"The genes of alcoholism"
Variations in human genes responsible for alcohol cravings have been found
British scientists have found that genetic predisposition plays a significant role in the occurrence of alcohol dependence. The study revealed certain gene variations in drinkers. The results are published in the journal Science Advances (Thompson et al., Functional validity, role, and implications of heavy alcohol consumption genetic loci).
Propensity to alcoholism is considered to be the result of a complex interaction between genetic and non-genetic risk factors. The fact that the craving for alcohol is associated, among other things, with a genetic predisposition is confirmed by numerous facts on the examples of families with separated twins, adopted children and similar behavior towards alcohol of direct relatives, regardless of their living conditions and life circumstances.
In an attempt to identify specific genes responsible for alcohol addiction, British scientists led by Andrew Thompson and Munir Pirmohamed from the University of Liverpool conducted a genome-wide association study (GWAS) using data from the UK Biobank (125,249 participants) and the American GERA database (47,967 participants).
All the study participants were adults – from 40 to 69 years old. Each of them was asked to name the approximate number of glasses of wine or mugs of beer they drink in a week. The researchers focused on the British recommendations on alcohol consumption, according to which the problem group includes men and women who consume more than 5 and 3.5 bottles of wine or more than 25 and 15 cans of beer, respectively, weekly.
The GWAS method allows you to search for small variations in genes in the human DNA (genome), called single-nucleotide polymorphisms. Each person's genome carries millions of variations, but if specific variations are more common in people with a certain disease than in people without the disease, this may indicate a genetic cause of the disease.
After analyzing the genome of the volunteers, the scientists found six gene variations that were present in all participants falling into the problem group. Some of these variations have already appeared in other studies related to the study of hereditary dependencies.
For example, the DRD2 and KLB genes are associated with a sense of pleasure and reward that occurs when consuming not only alcohol, but also sweets. A low level of the ADH1B gene, which encodes enzymes that break down alcohol, is also one of the signs of a predisposition to alcohol. In people with low levels of ADH1B, the process of alcohol metabolism slows down, and they can drink alcohol for a long time without feeling signs of alcohol intoxication.
To test the results, the scientists conducted an experiment on model worms, in which they turned off the identified genes. At the same time, the craving for alcohol has noticeably decreased in all worms. This confirms the conclusion of scientists about the important role of the genetic factor in the occurrence of alcohol dependence.
"When studying the biological consequences of gene variations, we found evidence pointing to several common pathways associated with various types of compulsive behavior and addictions, in addition to alcohol consumption," Andrew Thompson said in a university press release. – We are currently working with samples of patients with other addictions to identify the similarity of their genetic characteristics with those who abuse alcoholic beverages. We want to test the hypothesis that the genes identified in this work are involved in common pathways associated with different types of addictions."
Scientists hope that the results of their research will serve as a basis for the development of new methods of treatment of alcohol and other types of addictions.
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