Genetic factors influencing alcohol dependence
As a follow up to last weeks post about alcoholism link to genetics I did a little more digging and pulling up a more recent meta-analysis of studies regarding genetic links to alcoholism. There is a "fourfold enhanced alcohol dependence risk in relatives of alcoholics" other studies including twin studies and adopted sibling studies support the conclusion that the role genetics and habitability play in alcoholism is between 40% and 60%. This is quite a significant amount, and the genes specifically evolved in this condition both seem to be specific to the drug alcohol but also more generic factors that are involved in behavior and other mental disorders.
The relevant genes that influence a range of intermediate characteristics that are specific to alcohol dependence risk include low sensitivity response to alcohol. This characteristic predicts later heavy drinking and alcohol dependence but not other drugs. Other genetic variations that are specific to alcohol dependence include genes related to alcohol metabolizing enzymes. Alcohol dehydrogenase gene on chromosome 4 specifically seems to have a potential impact also on the dopamine reward system. Other polymorphisms that are possibly associated are the dopamine receptor D4 gene on chromosome 11 and dopamine receptor D2 gene on chromosome 2.
There are genetic factors that appear to have an influence on alcoholism but are not specific to the drug alcohol. There seems to be a correlation between personality characteristics such as impulsivity, sensation seeking, and impaired ablility to learn from mistakes. The GABA A receptor is a major inhibitory neurotransmitter and is reported to be associated with the phenotypes that are related to alcoholism and other addictions as well as mental disorders such as schizophrenia and depression. Schizophrenia and depression are thought to be genetically influenced as mentioned above and these syndromes also enhance the risk for alcohol dependence.
It is still important to note that while there is definitely more progress made in this study and the study of other conditions with a tie to mental conditions there is still a lot that can be analyzed. Also just because there is more evidence that there are genetic aspects that influence addiction, and mental disorders it does not mean that they will develop in the offspring. The environment, culture and attitudes that a person are raised still play a significant role, approximately 40% on the variance of risk in developing a heavy drinking problem. It is important here also to keep in mind that for things like this there may never be able to be a blanket protocol, rule or treatment since individual conditions make each case unique.
1.Mayfield, R. D., et al. "Genetic Factors Influencing Alcohol Dependence." British Journal of Pharmacology, vol. 154, no. 2, n.d., pp. 275-287. EBSCOhost, ezproxy.shsu.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=edswsc&AN=000255755900003&site=eds-live&scope=site.
The relevant genes that influence a range of intermediate characteristics that are specific to alcohol dependence risk include low sensitivity response to alcohol. This characteristic predicts later heavy drinking and alcohol dependence but not other drugs. Other genetic variations that are specific to alcohol dependence include genes related to alcohol metabolizing enzymes. Alcohol dehydrogenase gene on chromosome 4 specifically seems to have a potential impact also on the dopamine reward system. Other polymorphisms that are possibly associated are the dopamine receptor D4 gene on chromosome 11 and dopamine receptor D2 gene on chromosome 2.
There are genetic factors that appear to have an influence on alcoholism but are not specific to the drug alcohol. There seems to be a correlation between personality characteristics such as impulsivity, sensation seeking, and impaired ablility to learn from mistakes. The GABA A receptor is a major inhibitory neurotransmitter and is reported to be associated with the phenotypes that are related to alcoholism and other addictions as well as mental disorders such as schizophrenia and depression. Schizophrenia and depression are thought to be genetically influenced as mentioned above and these syndromes also enhance the risk for alcohol dependence.
It is still important to note that while there is definitely more progress made in this study and the study of other conditions with a tie to mental conditions there is still a lot that can be analyzed. Also just because there is more evidence that there are genetic aspects that influence addiction, and mental disorders it does not mean that they will develop in the offspring. The environment, culture and attitudes that a person are raised still play a significant role, approximately 40% on the variance of risk in developing a heavy drinking problem. It is important here also to keep in mind that for things like this there may never be able to be a blanket protocol, rule or treatment since individual conditions make each case unique.
1.Mayfield, R. D., et al. "Genetic Factors Influencing Alcohol Dependence." British Journal of Pharmacology, vol. 154, no. 2, n.d., pp. 275-287. EBSCOhost, ezproxy.shsu.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=edswsc&AN=000255755900003&site=eds-live&scope=site.
I found your blog very interesting. In other classes we have talked about twins being separated and either being completely different or the same depending on the environment and culture they were raised in. I know genetics has a big part in how we are but like you said, there are many other factors that that play a significant role in the outcome of offspring.
ReplyDeleteTwins are some of the best things we have when we compare what genes can do to us vs what the environmental cause it. It is seen even though twins have similar genes and can be raised the same, that some have more interest in certain activities vs other ones. I wonder if one twin have tendencies to stay on the left vs the right of another twin and if this small perspective can make a large difference over the years. If there is what is the trend seen.
ReplyDeleteAnyways, as you've found alcohol dependence is a complicated topic and can vary from person to person. Since you mentioned there are different reasons for drinking, each person may have their personality which appeals to that. Those who are risk takers or competitive may drink to push themselves and try to out drink others. I can see how winning these competitions would build up in someones head as a good experience.
IMHO, twin studies can be problematic if there is no attempt to quantify environmental variables that separated twins experience. Nonetheless, identification of specific genes and access to really huge geneaologies have been pretty useful in exploring genetic causes of disease.
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