Scientists have discovered a gene variant that is associated with a person's response to alcohol and may help protect one against alcoholism.
Researchers from the University of North Carolina at Chapel Hill School of Medicine found a gene variant called CYP2E1 and for the ten to twenty percent of people that possess this variant, the first few drinks leave them feeling more inebriated than the rest of the human population.
The discovery of CYP2E1's role hints at a new mechanism of how people perceive alcohol, and further, how alcohol affects the brain.
"We have found a gene that protects against alcoholism, and on top of that, has a very strong effect. Alcoholism is a very complex disease, and there are lots of complicated reasons why people drink. This may be just one of the reasons," said Kirk Wilhelmsen, senior study author.
The research takes a specific phenotype - the way people feel after consuming alcohol - and uses it to dissect why some people develop alcoholism and some do not.
For research, Wilhelmsen and his colleagues gathered hundreds of pairs of siblings, all college-age, and all with at least one parent who was an alcoholic. First, the participants were given a mixture of grain alcohol and soda that was equivalent to about three drinks. Then they were asked at regular intervals to answer a number of questions describing how the alcohol made them feel.
The researchers then conducted time-honoured genetic analyses called linkage and association to hone in on the gene region that appeared to influence how the students perceived alcohol.
The CYP2E1 gene has long held the interest of researchers interested in alcoholism, because it encodes an enzyme that can metabolise alcohol.
"It turns out that a specific version or allele of CYP2E1 makes people more sensitive to alcohol, and we are now exploring whether it is because it generates more of these free radicals. This finding is interesting because it hints at a totally new mechanism of how we perceive alcohol when we drink. The conventional model basically says that alcohol affects how neurotransmitters, the molecules that communicate between neurons, do their job. But our findings suggest it is even more complex than that," explained Wilhelmsen.
In the future, drugs that induce CYP2E1 could be used to make people more sensitive to alcohol before they've taken their first drink, or even to help sober them up when they've had one too many.
The study will appear in the journal Alcoholism: Clinical and Experimental Research.