Discovery May Point the Way to Treatments for Binge Drinking

An international consortium of scientists led by researchers at Imperial College and King's College in London found that people who have a relatively rare version of a gene called AUTS2 tend to drink about 5 per cent less than people who have the more common version of the gene. The gene seems to make alcohol consumption less rewarding by causing the brains of people who have this gene to make less of the reward chemical dopamine than the brains of people who have the more common gene.The effect of the gene is small, but it is only the second gene known to have an effect on how much people drink. The other gene, which encodes the proteins used to make the enzyme that breaks down alcohol in the liver, causes people of some ethnic groups (especially East Asians) to get drunker faster because their bodies do not detoxify the alcohol.Researchers in the international study analyzed DNA from 26,316 donors to look for genetic markers that might explain the amount of alcohol the donors listed on surveys. The researchers then checked their findings by analyzing another 21,185 DNA donors and surveying their drinking habits. The conclusion of the study was that a variation in the AUTS2 gene that makes more of a protein that leads to the creation of dopamine was also associated with lower, although only slightly lower, levels of alcohol consumption.The scientists then examined the working of the AUTS2 gene in 96 samples of brain tissue donated by families of suicide victims and accidental death victims after their autopsies. They found that different types of the gene responded to alcohol in different ways, and that these variations were consistent with what they had observed in a similar gene in lab rats and Drosophila, the gnats so often used in genetic studies.The AUTS2 gene was previously investigated as a possible link to autism, mental retardation, schizophrenia, Tourette's syndrome, restless legs syndrome, and attention deficit hyperactivity disorder (ADHD). In these conditions, the gene causes problems by appearing in multiple copies or on the wrong chromosomes, showing up where it should not be in the nucleus of the cell, so it is not switched on and turned off normally.With regard to alcohol consumption, however, the question is whether AUTS2 is more active or less active. And since the activity of a gene is expressed in proteins, medications that encourage the formation of proteins may stop the production of the feel-good chemicals that are triggered by binge drinking, only without the binge drinking.