There are some traits that clearly run in families. In my husband’s family, it is the shockingly blue eyes, and in mine, it’s the curly hair. There are also a whole set of traits and illnesses that feel like they must run in families, even if a clear connection hasn’t yet been determined by science. Alcoholism is one of those illnesses.
Whether there is a genetic link underlying alcoholism has been a question scientists have been studying for years. As technology improves, genetic research is becoming increasingly sophisticated.
Scientists have determined that, yes, there is a genetic component to alcoholism, although it is complicated and only partially understood.
To give you some background, David Ball wrote an editorial piece back in 2004 that outlined some of history of the research in regards to a potential inherited tendency towards alcoholism. Genetic approaches to alcohol dependence is a good primer, and introduces some of the common terminology used when you are exploring genetic research. A less scholarly, although complete ,description of the subject can be found here.
When you start to read about hereditary alcoholism, it becomes clear that it is a complicated biological phenomenon. As a disease, it is generally described as being heterogeneous. This means that it is a disease that does not manifest the same way in every person. Although there does seem to be a genetic component, there does not seem to be one single ‘alcoholism gene.’ Studies to date have shown a few different possible methods via which the disease might get its start at a genetic level.
One study, published in 1990 by Blum, et.al, which you can read about in full here, indicated the first positive genetic association of a specific dopamine receptor site with alcoholism. In this study, researchers tested the brain tissue of both alcoholics and non-alcoholics for a particular variant of a dopamine receptor gene. In the case of this research study, the 77% of the alcoholics in the study had the receptor gene present, and 72% of the non-alcoholics didn’t have the receptor gene present. Per the commentary by Mr. Ball in the summary article I link to earlier, there have been mixed results when replicating this study. (A good explanation of dopamine and the role it plays in our bodies can be found here).
This study also raises the idea that there is more than one gene that indicates the likelihood of alcoholism and suggests that there are 2 genetic forms of alcoholism - Type 1 and Type 2 - and they are distinguished by differing characteristics of alcohol-related problems and personality-traits.
Furthermore, there are studies that indicate a gene might be responsible for excessive drinking, and for specific responses to alcohol. Here are a wide variety of studies that related to hereditary alcoholism.
Studies on alcoholism have been done on twins and adopted children. This helps establish a difference between the nature vs. nurture side of alcoholism. It seems that consistently, children who are born to, but not raised by an alcoholic parent, have a greater likelihood of also being an alcoholic.
More recently, some of the science seems to indicate that the same genes that cause someone to be more susceptible to alcoholism likely cause that person to be susceptible to other addictions. You can read about it here and here.
A very public project of genetic research was the Human Genome Project. As one of the most widely publicized scientific studies of all time, the goal was to identify all the genes in human DNA. Taking 13 years to complete, and originally touted as the research that would allow us to understand everything about our own genetic makeup, in reality just got us to the starting line. From the HGP, we know that human DNA is comprised of approximately 30,000 genes, and 99.9% of those genes are identical same in all people. With the information gathered about our genome, science has the context for much greater genetic understanding of what is happening with people.
The next area of genetic research that might give us some insight into alcoholism is that of epigenetics. There is a great video explanation of the field of epigenetics from a past episode of NOVA Science Now. This piece talks about how identical twins, who have exactly the same DNA, often end up differing more and more as their lives progress. Epigenetics is the study of what causes a particular gene to be ‘on’ or ‘off’.
In the case of a genetic predisposition to alcoholism, it might very well be the epigenome that controls whether that gene is expressed or not. The analogy they use on NOVA Science Now episode is that our genome is like the hardware of a computer, and the epigenome is the software that runs everything.
Much of what I have read indicates that just because you are genetically predisposed to a disease does not mean that you are absolutely going to get that disease. It indicates that you should be alert to potential warning signs. In the case of diseases such as cancer, regular and thorough screening is important. For alcoholism, it’s keeping an eye on actions, motivations, and responses to alcohol.
For children of alcoholics, this is of course a very troublesome issue. If you have a parent who is an alcoholic, then you potentially have an increased risk for alcoholism. For adult children of alcoholics, I found a screening questionnaire that seems to be geared towards understanding how profoundly a parent’s alcoholism may have affected you. For people who suspect their own alcoholism, here are a series of tests you can opt to look at in regards to your own actions and behaviors.
Next up on this topic, personal genomics.
Whether there is a genetic link underlying alcoholism has been a question scientists have been studying for years. As technology improves, genetic research is becoming increasingly sophisticated.
Scientists have determined that, yes, there is a genetic component to alcoholism, although it is complicated and only partially understood.
To give you some background, David Ball wrote an editorial piece back in 2004 that outlined some of history of the research in regards to a potential inherited tendency towards alcoholism. Genetic approaches to alcohol dependence is a good primer, and introduces some of the common terminology used when you are exploring genetic research. A less scholarly, although complete ,description of the subject can be found here.
When you start to read about hereditary alcoholism, it becomes clear that it is a complicated biological phenomenon. As a disease, it is generally described as being heterogeneous. This means that it is a disease that does not manifest the same way in every person. Although there does seem to be a genetic component, there does not seem to be one single ‘alcoholism gene.’ Studies to date have shown a few different possible methods via which the disease might get its start at a genetic level.
One study, published in 1990 by Blum, et.al, which you can read about in full here, indicated the first positive genetic association of a specific dopamine receptor site with alcoholism. In this study, researchers tested the brain tissue of both alcoholics and non-alcoholics for a particular variant of a dopamine receptor gene. In the case of this research study, the 77% of the alcoholics in the study had the receptor gene present, and 72% of the non-alcoholics didn’t have the receptor gene present. Per the commentary by Mr. Ball in the summary article I link to earlier, there have been mixed results when replicating this study. (A good explanation of dopamine and the role it plays in our bodies can be found here).
This study also raises the idea that there is more than one gene that indicates the likelihood of alcoholism and suggests that there are 2 genetic forms of alcoholism - Type 1 and Type 2 - and they are distinguished by differing characteristics of alcohol-related problems and personality-traits.
Furthermore, there are studies that indicate a gene might be responsible for excessive drinking, and for specific responses to alcohol. Here are a wide variety of studies that related to hereditary alcoholism.
Studies on alcoholism have been done on twins and adopted children. This helps establish a difference between the nature vs. nurture side of alcoholism. It seems that consistently, children who are born to, but not raised by an alcoholic parent, have a greater likelihood of also being an alcoholic.
More recently, some of the science seems to indicate that the same genes that cause someone to be more susceptible to alcoholism likely cause that person to be susceptible to other addictions. You can read about it here and here.
A very public project of genetic research was the Human Genome Project. As one of the most widely publicized scientific studies of all time, the goal was to identify all the genes in human DNA. Taking 13 years to complete, and originally touted as the research that would allow us to understand everything about our own genetic makeup, in reality just got us to the starting line. From the HGP, we know that human DNA is comprised of approximately 30,000 genes, and 99.9% of those genes are identical same in all people. With the information gathered about our genome, science has the context for much greater genetic understanding of what is happening with people.
The next area of genetic research that might give us some insight into alcoholism is that of epigenetics. There is a great video explanation of the field of epigenetics from a past episode of NOVA Science Now. This piece talks about how identical twins, who have exactly the same DNA, often end up differing more and more as their lives progress. Epigenetics is the study of what causes a particular gene to be ‘on’ or ‘off’.
In the case of a genetic predisposition to alcoholism, it might very well be the epigenome that controls whether that gene is expressed or not. The analogy they use on NOVA Science Now episode is that our genome is like the hardware of a computer, and the epigenome is the software that runs everything.
Much of what I have read indicates that just because you are genetically predisposed to a disease does not mean that you are absolutely going to get that disease. It indicates that you should be alert to potential warning signs. In the case of diseases such as cancer, regular and thorough screening is important. For alcoholism, it’s keeping an eye on actions, motivations, and responses to alcohol.
For children of alcoholics, this is of course a very troublesome issue. If you have a parent who is an alcoholic, then you potentially have an increased risk for alcoholism. For adult children of alcoholics, I found a screening questionnaire that seems to be geared towards understanding how profoundly a parent’s alcoholism may have affected you. For people who suspect their own alcoholism, here are a series of tests you can opt to look at in regards to your own actions and behaviors.
Next up on this topic, personal genomics.
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Kerry Lauerman
Joan Walsh
Salon.com
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