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SCI/TECH: Progressive Aphasia Syndrome Linked to Prions

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posted on Dec, 10 2005 @ 03:09 PM
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Progressive Aphasia Syndrome (PPA) has been linked to a prion gene variation. PPA is a form of dementia that causes problems in using and understanding language. The specific amino acids linked to PPA are methionine and valine. It is not believed that abnormalities in these amino acids are a primary cause of PPA, but these variations are present in a large number of individuals with the disorder. While this study does contradict previous studies that have linked Alzheimer's Disease to prions, it does not eliminate prions as a cause.
 



www.sciencedaily.com
Most people with a rare type of dementia called primary progressive aphasia (PPA) have a specific combination of prion gene variants, a new study shows. The study is the first to link the prion protein gene to this disorder. It was funded in part by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health (NIH), and appears in the December 2005 issue of the Annals of Neurology.

PPA is classified as a type of frontotemporal dementia because of the pattern of brain degeneration it causes. The primary symptoms of the disease are problems speaking or understanding speech, and these problems gradually get worse over time. People with PPA also may develop difficulty with math. Most other functions remain normal for at least two years after the language symptoms appear, but the disease may eventually cause other changes, such as problems with memory, reasoning, and spatial abilities. While PPA sometimes runs in families, it has never before been linked to variations in a specific gene.

People normally have two copies of every gene. In the new study, Dr. Mastrianni and his colleagues found that almost 85 percent of the people with PPA who took part in this study had one copy of the prion gene coding for the methionine variant and the other coding for valine. "The association between this gene combination and the disease is really dramatic," he says. However, not all people with the two gene variants develop PPA. Therefore the prion gene is probably not the primary cause of the disease, he adds.

The findings conflict with previous studies that found an association between Alzheimer's disease and a specific variant of the prion protein. However, the protein could still play a role in that disease. "We aren't saying there is no link to Alzheimer's disease -- just that there isn't any association with the genetic state of the prion protein gene in our patient sample," explains Dr. Mastrianni.






Please visit the link provided for the complete story.


The prion phenomenon has been somewhat of a bugbear for me, what with so many ailments being linked to these mysteriously deformed proteins. Little by little, the term seems to pop up in discussions ranging from HIV to a variety neurodegenerative conditions. This topic, which was once a source of frustration and confusion for me is becoming a source of excitement in terms of the growth of our understanding of the causes of some of our most misunderstood and debilitating illnesses.

Related News Links:
www.sciencedaily.com
www.sciencedaily.com
www.sciencedaily.com
www.emedicine.com

Related AboveTopSecret.com Discussion Threads:
SCI/TECH: "Mad Cow" Disease Uses Immune System to Spread in Body
Do Prions Exist?


[edit on 2005/12/10 by GradyPhilpott]




posted on Dec, 10 2005 @ 05:14 PM
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Yes Proteomics is definately the future. The Human Genome Project was really just the first phase in learning about the Human body. The Proteomics project is 10,000 times more complex then the HGP.



posted on Dec, 11 2005 @ 07:26 AM
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Great find Grady.


I have a few issues with the way "prion diseases" are explained to the public:

The media invariably focuses on the PrP protein and the so-called "prion gene." PrP is the protein implicated in the few officially-recognized prion diseases that affect the brain directly - but virtually any protein can misfold and become a "prion," not just PrP.

The so-called "prion gene" codes for PrP production, and in some cases, the gene has mutated to (mis)code for misfolded PrP. But - relatively few prion diseases result from a genetic mutation. Prion diseases are recognized to be about 10% genetic, with the rest "sporadic," or "acquired."

So the focus on "genetic susceptibility" is misleading - it ignores 90% of the prion disease cases that are diagnosed and recognized as such - and dismisses outright the huge number of prion-related diseases that are not acknowledged officially. As Dr. Mastrianni explains, "We aren't saying there is no link to Alzheimer's disease -- just that there isn't any association with the genetic state of the prion protein gene in our patient sample."

IMO - we are better off looking at the various contaminations in our environment that cause proteins to misfold - rather than focusing on the downstream "genetic" effects related exclusively to the so-called "prion gene" - a red herring IMO.


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[edit on 11-12-2005 by soficrow]



posted on Dec, 11 2005 @ 10:46 AM
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Originally posted by soficrow

IMO - we are better off looking at the various contaminations in our environment that cause proteins to misfold - rather than focusing on the downstream "genetic" effects related exclusively to the so-called "prion gene" - a red herring IMO.


This is a subject I am largely ignorant of Soficrow, so for my education could you please discuss some of the factors (especially environmental) which cause proteins to misfold.



posted on Dec, 11 2005 @ 06:16 PM
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Originally posted by Astronomer68

Originally posted by soficrow

IMO - we are better off looking at the various contaminations in our environment that cause proteins to misfold - rather than focusing on the downstream "genetic" effects related exclusively to the so-called "prion gene" - a red herring IMO.


This is a subject I am largely ignorant of Soficrow, so for my education could you please discuss some of the factors (especially environmental) which cause proteins to misfold.


Changes in the environment can cause proteins to misfold - including temperature changes, chemical and radiation exposures, and electromagnetic pulses. The process sometimes is multifactorial, other times it's strictly a matter of timing. Depends. Here are few links that outline some basics.

A good basic overview of protein misfolding, with good links.

In stressed environments, proteins can unfold, misfold, or aggregate.

Folding happens suddenly at a special temperature for each protein.

"We hypothesized that if something as minor as a slight temperature change could affect which misfolded form the prion went into, if we could slow down which folding route the prion took, we could change the specificity of its infectivity,"

HOW DO PROTEINS FOLD, UNFOLD AND MISFOLD?

Protein folding and disease
For proteins to function properly, they need to fold into the correct shape, and protein misfolding is thought to underlie many diseases, including Alzheimer's disease, Parkinson's disease, new variant CJD and type II diabetes. This meeting brought together an international panel of experts to discuss current thinking on protein folding research, from basic cell biology to therapeutic strategies for treating protein folding diseases.

Unfortunately, the stops along the route of protein folding are much harder to probe than its end point, as the intermediate forms of a protein are, by definition, myriad, unstable and fleeting.

Low temperature or GroEL/ES overproduction permits growth of Escherichia coli cells lacking trigger factor and DnaK

...unlike viruses and other infectious agents, prions withstand ultraviolet light, ionizing radiation, sterilizing temperatures and chemical disinfectants. ...They don't contain genetic material, which means prions don't have a biological target that can be easily attacked by drugs or vaccines.

PROTEIN FOLDING/STABILITY IN VIVO AND IN VITRO

Nanoscale hydrophobic interaction may be important in protein folding and thermal stability.

Current progress suggests that hydrogen-bond formation dominates RNA folding. More broadly, extensions of folding studies may allow understanding of the formation of protein aggregates involved in illnesses (such as Parkinson's) connected with misfolding.


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posted on Dec, 11 2005 @ 11:24 PM
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Thank you very much Soficrow. I will probably be cross-eyed for the next month as I have been following the links you provided ever since you posted them for me. The material is absolutely fascinating and studies underway or planned are incredibly important to our understanding of how we ourselves are made and function. I probably have another year or so of reading to get to a state where I can intelligently discuss this subject. Again, thank you.



posted on Dec, 12 2005 @ 03:50 PM
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Originally posted by Astronomer68
Thank you very much Soficrow.


You're welcome.




I will probably be cross-eyed for the next month as I have been following the links you provided ever since you posted them for me. The material is absolutely fascinating and studies underway or planned are incredibly important to our understanding of how we ourselves are made and function. I probably have another year or so of reading to get to a state where I can intelligently discuss this subject. Again, thank you.


Good for you. Keep reading.


...A lot of prion info is breaking into the public domain now - it will get much easier to understand once it's all out in the open. Right now, it's hard because prions break so many "rules" and we all have to rethink our assumptions - and throw out so much of what we've been taught.


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