Scientists edge toward finding genes linked to alcoholism


Scientists edge toward finding genes linked to alcoholism


The closer science comes to unravelling the genetic aspects of alcoholism, the more emphasis is being placed on the importance of environmental factors and individuals' ability to avoid their genetic destiny.

That was one of the main messages from a session on the Collaborative Study on the Genetics of Alcoholism (COGA) at the American Society of Addiction Medicine annual meeting in San Diego this April. COGA was launched seven years ago by the U.S. National Institute on Alcohol Abuse and Alcoholism (NIAAA).

While far from finding the specific genes for alcoholism, COGA has already accumulated an impressive database and has begun to target specific "books" in the library which is the human genome.

Dr. Enoch Gordis, chair of the session and director of NIAAA, stressed in his introduction, "nobody is asserting alcoholism is only a genetic disease.

We're looking for the portion of vulnerability to alcoholism which is inherited," he said.

Gordis said the genetics of alcoholism could be likened somewhat to the genetics of obesity, where even in a person with a genetic susceptibility to the disease, the condition is not guaranteed on exposure to the addictive agent, be it alcohol or food.

Even when the genes which govern alcoholism are unravelled, he said, the findings will not "absolve" someone with the gene from doing everything they can to not become addicted.

Dr. Howard Edenberg, professor of biochemistry at Indiana University School of Medicine, Indianapolis, said he suspects the gene - environment interaction will prove "crucial" as the genetics of alcoholism are better mapped.

We have to remember and we have to remind our patients and the public [that] the fact the risk is in part genetic does not mean it's inevitable," he said.

As for finding the genes themselves, Edenberg said, COGA is still at the early stages although some intriguing work has begun to suggest chromosomal regions appear linked with alcoholism.

Dr. Alison Goate, associate professor of genetics in psychiatry at Washington University, St. Louis, said linkage studies using COGA families have shown areas of chromosome one and seven are most strongly associated with alcoholism, while an area of chromosome four appears to have a protective effect.

COGA focuses on collecting DNA information from individuals of families with many alcohol - dependent members. As of January 1997, COGA has 895 families (4,715 individuals) in which at least three family members are alcohol - dependent, said Dr. Henri Begleiter, head of COGA and professor of psychiatry at the State University of New York. Of these, there are 332 families with at least five alcohol - dependent family members. Overall, with control subjects from families with no alcoholic members, COGA has information on about 112,000 people.

This is a mammoth project," Begleiter noted. Bolstering the COGA work have been new studies involving children of alcoholics, twins and adoptees, which confirm the inherited nature of alcohol dependence in some cases.

Dr. Marc Schuckit, professor of psychiatry at the University of California, San Diego Medical School, said measures should concentrate on children of alcoholics who choose to drink and are proud of how well they can hold their liquor, because this indicates they are more susceptible. In addition, he said, his data suggest those who are easily bored and more impulsive may also be at higher risk.