Scientists studying Andersen's disease had given a name to such deposits or molecules, calling them polyglucosan bodies.
Polyglucosan bodies is caused by a deficient Glycogen Branching Enzyme 1 gene (GBE1) that originally encodes for a 702 amino acids long, monomeric protein (2106 base pair mRNA) which makes a fully functional GBE. Since GBE is essential for making glycogen, a mutation to this gene would result in making abnormal glycogen molecules.
This mutation may or may not cause Adult Polyglucosan Body Disease (APBD) as scientist are still unsure of the mechanisms of the disease itself.
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| May or may not cause APBD? Sounds oddly familiar... Psst Google Schrodinger's Cat if you don't understand this meme! It's quite interesting.... (so I say) |
What exactly is a GBE1 mutation?
It results in APBD which is a condition that affects the nervous system due to major loss (not entirely!) of the GBE1 gene function. At least 3 mutations in the GBE1 gene that causes APBD is known to scientist.
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| Located on the short (p) arm of the chromosome of chromosome 3 is GBE1 gene, which is essential for proper branching of glycogen. |
A version of the mutation is often seen in Ashkenazi Jewish ancestry is that the amino acid tyrosine (tyr) is replaced with the amino acid serine (ser) at the 329th amino acid. This leads to a deficient GBE1. So what's the big deal you ask? Well, it leads to polyglucosan due to lack of branching of glycogen which in turn leads to accumulation of polyglucosan bodies which are capable of causing cell damage.
Scientist found out that neurons are more susceptible to the accumulation of polyglucosan bodies which leads to damaged neurons that can result in decreased sensation, vulnerability and other nervous systems disorders - most of which are symptoms of APBD.
"Erm I thought your topic was on Andersen's disease?... I don't see the link here..."
As mentioned above, at least 3 mutations in the GBE1 gene leads to APBD but for Andersen's disease, a whopping amount of approximately 40 mutations in the GBE1 gene had been characterized by scientists. Single amino acids mutations also occur which results in the same accumulation of polyglucosan bodies.
However, instead of targeting the neurons, Andersen's disease affects mostly the liver and muscle cells due to complete loss of enzyme activity instead of a partial loss like in APBD. Accumulation of glycogen leads to inability of your liver to function and coupled with the fact that your muscle cells are unable to break down "glycogen" for glucose (main source of energy), it leads to fatigue, enlarged liver, muscle weakness and most of the symptoms of Andersen's disease.
Although scientist do know that these 2 diseases affect different part of the body, they are still unsure of the exact reason why this happen.
I guess it must be frustrating to not have an end answer to their problems and questions. But science is always about a collective effort of finding out the truth! Hopefully with further research, it will be able to shed some light on the issue...
Apologies for the extremely long post, but I hope we've given you some extra knowledge to take home and digest!
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| Some ice cream to make up for the long post! |
Sources:
https://americanwicca.files.wordpress.com/2012/06/funny-pictures-schrodingers-cat-chemistry-cat.jpg?w=250
http://themedicalbiochemistrypage.org/andersendisease.php
http://ghr.nlm.nih.gov/gene/GBE1
http://ghr.nlm.nih.gov/dynamicImages/chromomap/GBE1.jpeg
http://www.slideshare.net/BenDecker/molecular-characterization-of-polyglucosan-body-cause-or-consequence-in-the-disease
http://biggapon.com.bd/wp-content/uploads/2014/12/andersens2.jpg
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