Excessive alcohol-drinking gene mutation discovered

A gene that regulates alcohol consumption - and, when faulty, can cause excessive drinking - has been discovered by researchers.

Researchers have identified the mutated gene Gabrb1, which changes alcohol preference so strongly that mice carrying either of two single base-pair point mutations in this gene preferred drinking alcohol (10% ethanol v/v - about the strength of wine) over water.

A team led by Professor Howard Thomas from Imperial College London introduced subtle mutations into the genetic code at random throughout the genome and tested mice for alcohol preference. The study showed that mice carrying this mutation were willing to work for the alcohol and continued to drink consistently more than normal mice over long periods of time, consuming alcohol for almost 85% of their daily fluid intake.

The cause of this excessive drinking was tracked down to a single point mutation in the Gabrb1 gene, which codes for the beta 1 subunit, an important component of the GABA_A receptor in the brain. It’s this receptor that responds to the brain’s most important chemical messenger (GABA), in charge of regulating brain activity. Researchers found that the gene mutation caused the receptor to activate spontaneously even when the usual GABA trigger was not present.

Dr Quentin Anstee, Consultant Hepatologist at Newcastle University and joint lead author, said: “It’s amazing to think that a small change in the code for just one gene can have such profound effects on complex behaviours like alcohol consumption.

“We are continuing our work to establish whether the gene has a similar influence in humans, though we know that, in people, alcoholism is much more complicated as environmental factors come into play. But there is the real potential for this to guide development of better treatments for alcoholism in the future.”