A new study has identified a genetic variant that indicates an increased risk of alcohol…
Variations of Single Gene May Increase Odds for Alcoholism
Alcoholism (i.e., physical alcohol dependence) is known to have a strong genetic component, and researchers continue to uncover specific genes and gene combinations that contribute to risks for the condition. In a study published in July 2014 in the journal Alcoholism: Clinical & Experimental Research, a group of South Korean researchers used a combination of genetic testing and a screening tool called the Alcohol Use Disorders Identification Test (AUDIT) to determine if multiple forms of a single gene, called HTR7, can increase the odds that any given person will become physically dependent on alcohol.
The HTR7 Gene
The HTR7 gene plays an important role in human health by helping to regulate the production of a chemical in your body called serotonin, which has recognized functions that include regulating the natural cycle of sleeping and waking, regulating your hunger levels and regulating your day-to-day mood. Like many genes, HTR7 comes in a multitude of forms or variations; any one of these variations can affect the gene’s function in small or large ways. As a rule, the form of HTR7 (or any other gene) present in your body is determined by the pool of possible variations passed down through your family bloodline. Health problems previously associated with changes in this gene include autistic spectrum disorder (i.e., autism) and certain other mental health conditions. The potential involvement of HTR7 in the risks for alcoholism has only been understood for the last several years.
Alcoholism and AUDIT
In its essence, alcoholism is defined by a long-term alteration of basic brain chemistry that triggers a need for continuing alcohol intake. People affected by this need commonly experience a range of characteristic physical and behavioral symptoms. Up until 2013, the medical and research communities viewed these symptoms as unique and separate from the symptoms of serious, non-addicted alcohol abuse. However, the preponderance of evidence gathered by doctors and researchers now indicates that alcoholism symptoms and alcohol abuse symptoms can sometimes appear in highly similar forms or appear at the same time in a single person. For this reason, alcoholism and alcohol abuse are now considered components of a more inclusive condition known as alcohol use disorder.
The Alcohol Use Disorders Identification Test is a screening tool created in the 1980s and 1990s by specialists at the World Health Organization. It is not intended to help doctors make an official diagnosis of alcoholism or alcohol use disorder. Instead, it helps doctors identify people likely affected by alcoholism or alcohol use disorder, as well as people at risk for developing problems. The standard version of AUDIT contains 10 questions that explore the issue of problematic drinking; a shorter version, called AUDIT-C, contains only three questions.
Role in Alcoholism Risks
In the study published in Alcoholism: Clinical & Experimental Research, researchers from several South Korean universities and hospitals used genetic testing to look for variations of the HTR7 gene in 903 adults. Four hundred fifty-nine of these adults had previously received a diagnosis for alcoholism/alcohol use disorder; the remaining 444 participants did not have an alcoholism history. The genetic testing focused on the identification of different forms of HTR7 in both groups of study participants. The researchers used a combination of the results of this testing and the results of AUDIT screening to determine if specific forms of the gene can increase a person’s alcoholism risks.
All told, the researchers identified 22 variations of the HTR7 gene. Based on the known incidence of alcoholism in the study participants, they linked seven of these variations to an increased risk for becoming physically dependent on drinking. After reviewing the results of the AUDIT screenings, they identified another eight variations of the gene that may increase the risks for alcoholism. In addition, they identified three combinations of HTR7 and other genes that may increase a person’s odds of developing alcoholism.
The study’s authors consider their work to be largely preliminary. Before anyone can say for sure that the identified variations in HTR7 do or do not increase alcoholism risks, they believe their results must be repeated by other researchers. They also believe other researchers must uncover real-world differences in alcoholism rates that support the importance of the genetic variations they found. Still, the authors feel they may have isolated one of the meaningful inherited risks for diagnosable drinking problems.