Blame your genes for your alcoholism

Washington – New studies of families and twins have found evidence that genetics plays an important role in the development of alcoholism.

However, hundreds of genes likely are involved in this complex disorder, with each variant contributing only a very small effect. Thus, identifying individual risk genes is difficult.

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 and Yale University Medical School have identified a group of 39 genes that together are strongly associated with alcoholism.

Shizhong Han, PhD, UI assistant professor of psychiatry and corresponding author of the study, 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- that although many different genes contribute to alcoholism, these genes, or more precisely, their protein products, are not independent of each other.

“The proteins made by these genes could be neighbors, or they could be part of the same functional biological pathway,” Han explained. “We took advantage of their biological relatedness to identify a network of genes that interact and together contribute to the susceptibility to alcoholism.”

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.

The study is published in the American Journal of Human Genetics.