Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, April 18, 1990 TAG: 9004180347
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
SOURCE: The New York Times
DATELINE: NEW YORK LENGTH: Long
The finding should open new avenues of research for prevention and treatment of alcoholism, which affects one in every four families in the United States, the researchers said.
The finding holds promise that a blood test could someday be devised to identify people who are most at risk, the scientists said in a report in The Journal of the American Medical Association.
New drugs for alcoholism could eventually emerge from further research aimed at determining how the gene contributes to abuse, addiction and the resulting damage to the liver, brain and other organs, the research team said.
The team was headed by Dr. Ernest P. Noble of the University of California at Los Angeles and Dr. Kenneth Blum of the University of Texas Health Science Center in San Antonio.
The researchers said the gene linked to alcoholism was the receptor gene for dopamine, a chemical that plays a crucial role in helping brain cells communicate with each other. Earlier research showed that dopamine plays a role in pleasure-seeking behavior, including alcoholism.
The scientists studied the brains of 35 people who died from alcoholism and 35 others who were not alcoholics. The gene was present in 77 percent of the alcoholics and absent in 72 percent of the non-alcoholics in the study. The researchers said they identified the gene through sophisticated laboratory tests and statistical analyses.
While scientists consider it important to identify a gene, they say it is only a first step in determining what effect the gene has on a person's biochemistry and physiology. It will take many additional laboratory studies to document those effects, and then studies on humans will be needed to correlate the findings with the presence or absence of alcoholism in individuals and families.
Theoretically, the gene could increase or decrease the number of receptor sites in brain cells where dopamine can act or affect how well it binds to the sites. If the gene altered the number of sites, it could affect the amount of pleasure created by a given amount of alcohol and lead to a craving for alcohol to release more dopamine.
Scientists generally accept the notion that alcoholism is based on complex genetic, cultural and social factors. Increasing evidence over the last 30 years that heredity played a role has set off an intense search for proof.
The researchers said no single gene, including this one, causes all forms of alcoholism. Some people with the gene they studied did not become alcoholics, while some who lacked the gene did become alcoholics, they said. Social and cultural factors may set off the affliction for many alcoholics who are not genetically predisposed to the disease.
In an editorial in the same issue of the journal, Dr. Enoch Gordis, the director of the National Institute of Alcohol Abuse and Alcoholism, and three other scientists from the institute in Rockville, Md., said the statistical evidence for the newly reported gene link to alcoholism was surprisingly strong.
But the federal scientists said the findings had to be repeated on much larger numbers of alcoholics, in part because the new study was necessarily small.
Gordis said in an interview that the newly reported gene "may not be specific for alcoholism but it might have a more general influence on appetite, personality and behavior."
Noble agreed, saying that "the good Lord did not make an alcoholic gene, but one that seems to be involved in pleasure-seeking behaviors."
More than 18 million Americans suffer from alcohol abuse and about 100,000 people die from it each year. Fetal alcohol syndrome, which causes mental retardation and facial deformities, affects about one in every 500 babies born in the United States.
Scientists have long known that alcoholism runs in families. But it has been difficult to separate the hereditary and environmental components that have made alcohol the most widely used and destructive drug in the United States.
The increasing evidence for a genetic role in alcoholism has come from a number of studies of animals and humans. For example, scientists have developed strains of rats with different genetic predispositions to drink or not to drink alcohol freely.
In humans, studies of twins and adopted children have shown that alcoholism can be inherited. Some studies have shown that genetics were better predictors of alcoholism than environmental factors.
Children of alcoholics have a four times greater risk of developing alcoholism than children of non-alcoholics. Also, different types of brain wave patterns have been identified in young sons of alcoholic fathers.
In their hunt for a gene for alcoholism, Noble and Blum studied the brains of dead alcoholics and non-alcoholics that were stored at a national brain bank at the Wadsworth Veterans Affairs Medical Center in Los Angeles. The brains were from men and women, blacks and whites.
Two psychiatrists independently verified that the 70 brains were from alcoholics or non-alcoholics by examining medical records and interviewing family members and friends. The psychiatrists determined the amount of each person's alcohol consumption and the cause of death, including cirrhosis, cancer and traffic accidents.
Noble is a biochemist and psychiatrist and former head of the National Institute of Alcohol Abuse and Alcoholism. Blum is a pharmacologist.
A goal that will take longer to achieve, the scientists said, is to develop genetic engineering techniques to eliminate the gene from affected people.
by CNB