People with the ‘drunken’ gene are more likely to get drunk quickly but because they cannot take their alcohol are actually less likely to become alcoholics.
The gene, named CYP2E1, provides the coded instructions for making an enzyme that breaks down alcohol, Clinical and Experimental Research journal reported.
The US researchers believe that 10% to 20% of the population possess a particular version of the gene that causes them to get drunk easily.
The first few drinks during a night out will leave these individuals feeling more inebriated than their friends. They are therefore more likely to stop drinking earlier.
Ultimately, people could be given CYP2E1-like drugs to make them more sensitive to alcohol – not to get them drunk more quickly, but to put them off drinking to inebriation, the Alcoholism, said the researchers.
Lead researcher Professor Kirk Wilhelmsen said: “Obviously we are a long way off having a treatment, but the gene we have found tells us a lot about how alcohol affects the brain.”
Scientists in the US investigated the genetics of 237 college student siblings who had one alcohol-dependent parent but were not alcoholics themselves.
They homed in on an end region of chromosome 10 where the CYP2E1 gene resides. Participants’ response to drinking was linked to their genetic make-up.
The US researchers gave the students a mixture of grain alcohol and soda that was equivalent to about three average alcoholic drinks. At regular intervals they were then asked whether they felt drunk, sober, sleepy or awake.
Professor Wilhelmsen, the senior study author from the University of North Carolina, said: “We have found a gene that protects against alcoholism, and on top of that, has a very strong effect.”
“But alcoholism is a very complex disease, and there are lots of complicated reasons why people drink. This may be just one of the reasons,” he added.
CYP2E1’s effect on sobriety is probably due to the fact that it is not active in the liver, but the brain. It generates destructive molecules called free radicals, which can damage sensitive structures such as brain cells.
“It turns out that a specific version of CYP2E1 makes people more sensitive to alcohol, and we are now exploring whether it is because it generates more of these free radicals,” said Prof Wilhelmsen.
In another study published in the same journal, scientists found evidence that the brain’s ability to become addicted to alcohol depends on genetic make-up. The research, conducted on mice, showed changes associated with addiction in animals lacking a key “feel good” gene.
“This study shows that the effects of chronic alcohol consumption on brain chemistry are critically influenced by an individual’s pre-existing genetic make-up,” said the lead researcher Panayotis Thanos, from the Brookhaven National Laboratory in New York.
Don Shenker, of the charity Alcohol Concern, said that, in most cases, alcohol abuse stemmed from social problems, with alcohol used as a prop. And professor Colin Drummond, an expert in addiction at London’s Institute of Psychiatry, said it was likely to be combination of genes and environment.
“It is well recognised that alcohol dependence runs in families,” he said. He said research suggests having an alcoholic parent quadruples a person’s risk of developing a drinking problem. [via Daily Telegraph (UK) and BBC]