As a genetic counselor, with every patient we ask about a person’s family medical history. It’s common for genetic counselors to hear about family members who have various health concerns, mental health disorders, or how a family member died. It’s also fairly common to hear about a family member who struggles with addiction. Addiction is a chronic disease that affects different parts of the brain. When a person has an addiction, it’s not so easy to just stop. In the case of alcoholism, which is defined as a maladaptive pattern of drinking too much alcohol leading to serious physical, mental, and social problems, if a person tries to stop drinking their body might not be able to handle it without medical intervention. Often a genetic counselor will be asked, is alcoholism genetic?
Alcoholism, like depression and other health conditions, is thought to be caused by a combination of genetics and environment. Researchers and health care providers have seen alcoholism running in families for a long time, but we are still continuing to discover the exact causes. To date, we have discovered multiple genes that are thought to play a prominent role in alcoholism. Adoption studies indicate that people who are adopted and struggle with alcoholism correlate more strongly with their biological family than their adoptive family. Twin studies have indicated that alcoholism could have a hereditary component of approximately 45-65%. While we don’t have a single gene that causes alcoholism, we can determine based on family history and genetic studies of alcoholism that a person can have a genetic predisposition for alcoholism.
There are two genes that have been shown to have the clearest link to alcoholism. Alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2) both play an important role in the metabolism of alcohol in the liver. For some people with a specific mutation, or change in their ALDH2 gene, the way their body processes alcohol is different than people without that mutation. These people tend to display the “Asian flushing reaction” with even small amounts of alcohol consumed, which can include facial flushing, tachycardia, and nausea. Often this type of reaction will make people not consume large amounts of alcohol, simply because they don’t like the reaction afterwards. Individuals with certain mutations in the ADH1B gene can metabolize alcohol at 30-40-fold higher rates than those without the gene mutation, which then triggers a negative reaction to the alcohol consumption. This particular mutation in ADH1B gene has not been studied as well in Europeans compared to Chinese and Japanese.
It has also been thought that the genetic variations of those who suffer from alcoholism can manifest in different ways. Some studies have shown that people with a personal or family history of alcoholism are found to have a smaller amygdala, which is a part of the brain that controls cravings. In addition, people with a genetic predisposition to alcoholism may exhibit fewer warning signs from their bodies when they need to stop drinking alcohol. People who are genetically predisposed to alcohol also have been found to have unusual serotonin levels, which is an important mood-regulating neurotransmitter.
Again, the answer is yes, you can have a genetic predisposition to alcohol. While we cannot do genetic testing to see if someone has “the gene” for alcoholism, based on personal and family medical history we can determine if you have a genetic predisposition to alcohol. If you are concerned about your family history, please contact AT-GC to meet with a genetic counselor or read more about a person’s genetic predisposition for other medical conditions, including cancer and depression.