Genes May Determine Alcohol Dependence
Parents don't just pass down their eye and hair color. New research has found a significant link between alcohol dependency and abnormalities on chromosome 5q13.2. And these gene mutations can be inherited by offspring.
The heritability of alcohol dependence comes down to genetic mutations called copy number variations (CNV). These are structural changes in genetic code where large regions of the genome have either been deleted, leaving fewer than a normal number of genes, or have been duplicated, leaving more than the normal number.
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"They can be inherited or be a genetic mutation that neither parent possessed nor transmitted," said study author John P. Rice of Washington University.
Rice and his team interviewed close to 4,000 participants to assess their alcohol intake and used the the Illumina Human 1M array to assess the CNV on each person's genome. The heritability range of these genetic traits falls between 50 and 60 percent for both men and women, according to Medical Daily.
"The region identified on chromosome 5 contains several genes that have been implicated is rare neurological disorders and play a role in the nervous system. It will be a challenge to understand what gene(s) are causing this association and how they work to increase one's risk for [alcohol dependence]," Rice said.
Excessive drinking - including binge drinking and consistent heavy drinking - is the third leading lifestyle-related cause of death for the United States, according to the Centers for Disease Control.
"Alcoholism's pervasive impact on public health and its heritability make searches for genes influencing vulnerability a priority," said David Goldman, chief of the lab of neurogenetics at the National Institute on Alcohol Abuse and Alcoholism. "Although only a few genes influencing alcoholism risk have been discovered so far, we can expect this picture to change rapidly as more powerful genomic tools, including genotyping arrays and next-generation sequencing, are applied, and as geneticists become ever more ambitious in the size and phenotypic depth of the populations they study."
"This is a carefully done study and results are conservatively interpreted," Goldman said, and Rice agreed, saying that the results need to be replicated in independent samples.
"If they hold, then researchers who study the basic biology of how changes in the genome lead to increased or decreased risk for illness can add to our understanding. It is important to note that the associations are modest, so these findings cannot be used to predict who will become an alcoholic. The results open up a new line of investigation, but it can take many years before we have a true understanding," Rice said.
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