An association between alcohol dependence (AD) and a cluster of genes on chromosome 11, has been found in a genome-wide association study.
"Previous studies have looked at one or a few genes at a time, choosing the genes based upon hypotheses about possible mechanisms underlying differences in risk for alcoholism," said Howard J. Edenberg, Distinguished Professor at the Indiana University School of Medicine and corresponding author for the study.
"We chose to examine the entire genome, all the genes at once, as an unbiased approach that has the potential of uncovering previously unsuspected genes," Edenberg added.
Researchers used data drawn from the ongoing, seven-center Collaborative Study on the Genetics of Alcoholism (COGA).
The primary analyzes were in 1399 unrelated European Americans (847 cases, 552 controls); a smaller group of African Americans was also studied (345 cases, 140 controls).
Researchers then genotyped most of the top 199 single nucleotide polymorphisms (SNPs) - DNA sequence variations that occur when a single nucleotide in the genome sequence is altered - and examined whether the genes harboring these SNPs were expressed in human brain or were differentially expressed in the presence of alcohol in lymphoblastoid cells.
"Although we did not find definitive evidence for the role of any one gene, we found suggestive evidence that a gene or genes in one region of chromosome 11 might be involved," Edenberg said.
"We also provided support for several genes that had been found by others. Identifying additional genes that might be related to the risk for alcoholism is an important starting point.
"Future studies will need to confirm their importance in other populations, to determine which aspect of the disease process they might impact, and to examine the mechanisms through which they work," Edenberg added.
The results of the study will be published in the May 2010 issue of Alcoholism: Clinical and Experimental Research.