Gene May Be Tied to Alcoholism : Research: If it is confirmed that it predisposes the carrier to the condition, it could give credence to the belief that uncontrolled drinking is a disease.

Researchers have identified for the first time a gene that may predispose some people to alcoholism, lending credence to the idea that alcoholism is a disease rather than a behavior problem and raising the possibility of new methods of prevention and treatment.

If confirmed, the discovery by researchers at UCLA and in Texas may one day make it possible to identify and warn vulnerable people--such as many of the 29 million U.S. children of alcoholics who are believed to be on average four times more likely than others to abuse alcohol.

It is unlikely, however, that a single gene will identify everyone at risk, researchers say. Because alcoholism manifests itself differently in different people, they say, other genes may be involved, as well as psychological and social factors.

“It adds one bit of evidence that at least one form of alcoholism is strongly genetically predetermined,” said Dr. Ernest P. Noble, a UCLA psychiatrist and biochemist who co-authored the study published today in the Journal of the American Medical Assn.

“It does not mean that if you don’t have this gene the environment can’t make you become an alcoholic,” said Noble. “. . . What we want to caution is certainly (the finding) is not a cure. It’s just a marker for potential predisposition.”

The researchers examined genetic material from the brains of 70 people who had died--35 of them severe alcoholics, 35 of them not alcoholics. They looked for an uncommon form of a gene that has long been believed to play a role in addictive behavior.

They found the gene in 77% of the samples from the alcoholics. It was absent in 72% of the samples from non-alcoholic people. The researchers said the identifying marker, known as the A1 allele of the dopamine D2 receptor gene, is present in 60 million Americans.

“If you do have this gene, it doesn’t necessarily mean that you’re going to be an alcoholic,” Noble, a professor at the UCLA School of Medicine, said in an interview. “Or the contrary: If you don’t have it, it doesn’t mean you’re spared.

“But if you do have the gene, and you’re in an environment that has a lot of alcohol, I think the chances of becoming an alcoholic are quite good,” he said.

It is unclear precisely how the gene might exert its effect. One possibility is that it might interfere with cells’ uptake of dopamine, a neurotransmitter associated with pleasure-seeking behavior, one researcher speculated.

A person with the gene might have difficulty experiencing the pleasurable sensation brought on by dopamine, said Kenneth Blum of the University of Texas Health Science Center, San Antonio, the lead author on the paper. “You would be drawn to alcohol because one of the things alcohol does is release excess amounts of dopamine,” he said.

It is not yet possible to screen people for the presence of the gene. It could take at least five more years of research to understand better the gene’s role in alcoholism and to design a screening test for it and other genes, the researchers said.

Alcoholism--a chronic, progressive and potentially fatal condition--is believed to afflict approximately 18 million Americans. It is blamed for about 97,500 deaths annually from medical consequences, accidents, suicides and alcohol-related murders.

There is evidence that some forms of alcoholism run in families. Some of the evidence comes from studies of adoptive children, which showed that children of alcoholics raised in non-alcoholic homes have the same high risk of alcoholism as those raised in alcoholic homes.

But researchers had been unable to identify a so-called “alcogene”--a specific gene that might explain those findings. In its absence, many have disagreed on the relative roles of heredity and environment, and on whether alcoholism is a behavior or a disease.

Those who emphasize heredity tend to believe that alcoholism is a disease and that moderate drinking may be impossible for alcoholics. They argue that alcoholics deserve compassion, not disapproval, and that treatment must aim for abstinence.

On the other side, those who emphasize the importance of environment in alcoholism tend to look to cultural influences, family behavior and peer pressure. Some are skeptical of the notion that alcohol is a disease; they see it as a behavior that can be modified.

Both sides admit the possibility that both environment and heredity might play a role.

“(This study) is a scientific bit of proof that there is a physiological component,” said Dr. Joe Takamine, a Los Angeles County specialist in chemical dependency. “It’s not going to be labeled as the cause or the only cause. . . . But this is evidence. And it comes at a desperately needed time.”

Others, however, cautioned against oversimplification.

“(The inherited disease concept) gives a message to people that don’t have a family history that they are not at risk for developing alcohol problems,” said Alan Marlatt of the University of Washington. “It gives people the message that they’re safe.

“What I’m afraid this (study) may do is just convince everybody more (that) it’s a genetic disease and that’s all,” said Marlatt. “The scientific evidence up to now doesn’t give us much guarantee that we can really predict who is going to become alcoholic.”

Several researchers, including officials of the National Institute on Alcohol Abuse and Alcoholism, expressed reservations about the study. They said its size was small and questioned whether the alcoholic and non-alcoholic subjects were directly comparable.

Although Noble, Blum and the other researchers reported that the two groups of subjects were matched in terms of age, gender and race, other specialists in the field questioned whether other differences between the two groups influenced the results.

They were unanimous in stating that the finding must be confirmed and explored further in larger studies. The problem of confirmation has bedeviled other researchers claiming recently to have found genetic roots for other neuropsychiatric disorders.

For example, scientists have been unable to replicate a 1987 finding of genetic links to manic-depressive disorder. And different research groups have reached different conclusions in searching for a genetic basis for schizophrenia.

“The history of gene research in behavioral disorders has been an inability to reproduce other people’s findings,” said Dr. Donald Goodwin, a professor of psychiatry at the University of Kansas and an early proponent of the idea that alcoholism can be inherited.

“Does that mean they’re wrong?” Goodwin asked. “It could mean there are multiple genetic factors in heterogeneous illnesses. Or it could mean the methodology was wrong. Or it could mean some other factor entered into it.”