39 genes behind alcoholism identified

Hooked on alcohol? Your genes may be to blame!
Scientists have identified a group of 39 genes that together are strongly associated with alcoholism.
There is good evidence from studies of families and twins that genetics plays an important role in the development of alcoholism, researchers said.
However, hundreds of genes likely are involved in this complex disorder, with each variant contributing only a very small effect.
Using a new approach that combines genome-wide association studies (GWAS) with information about which human proteins interact with one another, researchers from the University of Iowa Carver College of Medicine and Yale University Medical School have identified a group of 39 genes that together are strongly associated with alcoholism.

"The discovery of these genes may open a new window into the biological mechanisms underlying this alcoholism disorder," said Shizhong Han, UI assistant professor of psychiatry and corresponding author of the study.

"Eventually, it's our hope that the findings might help to develop drugs to treat or prevent this disorder," said Han.
Han and his colleagues based their approach for identifying risk genes on the idea that genes may be "guilty by association" of contributing to the disease.
Although many different genes contribute to alcoholism, these genes, or more precisely, their protein products, are not independent of each other, researchers said.

"The proteins made by these genes could be neighbours, or they could be part of the same functional biological pathway," Han said.
"We took advantage of their biological relatedness to identify a network of genes that interact and together contribute to the susceptibility to alcoholism," said Han.
The team conducted the study by using two large data sets collected for the genetic study of addiction - the Collaborative Study on the Genetics of Alcoholism (COGA) and the Study of Addiction: Genetics and Environment (SAGE).
These data sets document genome-wide common variants information from several thousand people linked to information about these individuals' alcohol dependence or other types of addiction.

No single variant was strongly associated with the condition, but when the researchers integrated information about protein-protein interactions from the Human Protein Interaction Network, they identified a network of 39 genes that was not only enriched for alcoholism-associated genes, but also was collectively strongly associated with alcoholism.
The study was published in the American Journal of Human Genetics.