Simultaneous genotyping of alcohol dehydrogenase 2 and aldehyde dehydrogenase 2 by single‐strand conformation polymorphism analysis

Alcohol dehydrogenase (ADH; EC 1.1.1.1) and aldehyde dehydrogenase (ALDH; EC 1.2.1.3) have important roles in the elimination of ingested ethanol. These enzymes have polymorphisms resulting from single-point mutations that cause kinetic differences in their respective enzyme activities. Simultaneous observation of these enzymes would be useful in investigating the association between these enzyme polymorphisms and alcohol-related problems. In this study amplified genomic DNA was amplified from nail clippings with two sets of primers for ADH2 and ALDH2 genes, respectively, in a micro test tube and the accuracy of the amplification was verified by direct sequencing. The PCR products were separated into four distinct bands by single-strand conformation polymorphism analysis. This genotyping method is fast, accurate. reliable and inexpensive, and requires the same amount of template DNA as non-simultaneous methods. In other words, the required amount of template DNA for this method is only half that required for the separate genotyping of ADH2 and ALDH2.

Alcohol drinking frequency is more directly associated with alcohol use disorder than alcohol metabolizing enzymes among male Japanese

The development of alcohol use disorder (AUD) is related to various social, economic, cultural, environmental and hereditary factors. Several potential risk factors have been proposed for AUD in addition to alcohol consumption, including alcohol dehydrogenase2 (ADH2), acetaldehyde dehydrogenase2 (ALDH2), marital status, educational, occupational or past medical history (e.g. diabetes mellitus, hypertension, lung, digestive tract, or chronic liver disease) or smoking habits. The present study was performed to investigate the relationship between the aforementioned potential risk factors and AUD in Japan. A case-control study was performed on 153 male Japanese AUD patients and age-, gender-, or other confounder-matched controls to investigate the relation multivariately between ADH2, ALDH2 or alcohol drinking and AUD. Genomic DNA were extracted from nail clippings by the guanidium method, and genotyping of ADH2 and ALDH2 were performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. Univariate analyses by the conditional logistic regression model revealed statistically significant odds ratios due to ADH2*1/1 genotype, ALDH2*1/1 genotype, middle school as the final school attended, longest occupations as farmers, fishermen, craftsmen, miners, production process or construction workers, and past histories of chronic liver disease and AUD. However, multivariate analyses under a hierarchically well-formulated model strategy with interaction and confounding assessment indicated that (i) heavy alcohol intake was a significant risk factor (odds ratio per 1.0 g of daily ethanol intake; 1.096, 95% confidence interval; 1.026-1.171) for developing AUD after adjusting for other confounders; and (ii) ADH2*1/1 genotype and ALDH2*1/1 genotype were not risk factors after adjusting for daily ethanol intake and other confounders. The present study shows that AUD was more directly and strongly associated with alcohol drinking than with alcohol metabolizing enzymes among male Japanese.

Alcohol dehydrogenase-2 and aldehyde dehydrogenase-2 genotypes and male alcohol use disorders in Khon Kaen, north-east Thailand

A case-control study on the relationship between alcohol dehydrogenase-2 (ADH2), aldehyde dehydrogenase-2 (ALDH2) and male probable alcohol use disorders (AUD) was performed in Khon Kaen, north-east Thailand. One hundred and fifty-three paired cases (probable AUD) and controls (non-probable AUD) were sampled from villagers aged 18-65 years using the modified Michigan Alcoholism Screening Test - Thai version, controls being matched for gender, age (+/- 4 years) and village. All of the cases and 86.9% of the controls were current drinkers. The percentage of ADH2*1/1 among cases was 47.1%, being significantly larger than the 29.4% among controls, and yielding a univariate odds ratio (OR) of 2.421* (95% confidence interval (CI) = 1.419-4.132) for developing probable AUD. The ALDH2*1/1 proportion among cases, 92.8%, was comparable to the 92.2% among controls, yielding a univariate OR of 1.100 (95%CI = 0.757-1.599). Multivariate analysis based on a conditional logistic regression model and a hierarchically well-formulated model strategy revealed that: (i) the OR of developing probable AUD due to 1 g increment of daily ethanol drinking was 1.110* among farmers (95%CI = 1.054-1.170); (ii) OR due to 1 g increment of daily ethanol drinking was 1.329* among non-farmers (95%CI = 1.109-1.593); (iii) OR due to either ADH2*1/1 or ALDH2*1/1 was insignificant; and (iv) the daily amount of smoking is independently associated with probable AUD. The present findings suggest that one of the genetic factors that may be related to probable AUD among Thai males living in the north-east is the ADH2 gene.

Identification of N-acetyltransferase 2 and CYP2C19 genotypes for hair, buccal cell swabs, or fingernails compared with blood

Genotyping of polymorphic drug metabolizing enzymes may be useful to estimate the blood concentration, efficacy, and toxicity of drugs before administration. Blood samples are most generally used for genotyping; however, sampling is invasive and complicated by handling and transport. Therefore, the authors developed genotyping methods using nonblood specimens, and then each genotype was compared with that from blood. Healthy Japanese volunteers provided hairs (n = 50), buccal cell swabs (n = 50), and fingernails (n = 30) for N-acetyltransferase 2 and CYP2C19 genotyping. Recovery of genomic DNA from each nonblood specimen was lower than that from 0.5 mL blood. Using a modification of the DNA extraction and polymerase chain reaction amplification method, genotypes were diagnosed without failure, even for those with very low levels of DNA. Both genotypes from these specimens completely matched the genotypes from the blood of the same subject. These nonblood specimens can be convenient, accessible, and economical alternatives to blood as a source of DNA for genotyping.