A genome-wide study into the genetic roots of alcohol dependence has identified several areas of DNA that seem to contribute to alcoholism. The study is one of the first to be published as part of the Genes, Environment and Health Initiative (GEI), a $48 million project funded by the National Institutes of Health.
"We didn’t identify an alcoholism gene, but I believe these findings eventually will help us learn more about the genetic architecture underlying a complex illness like alcoholism," said Laura Jean Bierut, M.D., professor of psychiatry at Washington University School of Medicine in St. Louis. Bierut heads the national GEI addiction study.
The study investigators looked at DNA from 1,897 alcoholics and 1,937 people who drank but were not considered dependent on alcohol. These people were part of the Study of Addiction: Genetics and Environment (SAGE). Analyzing the SAGE data yielded 15 areas of DNA – known as single nucleotide polymorphisms – that seemed to be linked to alcoholism.
When the researchers went back and examined DNA from 4,000 people in another set of data, the research team could not identify any significant association between the single nucleotide polymorphisms found in the SAGE study and a risk for alcohol dependence.
"Admittedly, we had a rather conservative statistical model, and some of these DNA regions may have a modest influence on alcohol dependence," said Bierut. ‘But none of the top 15 genetic influences from the SAGE study were replicated in the data from other studies. The fact that the findings didn’t replicate between the datasets doesn’t mean that these DNA regions are not involved. We may just have only one small piece of the story."
