The Genetic Origins of Alcoholism & Obesity

Obesity and Alcoholism are both deadly disorders that don’t often gain adequate attention from the public eye. The term obesity is commonly tossed around as a synonym for fat or overweight and is dismissed as nothing more than an unhealthy condition. Alcoholism is tucked under the umbrella of addiction, an umbrella that can get overshadowed by more predominant diseases such as cancer. With the minimal public understanding of both disorders, it is unsurprising that many people don’t know of underlying genetic factors that may not only contribute to both these disorders separately but also tie them together in a rather deleterious combination.

Illustration by Andrea Mongia

Firstly, let’s clear some things up and talk about why these diseases deserve more regard.

According to the Centers for Disease Control and Prevention (CDC), an average of 6 people die every day due to alcohol poisoning. According to the World Health Organization (WHO), at least 2.8 million people die each year of being obese while. How? Obesity is the condition of having too much body mass, much beyond that of an overweight person; this extremely unhealthy amount of mass creates an increased risk of developing dangerous diseases such as diabetes, myocardial infarction, and certain forms of cancer. As for alcoholism, it causes more than just the popular conception of liver damage. Our bodies deteriorate under excessive alcohol consumption; from ineffective intestines, lung infections, thinning bones, and heart damage, just to name a few. The harmful results of both obesity and alcoholism make them incredibly dangerous diseases.

Recently, scientists have observed a unique similarity between the two diseases: a strong association with the gene, GABRA2. A genetic study by Zai et al. 2015 discusses the correlation of this gene with obesity as identified by genome-wide association studies (GWAS). GWAS is a research tool used by scientists to scan genomes and pinpoint various correlations. GABRA2 has also been tied to substance abuse disorders such as alcoholism. Trucco et al. 2014 explains this through the idea of rule-breaking – an important factor that contributes to addiction. The study describes how GABRA2 facilitates rule-breaking which, in turn, leads to increased substance abuse such as alcoholism.

So what exactly is GABRA2 and what does it code for? This gene is one of many that code for something known as GABA receptors. These brain receptors sustain different niches in our bodies, ones that are rightly affected by both alcoholism and obesity. They are inhibitory neurotransmitters: biochemical substances that reduce the likelihood of neurons firing an action. Alcohol is believed to mimic this effect by interacting with these receptors; that’s the reason behind the slow and rather uncoordinated movements from intoxicated people. Interestingly, GABA receptors are also involved in satiation and body weight regulation – our obvious connection to obesity.

“Genes are incredibly complex and it’s rare to find a single gene that codes for a single function without any other influence.”

The functions of GABA receptors explain the relationship between the gene that codes for them, GABRA2, and alcoholism and obesity. However, genes are incredibly complex and it’s rare to find a single gene that codes for a single function without any other influence. Single Nucleotide Polymorphisms (SNPs) are one such factor that plays a huge role in the complexity of genes. An SNP is essentially a change in a single nucleotide, a building block, of the gene sequence; a single gene may have numerous such variants. So while the GABRA2 gene seems to be associated with both alcoholism and obesity, it’s likely that the SNPs of the gene are different between the two.

The big takeaways from these results is the role of susceptibility and prevention. We now have a rough idea of a probable genetic origin of obesity and alcoholism; this definitely requires more research in order to solidify the genetic connection. We can then utilize this information as a potential early risk factor and implement appropriate prevention practices.

What do you think about these genetic associations? Do you think future genetic studies would be successful at confirming disease origins? Let us know in the comments below!


References

Trucco EM, Villafuerte S, Heitzeg MM, Burmeister M, Zucker RA. Rule breaking mediates the developmental association between GABRA2 and adolescent substance abuse. Journal of Child Psychology and Psychiatry. 2014Sep;55(12):1372–9.

Zai CC, Tiwari AK, Chowdhury NI, Brandl EJ, Shaikh SA, Freeman N, et al. Association Study of GABAA α2 Receptor Subunit Gene Variants in Antipsychotic-Associated Weight Gain. Journal of Clinical Psychopharmacology. 2015;35(1):7–12.

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