Previous studies of twin siblings and families point to a strong genetic role in the development of an alcohol abuse problem. The trouble is finding out which among the 24,000 human genes are most responsible for the vulnerability. Researchers from Yale University Medical School and the University of Iowa used a technique called genome-wide association studies in order to identify which proteins work together. The technique, along with what the researchers already knew about gene protein interactions, led them to identify 39 genes which they feel are most responsible for alcoholism. The study team used data that had been collected through two large prior studies: the “Study of Addiction: Genetics and Environment” and the “Collaborative Study on the Genetics of Alcoholism.” These studies provided information on genome-wide variants among thousands of people with alcohol addiction or other substance abuse problems. Looking at groups of genes that are already related gave the research team a starting point when sifting through thousands of potentially associated genes. The genes’ protein by-products worked interdependently provided the most likely candidates since alcohol abuse is a complex combination of multiple factors which are reasonably assumed to be linked together somehow. The proteins these researchers looked at were either in proximity to one another or were shared members of a known biological pathway. By combining the genetic information from the two large-scale studies, the team was able to identify which genes were most commonly active in addicted subjects. The researchers hunted for the protein to protein relationships in order to finally identify the 39 genes. Those 39 genes not only proved to be statistically relevant among the thousands of study subjects, but they are also recognized as connected to things like alcohol tolerance and brain communication in the form of synapse transmission. The team utilized three extra datasets in order to verify their findings: two studies of subjects of European descent, and one study of subjects of African descent. As a further check the related genes were analyzed for any possible connection to other diseases such as diabetes, depression or bipolar disorder. The gene network did not appear responsible for these conditions, leaving researchers to conclude that the 39 genes were, in fact, uniquely responsible for the development of alcoholism. Having these particular genome-associations does not mean that a person will definitely suffer an alcohol use disorder, only that biological conditions are favorable for that to happen. Environmental factors such as home life and friendships also play a role. Nonetheless, it is hoped that by narrowing down the specific genes which are most closely associated with alcoholism scientists can soon gain even more detailed knowledge about biological triggers. The end result could be targeted drugs which more effectively treat alcoholism, or perhaps even the ability to prevent the disease from taking hold in the first place.
