For years, evidence has been accumulating that alcoholism is at least in part an inherited disease. Studies of children of alcoholics and "alcoholic" strains of lab animals have lessened the profound social stigma associated with the condition. But the 18 million admitted alcohol abusers in the U.S., from Kitty Dukakis to Darryl Strawberry, still struggle against the suspicion that people who drink excessively are weak, bad or both.
Now, for the first time, researchers say they have identified a gene that may play a role in causing alcoholism, strengthening the case that heavy drinking can be a physical disease over which an individual has little control. The finding, published last week in the Journal of the American Medical Association, "opens a window of hope" for treating alcoholics, according to co-author Dr. Ernest Noble of the University of California, Los Angeles. If the report holds up, doctors may be able to devise blood tests and treatments for alcoholism within the next ten years.
In the study, researchers examined brain samples from some 70 cadavers; half of the subjects had been alcoholics and half had not. The scientists were looking for the so-called dopamine D2 receptor gene, which affects the | capacity of cells to absorb dopamine, one of the brain's chemical transmitters. This gene was one of several suspects that researchers speculated might be an underlying cause of alcoholism. The scientists were amazed to find that the gene was present in 77% of the alcoholics and in only 28% of the nonalcoholics. The association was "surprisingly strong," said Dr. Enoch Gordis, head of the National Institute on Alcohol Abuse and Alcoholism. Exactly how the dopamine D2 receptor gene might predispose someone to alcoholism is not understood, but dopamine has been linked to craving and pleasure-seeking behavior.
The benefits from this line of research may be huge. In five years, scientists should have perfected a blood test for the gene, to help spot children at risk. And within a decade, doctors may have in hand a drug that either blocks the gene's action or controls some forms of alcoholism by altering the absorption of dopamine. Eventually, with genetic engineering, experts may find a way to eliminate altogether the suspect gene from affected individuals.
However, researchers cautioned against labeling this strand of DNA "the alcoholism gene." The gene's absence from more than 20% of the alcoholics studied suggests that additional factors are involved. Other genes, as well as an individual's upbringing and surroundings, are likely to play an important part. As evidence for an environmental influence on alcohol abuse, researchers point to the significantly higher incidence of alcoholism in men than in women, as well as the rarity of the condition in certain religious groups that discourage drinking, notably the Amish and the Mormons. Researchers also feel that last week's results need further study before doctors are convinced of the gene's role.
Still, the findings have boosted hopes. For the one in four U.S. families struck by alcoholism, the research may point to a new way to halt the deadly craving at its source.
CHART: NOT AVAILABLE
CREDIT: TOM HUTCHINS
CAPTION: LIKE FATHER . . .
Evidence that genetic factors can contribute to alcoholism: