Multiple logistic regression analyses revealed that heavy drinkers consuming >or=3 "go"s/day of sake (69 g of ethanol/day) showed an increased risk of HCC based on comparison of HCC cases with hospital controls [adjusted odds ratio (OR) = 13.5; 95% confidence interval (CI) 3.3-54.3] or CLD patients (adjusted OR = 7.0; 95% CI 2.5-19.2), whereas the overall risk was not elevated among light to moderate drinkers consuming <3 "go"s/day. Interestingly, light to moderate drinking was associated with an increased risk among those with ALDH2*1/*2 (adjusted OR = 4.5 or 2.0), but not among those with ALDH2*1/*1 (adjusted OR = 0.8 or 1.0; p interaction = 0.03 or 0.13). However, this gene-alcohol interaction was not observed for heavy drinking. Among light to moderate drinkers, people with the combination of ALDH2*1/*2 and ADH2*2/*2 revealed the highest risk of HCC. These findings indicate that the ALDH2 polymorphism may modify HCC risk among light to moderate drinkers.

Gene-environment interactions in human diseases

Studies of gene-environment interactions aim to describe how genetic and environmental factors jointly influence the risk of developing a human disease. Gene-environment interactions can be described by using several models, which take into account the various ways in which genetic effects can be modified by environmental exposures, the number of levels of these exposures and the model on which the genetic effects are based. Choice of study design, sample size and genotyping technology influence the analysis and interpretation of observed gene-environment interactions. Current systems for reporting epidemiological studies make it difficult to assess whether the observed interactions are reproducible, so suggestions are made for improvements in this area.

Duplex polymerase chain reaction with confronting two-pair primers (PCR-CTPP) for genotyping alcohol dehydrogenase beta subunit (ADH2) and aldehyde dehydrogenase 2 (ALDH2)

AIMS

Alcohol dehydrogenase beta subunit (ADH2) Arg47His and aldehyde dehydrogenase 2 (ALDH2) Glu487Lys were genotyped by a duplex polymerase chain reaction (PCR) with confronting two-pair primers (PCR-CTPP), which allows DNA amplification with one-tube PCR including eight primers, and subsequent electrophoresis.

METHODS

Several PCR conditions were tested to establish the optimal conditions for distinguishing the allele-specific bands for the two polymorphisms. Under the optimal PCR conditions, 454 Japanese health check-up examinees were genotyped.

RESULTS

The allele-specific bands were successfully amplified under the optimal conditions of the duplex PCR-CTPP. The genotype distributions were within the Hardy-Weinberg equilibrium. The bands produced by the duplex PCR-CTPP genotyping were clearer than those produced by PCR-CTPP, conducted solely for ADH2.

CONCLUSIONS

ADH2 Arg47His and ALDH2 Glu487Lys were successfully genotyped by this newly developed duplex PCR-CTPP, an inexpensive and time-saving genotyping tool, which will be useful in epidemiological studies on alcoholism, as well as risk estimation of alcohol-related diseases.

Relation among alcohol dehydrogenase 2 polymorphism, alcohol consumption, and levels of gamma-glutamyltransferase

In human beings, alcohol is metabolized primarily by alcohol dehydrogenase 2 (ADH2) and acetaldehyde dehydrogenase 2 (ALDH2). Whereas polymorphisms of the ALDH2 are common in Asian persons, polymorphisms of the ADH2 seem to be more important in Caucasian individuals. The aim of this study was to assess the relation among ADH2 polymorphism, alcohol consumption, and levels of gamma-glutamyltransferase (GGT). The question was examined among 1,663 subjects (736 men and 927 women) participating in a national representative health and nutrition survey (VERA substudy of the German National Nutrition Survey). Alcohol consumption was assessed through responses to a semiquantitative food frequency questionnaire (FFQ), and the ADH2 restriction fragment length polymorphism (RFLP) Mae III and GGT levels were analyzed from frozen serum samples. The relations between the polymorphism and alcohol consumption and between alcohol consumption and GGT levels according to the polymorphism were assessed with the use of descriptive statistics and contingency table analysis. Of the subjects studied, 2.8% were homozygous or heterozygous for the ADH2*2 allele, and high levels of alcohol consumption (>20 g/day) were less common among these subjects (8.5%) than among subjects with the ADH2*1 allele (19.9%). Median levels of GGT increased with increasing levels of alcohol consumption. This increase tended to be stronger among subjects with the ADH2*2 allele than among other subjects, although differences were not statistically significant (P value for interaction=.1) given the small number of subjects with the polymorphism. These results are consistent with the hypothesis that subjects with the ADH2*2 allele, on the one hand, might tend to drink less alcohol but, on the other hand, might be at increased risk of alcohol-related effects on the liver with consumption of larger amounts of alcohol. However, this hypothesis needs to be evaluated among larger population samples.

Influence of ADH1B polymorphism on alcohol use and its subjective effects in a Jewish population

Class I alcohol dehydrogenases (ADHs) are the principal enzymes responsible for ethanol metabolism in humans. Genetic polymorphism at the ADH1B locus (old nomenclature ADH2) results in isozymes with quite different catalytic properties. The frequency of the ADH1B*2 allele varies among ethnic groups. ADH1B*2 is most often observed in Asian populations, and has been shown to be protective against alcoholism. The Jewish population has a higher frequency of the ADH1B*2 allele and lower rates of alcohol-related problems as compared to other Caucasian populations. Thus, it would be of interest to determine whether the ADH1B*2 allele is associated with alcohol consumption and its subjective effects in this group. Four groups of Jewish subjects (male and female college-age samples, and male and female general samples) were recruited from the same region of the United States. All subjects completed a questionnaire to delineate alcohol consumption and its subjective consequences. Genotype at the ADH1B locus was determined for each participant. ADH1B*2 allele frequencies were similar for the Jewish college-age and general population samples. Men in both the college-age and general population in the ADH1B*2 group reported more unpleasant reactions following alcohol consumption than men in the ADH1B*1 group. Men in the general population in the ADH1B*2 group drank alcohol less frequently than men who were homozygous ADH1B*1; there was a similar trend among the women. The ADH1B polymorphism is associated with unpleasant reactions after alcohol consumption, and frequency of alcohol consumption in these Jewish samples.

Lifestyle habits and genetic susceptibility and the risk of esophageal cancer in the Thai population

The association of lifestyle habits and polymorphism of ADH2 and ALDH2 genes with the risk of esophageal cancer in Thai population was investigated in a hospital-based case-control study: 202 cases and 261 controls. The results of multivariate logistic analysis showed that alcohol consumption >60g/day, smoking >10 cigarettes/day and chewing betel >or=10 quids/day significantly increased risk (odds ratio (OR) 5.84, 95% confidence interval (CI) 3.15-10.83; 4.65, 95% CI 1.99-10.84; and 4.68, 95% CI 2.05-10.72, respectively). ADH2*1/*1 also increased the risk significantly (OR 1.56, 95% CI 1.01-2.39) while ALDH2 did not (OR of ALDH2*1/*2 1.57, 95% CI 0.89-2.76). However, the combined at risk genotypes, ADH2*1/*1 and ALDH2*1/*2 increased risk to four-fold. In addition, significant gene-environment interaction was found. Heavy drinkers >60g/d harboring ADH2*1/*1 or ALDH2*1/*2 had about an 11-fold increased risk.

Interaction between alcohol dehydrogenase II gene, alcohol consumption, and risk for breast cancer

MaeIII Restriction Fragment Length Polymorphism in exon 3 of the alcohol dehydrogenase II was assessed in serum from 467 randomly selected German women and 278 women with invasive breast cancer to evaluate the interaction between a polymorphism of the alcohol dehydrogenase II gene, alcohol consumption and risk for breast cancer. In both groups, usual consumption of different alcoholic beverages was asked for using semiquantitative food frequency questionnaires. We used multivariable logistic regression to separately estimate the association between alcohol consumption and alcohol dehydrogenase II polymorphism in the population sample and women with breast cancer. The alcohol dehydrogenase II polymorphism was detected in 14 women from the population sample (3.0%) and in 27 women with invasive breast cancer (9.7%). Frequency of alcohol consumption was independent of the genotype in the population sample. In women with breast cancer, there was a significant inverse association between the alcohol dehydrogenase II polymorphism and frequency of alcohol consumption (adjusted case-only odds ratio over increasing frequency of alcohol consumption=0.5; P for interaction=0.02). We observed a gene-environment interaction between the alcohol dehydrogenase II polymorphism, alcohol consumption, and risk for breast cancer. Breast cancer risk associated with alcohol consumption may vary according to the alcohol dehydrogenase II polymorphism, probably due to differences in alcohol metabolism.

Relationship between Genetic Polymorphisms of Alcohol-metabolizing Enzymes and Changes in Risk Factors for Coronary Heart Disease Associated with Alcohol Consumption

Background: There are large individual variations in the responses of risk factors for coronary heart disease to alcohol consumption. To clarify the factors responsible for these individual variations, we studied the relationship between blood pressure, serum lipids, and uric acid and the genetic polymorphisms of alcohol dehydrogenase (ADH) 2 and aldehyde dehydrogenase (ALDH) 2 in alcohol drinkers.

Methods: We examined 133 male workers who drank &gt;300 g of alcohol per week. Information regarding lifestyle habits was obtained by questionnaire. The ADH2 genotype was determined by PCR and subsequent digestion with MaeIII. The ALDH2 genotype was determined based on amplified product length polymorphisms.

Results: When the workers were divided into three groups: the ADH21/21, ADH21/22, and ADH22/22 groups, the mean triglycerides and γ-glutamyl transpeptidase concentrations were significantly higher in the ADH22/22 group than in the ADH21/21 group. In addition, multiple logistic regression analysis showed that the frequencies of individuals whose systolic blood pressure, triglycerides, and uric acid values were in the highest one third were significantly higher in the ADH22/22 group than in the ADH21/21 group. In contrast, no difference was observed between the ALDH21/21 and (ALDH21/22 + ALDH22/22) groups with regard to the mean value of any variable and to the frequency of individuals with any variable value in the highest one third.

Conclusion: Individuals with the ADH21/21 genotype might suffer fewer negative effects of drinking.

Relationship of the delta-opioid receptor gene to heroin abuse in a large Chinese case/control sample

Pharmacological and electrophysiological evidence has shown that opioid receptors are involved in the mechanism of heroin dependence. Thus, opioid receptors are appropriate candidate genes for case-control association studies of heroin dependence. Previously, two single nucleotide polymorphisms (SNPs), OPRD1 921T > C and 80G > T, of the human delta opioid receptor gene were used in population-based studies of heroin dependence. One study in a German population found that OPRD1 921T > C was associated with heroin dependence. This finding, however, was not replicated in a different German sample. To test the hypothesis that OPRD1 or a closely linked gene is associated with heroin dependence, we used 5' nuclease assays to genotype both OPRD1 SNPs in 450 Chinese heroin dependent patients and 304 unaffected controls from the same population. In addition, five SNPs distributed in four other genes: ADH2, ALDH2, OPRM1, and DRD1, were used as genomic control loci to test the case and control populations for stratification bias. Genotype and allele frequencies at OPRD1 921T > C were not significantly different, and the OPRD1 80G was absent from both Chinese opioid dependence patients and controls. Based on the genotype and allele frequencies of the genomic control loci, there was no evidence for stratification bias capable of masking an association of OPRD1 to heroin dependence in this large and homogenous Chinese sample. Therefore, these data do not support an association between the OPRD1 gene and heroin dependence in the Chinese population.

The role of acetaldehyde in the actions of alcohol (update 2000)

BACKGROUND

Recent advances in the field of acetaldehyde (AcH) research have raised the need for a comprehensive review on the role of AcH in the actions of alcohol. This update is an attempt to summarize the available AcH research.

METHODS

The descriptive part of this article covers not only recent research but also the development of the field. Special emphasis is placed on mechanistic analyses, new hypotheses, and conclusions.

RESULTS

Elevated AcH during alcohol intoxication causes alcohol sensitivity, which involves vasodilation associated with increased skin temperature, subjective feelings of hotness and facial flushing, increased heart and respiration rate, lowered blood pressure, sensation of dry mouth or throat associated with bronchoconstriction and allergy reactions, nausea and headache, and also reinforcing reactions like euphoria. These effects seem to involve catecholamine, opiate peptide, prostaglandin, histamine, and/or kinin mechanisms. The contribution of AcH to the pathological consequences of chronic alcohol intake is well established for different forms of cancer in the digestive tract and the upper airways. AcH seems to play a role in the etiology of liver cirrhosis. AcH may have a role in other pathological developments, which include brain damage, cardiomyopathy, pancreatitis, and fetal alcohol syndrome. AcH creates both unpleasant aversive reactions that protect against excessive alcohol drinking and euphoric sensations that may reinforce alcohol drinking. The protective effect of AcH may be used in future treatments that involve gene therapy with or without liver transplantation.

CONCLUSIONS

AcH plays a role in most of the actions of alcohol. The individual variability in these AcH-mediated actions will depend on the genetic polymorphism, not only for the alcohol and AcH-metabolizing enzymes but also for the target sites for AcH actions. The subtle balance between aversive and reinforcing, protecting and promoting factors will determine the overall behavioral and pathological developments.

The role of acetaldehyde in the actions of alcohol (update 2000)

BACKGROUND

Recent advances in the field of acetaldehyde (AcH) research have raised the need for a comprehensive review on the role of AcH in the actions of alcohol. This update is an attempt to summarize the available AcH research.

METHODS

The descriptive part of this article covers not only recent research but also the development of the field. Special emphasis is placed on mechanistic analyses, new hypotheses, and conclusions.

RESULTS

Elevated AcH during alcohol intoxication causes alcohol sensitivity, which involves vasodilation associated with increased skin temperature, subjective feelings of hotness and facial flushing, increased heart and respiration rate, lowered blood pressure, sensation of dry mouth or throat associated with bronchoconstriction and allergy reactions, nausea and headache, and also reinforcing reactions like euphoria. These effects seem to involve catecholamine, opiate peptide, prostaglandin, histamine, and/or kinin mechanisms. The contribution of AcH to the pathological consequences of chronic alcohol intake is well established for different forms of cancer in the digestive tract and the upper airways. AcH seems to play a role in the etiology of liver cirrhosis. AcH may have a role in other pathological developments, which include brain damage, cardiomyopathy, pancreatitis, and fetal alcohol syndrome. AcH creates both unpleasant aversive reactions that protect against excessive alcohol drinking and euphoric sensations that may reinforce alcohol drinking. The protective effect of AcH may be used in future treatments that involve gene therapy with or without liver transplantation.

CONCLUSIONS

AcH plays a role in most of the actions of alcohol. The individual variability in these AcH-mediated actions will depend on the genetic polymorphism, not only for the alcohol and AcH-metabolizing enzymes but also for the target sites for AcH actions. The subtle balance between aversive and reinforcing, protecting and promoting factors will determine the overall behavioral and pathological developments.

Genetic polymorphism of alcohol dehydrogenase in europeans: the ADH2*2 allele decreases the risk for alcoholism and is associated with ADH3*1

Polymorphism at the ADH2 and ADH3 loci of alcohol dehydrogenase (ADH) has been shown to have an effect on the predisposition to alcoholism in Asian individuals. However, the results are not conclusive for white individuals. We have analyzed the ADH genotype of 876 white individuals from Spain (n = 251), France (n = 160), Germany (n = 184), Sweden (n = 88), and Poland (n = 193). Peripheral blood samples from healthy controls and groups of patients with viral cirrhosis and alcohol-induced cirrhosis, as well as alcoholics with no liver disease, were collected on filter paper. Genotyping of the ADH2 and ADH3 loci was performed using polymerase chain reaction-restriction fragment length polymorphism methods on white cell DNA. In healthy controls, ADH2*2 frequencies ranged from 0% (France) to 5.4% (Spain), whereas ADH3*1 frequencies ranged from 47. 6% (Germany) to 62.5% (Sweden). Statistically significant differences were not found, however, between controls from different countries, nor between patients with alcoholism and/or liver disease. When all individuals were grouped in nonalcoholics (n = 451) and alcoholics (n = 425), ADH2*2 frequency was higher in nonalcoholics (3.8%) than in alcoholics (1.3%) (P =.0016), whereas the ADH3 alleles did not show differences. Linkage disequilibrium was found between ADH2 and ADH3, resulting in an association of the alleles ADH2*2 and ADH3*1, both coding for the most active enzymatic forms. In conclusion, the ADH2*2 allele decreases the risk for alcoholism, whereas the ADH2*2 and ADH3*1 alleles are found to be associated in the European population.

Association of D2 dopamine receptor and alcohol dehydrogenase 2 genes with Polynesian alcoholics

Alleles of the D2 dopamine receptor (DRD2) and the alcohol dehydrogenase 2 (ADH2) genes were determined in 69 French Polynesian alcoholic patients and 57 controls matched for racial origin. Three racial groups were studied: pure Polynesians (PP), Polynesians mixed with Caucasian (PCA) ancestry and Polynesians mixed with Chinese (PCH) ancestry. DRD2 A1 allele frequencies in the alcoholics compared to their controls in these groups were: PP,.26 vs.32 (P =. 69); PCA,.44 vs.35 (P =.46); PCH,.40 vs 0.39 (P =.88). ADH2 1 allele frequencies in alcoholics compared to their controls groups were: PP, .56 vs.62 (P =.66); PCA,.75 vs.56 (P =.09); PCH,.78 vs.32 (P =.009). In the PCA group, the combination of the DRD2 A1 genotypes and the ADH2 1 homozygotes was strongly associated with alcoholism (P =. 0027). This preliminary study shows the importance of ascertaining racial ancestry in molecular genetic association studies. Moreover, it suggests that a combination of genes are involved in susceptibility to the development of alcoholism.

Relationship between alcohol drinking, ADH2 and ALDH2 genotypes, and risk for hepatocellular carcinoma in Japanese

The polymorphism in the ALDH2 gene plays a central role in Asian alcohol hypersensitivity and has been associated with the risk for esophageal cancer. In the present study, we attempted to examine associations between the ADH2 and ALDH2 polymorphisms, alcohol drinking and hepatocellular carcinoma (HCC) development in a case-control study in Japan. One hundred and two patients with HCC (85 males and 17 females) and 125 control subjects (101 males and 24 females) were enrolled in the study. Higher cumulative amounts of alcohol consumption (drink-years of > or = 40 drinks/day x year) showed a significant association with HCC development (odds ratio, OR = 2.7; 95% CI = 1.3-5.5, adjusted for age and smoking). By contrast, we could find no association of the ALDH2 genotypes with HCC development (adjusted OR for ALDH2*1/*2 = 1.1; 95% CI = 0.6-2.1). Likewise, the ADH2 genotypes were not associated with HCC development (adjusted OR for ADH2*2/*2 = 0.8; 95% CI = 0.5-1.5). The present results do not support a contribution of acetaldehyde, an active metabolite of ethanol, to HCC development and rather indicate a direct involvement of ethanol in hepatocarcinogenesis.

Alcohol and aldehyde dehydrogenase gene polymorphisms influence susceptibility to esophageal cancer in Japanese alcoholics

BACKGROUND

Studies have consistently demonstrated that inactive aldehyde dehydrogenase-2 (ALDH2), encoded by ALDH2*1/2*2, is closely associated with alcohol-related carcinogenesis. Recently, the contributions of alcohol dehydrogenase-2 (ADH2) polymorphism to alcoholism, esophageal cancer, and the flushing response have also been described.

METHODS

To determine the effects of ALDH2 and ADH2 genotypes in genetically based cancer susceptibility, lymphocyte DNA samples from 668 Japanese alcoholic men more than 40 years of age (91 with and 577 without esophageal cancer) were genotyped and the results were expressed as odds ratios (ORs). This study also tested 82 of the alcoholics with esophageal cancer to determine whether cancer susceptibility is associated with patients' responses to simple questions about current or former flushing after drinking a glass of beer.

RESULTS

The frequencies of ADH2*1/2*1 and ALDH2*1/2*2 were significantly higher in alcoholics with, than in those without, esophageal cancer (0.473 vs. 0.289 and 0.560 vs. 0.099, respectively). After adjustment for drinking and smoking, the analysis showed significantly increased cancer risk for alcoholics with either ADH2*1/2*I (OR = 2.03) or ALDH2*1/2*2 (OR = 12.76). For those having ADH2*1/2*1 combined with ALDH2*1/2*2, the esophageal cancer risk was enhanced in a multiplicative fashion (OR = 27.66). Responses to flushing questions showed that only 47.8% of the ALDH2*1/2*2 heterozygotes with ADH2*1/ 2*1, compared with 92.3% of those with ALDH2*1/2*2 and the ADH2*2 allele, reported current or former flushing. Genotyping showed that for alcoholics who reported ever flushing, the questionnaire was 71.4% correct in identifying ALDH2*1/2*2 and 87.9% correct in identifying ALDH2*1/2*1.

CONCLUSION

Japanese alcoholics can be divided into cancer susceptibility groups on the basis of their combined ADH2 and ALDH2 genotypes. The flushing questionnaire can predict high risk ALDH2*1/2*2 fairly accurately in persons with ADH2*2 allele, but a reliable screening procedure for the highest risk gene combination (ADH2*1/2*1 and ALDH2*1/2*2) will require further investigation.

Development of a questionnaire method to discriminate between typical and atypical genotypes of low Km aldehyde dehydrogenase in a Japanese population

Nearly half of all Orientals exhibit aversive symptoms, such as "Oriental flushing" or palpitation, during alcohol consumption. This high alcohol sensitivity among Orientals has been attributed to a highly prevalent polymorphism in low Km aldehyde dehydrogenase (ALDH2). In the present study, we attempted to develop a reliable questionnaire method to probe the frequency of alcohol drinking-related symptoms to estimate the ALDH2 genotype. Four-hundred twenty-four male and 100 female workers provided blood samples for polymerase chain reaction analysis and completed the questionnaire. We performed a stepwise logistic regression analysis to discriminate between the typical homozygote (ALDH2*1/*1) and the atypical heterozygote (ALDH2*1/*2) in male subjects. Because of the limitation in the sample size for ALDH2*2/*2, this genotype was not included in the analysis. Results revealed that only three symptoms (facial flushing, flushing elsewhere, and palpitation) were enough to correctly predict the ALDH2 genotypes in approximately 89% of all subjects. The present questionnaire method (ALcohol Sensitivity screening Test; ALST) takes a little time and effort for the genotype determination, and may be especially useful in epidemiological studies with a large sample size or with subjects from whom DNA samples are not available.

Acute reactions to alcohol

Where the experience of alcohol is unpleasant because of adverse reactions to small amounts, alcohol consumption is likely to be low and alcohol dependence rare. This is shown by many studies of Asian subjects who experience the alcohol flush reaction (AFR) due to inherited aldehyde dehydrogenase (ALDH) deficiency. Alcohol reactions are less common and on average less severe in non-Asian subjects, but they do occur and can affect alcohol consumption. Information about alcohol reactions and their consequences in Europeans is reviewed, and such reactions are compared with those caused by mitochondrial ALDH deficiency in Asians.