A national team of investigators led by psychiatric geneticists at Washington University School of Medicine in St. Louis has identified a gene that appears to be linked to both alcoholism and depression.
The study, published in the September issue of the journal Human Molecular Genetics, is the first to identify a specific gene associated with both depression and alcoholism.
“Clinicians have observed a connection between these two disorders for years, so we are excited to have found what could be a molecular underpinning for that association,” says principal investigator Alison M. Goate, D. Phil., the Samuel and Mae S. Ludwig Professor of Genetics in Psychiatry, professor of genetics and professor of neurology at the School of Medicine.
The research is part of the national Collaborative Study on the Genetics of Alcoholism (COGA), an ongoing project involving the collection of interviews and DNA samples from more than 10,000 people with alcohol dependence and their families. Participants in the COGA study usually have several family members with alcohol dependence. Because depression and alcoholism often occur together, many COGA participants also suffer from depression.
The Washington University team analyzed DNA from 2,310 people from 262 families in which at least three members were alcoholic. Using DNA-analysis techniques, the researchers found that one region on chromosome 7 looked remarkably similar in most alcoholics.
They then examined DNA from depressed COGA participants, independent of alcohol usage and found that the same distinguishing region on chromosome 7 also looked similar in most depressed individuals. In addition, participants with both depression and alcoholism were the most likely to have these similarities on chromosome 7.