Researchers at the National Institute of Alcohol Abuse and Alcoholism have been unable to confirm a widely publicized study linking a gene to a predisposition to alcoholism.
The finding does not necessarily challenge the idea there may be a genetic predisposition for alcoholism. But the researchers said it suggests that more work will be needed to identify any gene or genes that may be at fault.
In April researchers reported that defects in a gene involved in the transmission of messages between brain cells strongly predisposed people to alcoholism.
But in a study being published today in the Journal of the American Medical Association, the federal investigators report they could not find such an association with the gene.
Dr. David Goldman, the principal investigator and chief of genetic studies at the institute, and his colleagues said they examined the gene in 10 alcoholics, 127 people who were not alcoholics, and two large families that had alcoholic members.
But one of the scientists who made the original observation, Dr. Kenneth Blum of the University of Texas Health Sciences Center in San Antonio, said the discrepancy might be due to differences in the people studied.
Dr. Blum and his fellow researcher, Dr. Ernest P. Noble of the University of California at Los Angeles, studied people who were such intransigent alcoholics that they died of the disease.
Dr. Goldman studied a group that included less extreme alcoholics.
"They are such different populations that you can't compare the studies," Dr. Blum said.
Dr. Goldman agreed that he had studied less severely affected alcoholics. "There could be a subgroup of alcoholics who still have that marker," he said.
The original study gained vast attention.
The investigators had compared the brains of 35 people who died of alcoholism with those of 35 people who were not alcoholics. They found that the alcoholics had a variant of a gene that could determine the way the brain responds to pleasure-seeking behavior.
But Dr. Goldman said other researchers were highly dubious that alcoholism could be explained so simply.
"Although it is not my opinion, many felt that it is too much to hope for," Dr. Goldman said. "Among the scientific community, there was a great deal of skepticism of that sort."