Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.1 (alcohol dehydrogenase)
 9,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Little is known about factors determining individual susceptibility to the physical complications of alcohol abuse but genetically determined differences in ethanol metabolism may be important. The oxidative metabolism of alcohol is catalyzed by alcohol and aldehyde dehydrogenase. Polymorphisms have been observed at two of the five loci encoding alcohol dehydrogenase subunits: ADH2 (producing three beta subunits) and ADH3 (producing two tau subunits) and also at the locus encoding the metabolically important form of aldehyde dehydrogenase, ALDH2. We have compared ADH2, ADH3 and ALDH2 allele frequencies in patients with alcohol-related cirrhosis (n = 59) and chronic pancreatitis (n = 13) with 79 local healthy control subjects. The different alleles were detected with allele-specific oligonucleotide probes after amplification of leukocyte DNA by the polymerase chain reaction. All patients and all but one control subject were homozygous ADH2*1, encoding the beta 1 subunit. No ADH2*3 alleles were detected. All 34 patients and 39 control subjects tested were homozygous ALDH2*1 encoding the active enzyme. ADH3 allele frequencies were different in patients and control subjects. ADH3*1 frequency: control subjects, 55.1%; cirrhotic patients, 62.7%; chronic pancreatitis patients, 65.4%. The difference between the patient groups combined and the control subjects was significant (p less than 0.05; G-test of Sokal and Rohlf) if it was assumed that the allele frequency in our control population was a reasonable estimate of our local population allele frequency. These results suggest that genetically determined differences in alcohol metabolism may, in part, explain predisposition to alcohol-related end-organ damage.
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PMID:Investigation of the role of polymorphisms at the alcohol and aldehyde dehydrogenase loci in genetic predisposition to alcohol-related end-organ damage. 193 84

The class I hepatic alcohol dehydrogenases (ADHs) are primarily responsible for ethanol metabolism in humans. Genetic polymorphism at the ADH2 locus results in the inheritance of isozymes of strikingly different catalytic properties. The most common ADH2 allele, ADH2*1, encodes the low K(m) isozyme subunit beta 1. The ADH2*3 allele encodes a high-activity isozyme subunit of alcohol dehydrogenase, beta 3, identified in approximately 25% of African-Americans. The Vmax of beta 3 beta 3-ADH is 30 times greater than that of the beta 1 beta 1-ADH. Therefore, we hypothesized that the rate of ethanol metabolism, an important factor in the toxicity of ethanol, in persons with beta 3-containing ADH, either beta 3 beta 3- or beta 1 beta 3-ADH, would be faster than that of persons with only beta 1 beta 1-ADH. We tested this hypothesis with ethanol administered orally to healthy, young African-Americans. Three hundred and twenty-six African-American men and women were genotyped using polymerase chain reaction amplification of their leukocyte DNA followed by hybridization with allele-specific probes. One hundred twelve volunteers, selected by genotype, received an oral dose of ethanol designed to produce a blood ethanol concentration of 80 mg/dl (0.080 g/dl), when the blood alcohol concentration-time curve was extrapolated back to time 0. Ethanol metabolic rates (beta 60s) were determined in the 112 subjects from the slope of the pseudolinear portion of the blood ethanol concentration-time curves. The mean beta 60 of African-Americans having beta 3-containing ADH isozymes had significantly faster ethanol elimination rates than those with only beta 1 beta 1-ADH isozymes. There were no significant differences in body weight, ethanol intake in the week before testing, peak breath ethanol concentration, time to peak, or volume of distribution between the genotype groups. Within each of these groups, men had lower ethanol disappearance rates than women. These results demonstrate in vivo the kinetic differences of ADH2 isozymes that may influence individual risk for the effects of ethanol.
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PMID:ADH2 gene polymorphisms are determinants of alcohol pharmacokinetics. 874 16

Considerable variation in offspring outcome is observed after intrauterine alcohol exposure. The underlying mechanism may include genetic diversity in the enzymes responsible for alcohol metabolism. Of the known genetic polymorphisms, differences at the alcohol dehydrogenase-2 locus (ADH2) are likely most critical because the resulting enzymes are >30-fold different in their kinetic constants. To test whether differences in maternal or offspring ADH2 genotype are determinants of risk for alcohol-related birth defects, maternal-infant pairs (n = 243) were enrolled on the basis of maternal alcohol intake during pregnancy and maternal ADH2 genotype. Infant outcome was measured using the Bayley Scales of Infant Development Mental Index (MDI) at 12 months of age. Drinking during pregnancy was associated with lower MDI scores but only in the offspring of mothers without an ADH2*3 allele (P < .01, analysis of variance, post hoc). The offspring of drinking women with at least one ADH2*3 allele had MDI scores similar to those of nondrinking women of either ADH2 genotype. Lower MDI scores were associated with the three-way interaction among increasing alcohol intake and maternal and offspring absence of the ADH2*3 allele (P < .01, multiple linear regression). We suggest that the protection afforded by this allele is secondary to its encoding of the high-Km/high-Vmax ADH beta3 isoenzyme, which would provide more efficient alcohol metabolism at high blood alcohol concentrations. These observations are supportive of alcohol, rather than acetaldehyde, being the more important proximate teratogen and are the first observations of a specific genetic explanation for susceptibility differences to alcohol-related birth defects.
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PMID:Alcohol dehydrogenase-2*3 allele protects against alcohol-related birth defects among African Americans. 939 81

Considerable variation in offspring outcome occurs following intrauterine ethanol exposure. The mechanism underlying this varying susceptibility may involve genetic differences in ethanol metabolism catalyzed by alcohol dehydrogenase (ADH) and cytochrome P450 2E1 (CYP2E1). A recent population study demonstrated a protective role for the ADH-beta(3) isoform, which is encoded by ADH2*3, an allele unique to African Americans. Drinking during pregnancy was associated with lower scores on the Bayley Scales of Infant Developmental Mental Index (MDI), but only in the offspring of mothers without an ADH2*3 allele. Lower MDI scores were associated with the three-way interaction among increasing ethanol intake and maternal and offspring absence of the ADH2*3 allele (p < 0.01, analysis of variance, model r(2) = 0.09). The protection afforded by this allele is likely secondary to its encoding of the high K(m), high V(max) ADH-beta3 isoenzyme, which would provide more efficient ethanol metabolism at high blood ethanol concentrations. However, the small amount of variance accounted for by the ADH2 polymorphism suggests that other genetic and/or environmental factors are also determinants of offspring risk. We recently described a 96-bp insertion polymorphism in the CYP2E1 regulatory region that is associated with enhanced CYP2E1 metabolic ability in the presence of ethanol intake or obesity, conditions associated with CYP2E1 induction (p < 0.01, both). The frequency of the insertion varies across ethnic groups, occurring in about 30% of African Americans and 7% of Caucasians (p < 0.01), and is sufficiently common to impact susceptibility to alcohol-related birth defects. Thus, genetic differences in ADH and CYP2E1 are likely determinants of offspring risk.
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PMID:ADH2 and CYP2E1 genetic polymorphisms: risk factors for alcohol-related birth defects. 1125 52

There is some evidence suggesting the allele for alcohol dehydrogenase 2*3 (ADH2*3) is associated with a protective effect against alcohol-related intrauterine growth retardation (IUGR). This study was conducted to explore the affect of the ADH2*3 allele on fetal growth. Bloodspots (n = 1016) belonging to individual infants of a subgroup of the Baltimore-Washington Infant Study (BWIS) were assayed for the presence of the ADH2*3 allele by a polymerase chain reaction (PCR)-based method. Infants genotyped for ADH2*3 were those for whom bloodspots were identified and obtained from the Maryland Newborn Screening Program. The effect of ADH2*3 and maternal alcohol consumption on intrauterine growth was explored by multivariable linear regression analysis. Twenty-six percent of the 306 blood spots belonging to African-American infants were positive for ADH2*3 (4% were homozygous and 22% were heterozygous). Only a small percentage of bloodspots for Caucasian (1.3%) were positive for the ADH2*3 allele. Consequently, further analysis concentrated on gene-exposure interactions for African-American infants. It was found that the incidence of being small-for-gestation-age (SGA) was lower for ADH2*3-positive infants (2.5% versus 8.8%; p = .08). SGA infants had elevated odds for being ADH2*3 negative (OR: 3.15, 95% C.I.: 0.70-14.26) and for being born to mothers that consumed alcohol during pregnancy (OR: 2.31, 95% C.I.: 0.77-6.91). A negative trend between maternal alcohol consumption and mean offspring birthweight was found; however, ADH2*3 did not have a significant impact on mean birthweight for infants born to mothers that drank during pregnancy. These results could be interpreted as possible support for the hypothesis that ADH2 genotype in the infant may impact risk for alcohol-related IUGR. However, this study has limitations in that it is a "nested study of convenience" and involves a relatively small number of infants born to mothers reporting moderate to heavy alcohol use during pregnancy.
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PMID:Fetal ADH2*3, maternal alcohol consumption, and fetal growth. 1516 47