Autism Gene Linked to Alcoholism

Summary
A meta-analysis was recently conducted in London to evaluate the role of hereditary factors in developing the drinking habit. The researchers looked for the association of a specific gene called “Autism Susceptibility Candidate 2 (AUTS2) Gene” with alcoholism. In addition, they looked for the same gene in specific parts of the brain, especially the frontal lobe that is involved in the craving for alcohol. To assess this, they obtained brain tissues after the postmortem examination. They found that there was a significant association between the expression of the AUTS2 gene and alcohol consumption.

Introduction
Many of the earlier studies have shown that alcoholism is an inherited habit. But very few studies have been done so far to identify the genes that are responsible for this. In the present study, the researchers aimed to evaluate the role of AUTS2 gene with alcohol consumption. Almost 9 percent of all diseases in developing countries are the result of alcohol consumption. It is estimated that about 40 percent of alcoholics have a family background of alcohol addiction. A genetic association study would help in unraveling the basis of such a hereditary association. This knowledge may help in the treatment of people who want to abstain from the use of alcohol.

Methodology

  • “Genome wide association study” data of 26,316 participants in 12 European-ancestry populations were collected. The amount of alcohol that they consumed per day was also measured.
  • The presence of AUTS2 gene was examined in all of them using various techniques such as Affymetrix, Illumina, Perlegen, etc.
  • Postmortem samples of human brain tissues were obtained from 27 alcoholics who had committed suicide. 69 control samples were also collected from individuals who were not alcoholics, and had died because of heart ailments. Tissue from the frontal portion of brain was analyzed in both groups, to examine the expression of AUTS2 gene, by using a technique called Bio GPS.
  • There are various mouse models which differ in their alcohol consumptions. Experiments were done on the mice, to note the expression of AUTS2 gene in their brain.

Results

  • The alcohol consumption among participants ranged from 0.09 to 0.24 g/day per kg in men and from 0.02 to 0.16 g/day per kg in women.
  • A statistically significant association was noted between the amounts of alcohol consumption and AUTS2 gene expression.
  • Expression of AUTS2 gene was found to be high in brain samples of alcoholics.
  • Mice experiments showed that AUTS2 gene expression was high in the brain tissue of “Alcohol-Preferring” model of mice.

Conclusion
The present study has identified a significant association between AUTS2 gene and alcohol consumption, although the function of AUTS2 gene is yet to be understood. This gene expresses especially in the neurons of the frontal portion of the brain, which influences alcohol impulsivity.  “Alcohol-Preferring” model of mice showed high expression of AUTS2 gene. Increased expression of this gene is observed in the human psychiatric disorder, Attention Deficit Hyperactivity Disorder, which also involves impulsive behavior. Having identified the gene, identifying its function will help understand the basis of development of hereditary alcoholism. This, in turn, will help in the discovery of therapeutic agents which will help in preventing development of alcoholism in genetically susceptible individuals.

For More Information:
Genetic Association Study to Identify Role of AUTS2 Gene in the Regulation of Alcohol Consumption
PNAS Early Edition, 2011
By Gunter Schumann; Lachlan J Coin
From the King’s College, London, United Kingdom, and the Imperial College London, London, United Kingdom

*FYI Living Lab Reports Are Summaries of the Original Research.

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