Genetic Polymorphism of Alcohol Dehydrogenase 2 (ADH1B) in Association with Alcohol Consumption in Nepalese Population

Author(s): Rabina Ramtel, Vijay Kumar Sharma, Rahul Pathak, Binod Kumar Yadav, Eans Tara Tuladhar, Mithileshwor Raut, Aseem Bhattarai, Raju Kumar Dubey, Apeksha Niraula, Alisha Sapkota, Hari Sharan Makaju, Anant Neupane, Pujan KC, Kiran Poudel

Background and Objective: Alcohol is metabolized by the alcohol dehydrogenase (ADH) enzyme system. ADH1B is mostly ethnic and race dependent. Functional polymorphisms within ADH1B gene, alters the enzymatic metabolism of ethanol consequently making a difference in the alcohol elimination rates. Thus, it’s necessary to assess SNP of ADH1B gene in subjects consuming alcohol to explore their genotypic influence on alcohol metabolism. This study was aimed to determine the genetic polymorphisms of ADH1B (Arg47His) in patients with chronic liver disease due to alcohol consumption and healthy non-alcoholic subjects without liver disease, it’s impact on duration of alcohol consumption, and to observe the distribution of its polymorphic variants within different ethnic groups encountered during the study.

Methods and Methodology: A total of 82 EDTA blood samples were taken from alcoholic and non-alcoholic subjects. Molecular analysis was done for detection of ADH1B polymorphism by PCR-CTPP method and products were visualized by 1.5% agarose gel electrophoresis.

Results: Overall, the homozygous form i.e. ADH1B*1/*1 genotype have the highest prevalence rate. The frequency of ADH1B*1 allele was 97.55% and ADH1B*2 allele was 2.45%. Similarly, ADH1B*1/*1 genotype was found to be highest in aadibasi/janajati ethnicity. Furthermore, individuals consuming alcohol for a longer duration have ADH1B*1/*1 genotype.

Conclusion: It can be concluded that the presence of ADH1B*1/*1, ADH1B*1/*2 and ADH1B*2/*2 genotype alters alcohol metabolism, its consumption and tolerance. The presence of ADH1B*1/*1 genotype increases the tolerance towards alcohol and makes individual more liable to alcoholism preceding the onset of alcohol use disorders. Thus, result might indicate the presence of ADH1B*2 allele to be protective against alcoholism and its subsequent consequence.