Researchers at the Molecular Neurobiology Branch of the National Institute on Drug Abuse report that their comprehensive scan of the human genome is the first time the new technology has been used to comprehensively indentify genes linked to substance abuse.
Genetic VariationsMany previous studies have linked specific genes to alcoholism, but the NIDA researchers identified clusters of genetic variations in 51 chromosomal regions that they believe play a role in alcohol addiction through cell-to-cell communication, control of protein synthesis, regulation of development, and cell-to-cell interactions.
The human genome consists of approximately three million base pairs of DNA in each set of chromosomes. When researchers find differences in the sequences of DNA pairs they are genetic variations, which can play a role in a higher hor lower risk of contracting diseases.
Genetic Tendency No GuaranteeBecause someone has a genetic tendency to develop a disease, it does not guarantee they will have the disease, only that they are at higher risk for doing so than the average person.
National Institutes of Health officials say, however, if the genes responsible for a high risk of substance abuse can be pinpointed, it could revolutionize treatment and prevention of alcoholism.
"Tools such as pooled data genome scanning give us a completely new way of looking at complex biological processes, such as addiction," says Dr. Elias A. Zerhouni, director of the National Institutes of Health, in a new release announcing the findings. "The ability to pinpoint genes in the human genome responsible for disease has the potential to revolutionize our ability to treat and even prevent diseases."
Alcoholism Runs in Families"Previous studies established that alcoholism runs in families, but this research has given us the most extensive catalogue yet of the genetic variations that may contribute to the hereditary nature of this disease," says NIDA Director Dr. Nora D. Volkow. "We now have new tools that will allow us to better understand the physiological foundation of addiction."
"This is an important contribution to studies of the genetics of alcoholism and co-occurring substance use disorders," adds Dr. Ting-Kai Li, director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA). "The findings will open many new avenues of research into common factors in genetic vulnerability and common mechanisms of disease."
Led by Dr. George Uhl, the scientist developed a new genetic platform that allowed them to generate 29 million genotypes and analyze 104,268 genetic variations in DNA samples from people who were and were not alcohol dependent.
Vulnerable to Addition"The observations from this study provide a graphic display of the close relationships between genetic vulnerability to alcoholism and genetic vulnerability to other addictions," says Dr Uhl. "Ongoing and future studies will help us to identify how the variations in these candidate genes contribute to differences in addiction vulnerability." "We know that vulnerabilities to substance abuse involve complex traits with strong genetic influences," adds Dr. Volkow. "Finding ways to identify who is most physiologically vulnerable to addiction will be a tremendous step towards more effective prevention and treatment approaches."
National Institute on Drug Abuse
The study will be published in the December 2006 issue of the American Journal of Medical Genetics Part B (Neuropsychiatric Genetics) and can be viewed online.