People with blue eyes may be at greater risk for becoming alcoholics, according to a novel study by genetic researchers at the University of Vermont.
The study is the first to identify a direct link between a person’s eye color and alcohol dependency. The researchers hope to get closer to finding the roots of not only alcoholism but other psychiatric illnesses as well.
“This suggests an intriguing possibility: that eye color can be useful in the clinic for alcohol dependence diagnosis,” says Arvis Sulovari, a doctoral student in cellular, molecular and biological sciences.
Researchers Sulovari and Dawei Li, Ph.D., assistant professor of microbiology and molecular genetics, discovered that primarily European-Americans with light-colored eyes — including those with green, grey, and brown in the center — had a higher incidence of alcohol dependency than people with dark brown eyes. The strongest tendency for alcoholism was found among blue-eyed individuals.
The study outlines the genetic components that determine eye color and shows that they line up along the same chromosome as the genes related to excessive alcohol use.
But, Li says, “we still don’t know the reason” and more research is needed.
Li has studied psychiatric genetics for a decade. During that time, he has collaborated with other researchers to build a clinical and genetic database of more than 10,000 individuals.
Most of them have been African-Americans and European-Americans, diagnosed with at least one psychiatric illness. Many have multiple diagnoses of diseases, including depression, schizophrenia and bipolar disorder, as well as addiction and alcohol or drug dependence.
“These are complex disorders,” he said. “There are many genes, and there are many environmental triggers.”
From that extensive database, the researchers filtered out the alcohol-dependent patients with European ancestry, a total of 1,263 samples. After Sulovari noticed the eye-color connection, they retested their analysis three times, arranging and rearranging the groups to compare age, gender and different ethnic or geographic backgrounds, such as southern and northern parts of the continent.
Li wants to delve deeper into the relationship between cultural background and genetic makeup, continuing his quest to find the underpinnings of mental illness. His greatest challenge, he says, is that all the genes identified in the past 20 years “can only explain a small percentage of the genetics part that has been suggested. A large number is still missing, is still unknown.”
“What has fascinated me the most about this work has been investigating the interface between statistics, informatics, and biology,” said Sulovari. “It’s an incredible opportunity to study genomics in the context of complex human diseases.”
Their findings are published in the American Journal of Medical Genetics: Neuropsychiatric Genetics.
Source: University of Vermont