Alcoholism genes

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Although alcohol is widely consumed, excessive use can lead to serious physical, psychological, and social problems, as well as contribute to various diseases. Alcoholism, also known as alcohol dependence or alcohol use disorders, is a harmful pattern of excessive drinking that can result in severe issues. Research suggests that alcoholism is a complex genetic disease, with numerous genes affecting the risk of developing it. Some of these genes, such as ADH1B and ALDH2, which are involved in alcohol metabolism, have been identified as having the most significant impact on alcoholism risk. Other genes, including GABRA2, CHRM2, KCNJ6, and AUTS2, have also been found to affect the risk of alcoholism or related traits. As more extensive studies are conducted and more genetic variants are analyzed, a more comprehensive understanding of the genes and pathways that influence alcoholism risk will emerge.

Alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2), which play a crucial role in alcohol metabolism, are the genes that have the most significant impact on the risk of alcoholism and alcohol consumption. While alcohol is primarily metabolized in the liver, some metabolism also occurs in the upper gastrointestinal tract and stomach. The initial stage of ethanol metabolism involves oxidation to acetaldehyde, which is primarily catalyzed by ADHs. There are seven closely related ADHs clustered on chromosome 4.

The linked region was analyzed for SNP genotyping, specifically in candidate genes such as the GABAA receptor genes. Within the GABRA2 gene, a group of SNPs that were highly correlated with each other were found to be associated with alcohol dependence and contributed to the observed linkage finding. This association has been confirmed in various samples of European and African ancestry, with the strongest correlation found in alcoholics with early onset or comorbid drug dependence. Additionally, evidence suggests that the association may extend beyond GABRA2 to include the adjacent GABRG1 gene.

In a linkage study followed by genotyping candidate genes in the region, the CHRM2 gene, which codes for the muscarinic cholinergic receptor 2, was found to be linked to alcohol dependence. This finding has been replicated by other groups and is particularly strong in individuals with early onset or comorbid drug dependence, similar to the GABRA2 gene. Studies have also focused on the electrophysiological endophenotype of this gene, mirroring the approach taken with GABRA2.

The study initially examined the genome of male inpatients in Germany, and then conducted targeted genotyping of the top SNPs. The joint analysis revealed that two SNPs in the 3' flanking region of PECR, a member of the short-chain dehydrogenase family of enzymes, were associated with alcohol dependence. PECR is located within broad linkage peaks for various alcohol-related traits, such as alcoholism, comorbid alcoholism and depression, level of response to alcohol68, and amplitude of the P3(00) response.

Certain genes could potentially heighten the vulnerability to addictions overall. Through a staged meta-analysis, a study delved into the co-occurrence of alcohol and nicotine dependence and identified genome-wide indications of a correlation with SNPs that cover a section on chromosome 5, encompassing IPO11 (importin 11) and HTR1A (5-hydroxytryptamine (serotonin) receptor 1A, G protein-coupled).

The examination of RNA expression in lymphoblastoid cell lines indicated that the SNPs present in this particular area on chromosome 5 had regulatory effects on the expression of HTR1A or IPO11 through cis-acting mechanisms.

According to the researchers, conducting larger studies could aid in distinguishing the genetic factors contributing to alcohol addiction.

Follow the link of the selected polymorphism to read a brief description of how the selected polymorphism affects Alcohol dependence and see a list of existing studies.

SNP polymorphisms related to the topic Alcohol dependence: