
Eye test may detect Parkinson’s before symptoms appear - renafowler
http://sciencebulletin.org/archives/4448.html
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coetzeesg
There is some evidence that the brain (and substantia nigra) is not the only
region where risk for Parkinson's can accumulate. There may be some ties to
developmental processes, lymphocytes, and the liver and fat cells[0].

[0][http://www.nature.com/articles/srep30509](http://www.nature.com/articles/srep30509)
[0][http://parkinsonsnewstoday.com/2016/08/11/parkinsons-risk-
mu...](http://parkinsonsnewstoday.com/2016/08/11/parkinsons-risk-mutations-
impact-brain-least-of-all/)

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nickledave
Hmm. In your studies can you identify retinal tissue? Guessing not since it's
such a relatively small amount and might not have a clear marker like
adipose/liver tissue.

Accumulating mutations could _cause_ Parkinson's--some sort of inflammatory
syndrome from altered metabolic pathways, you can probably explain it better
than me--but the study in OP seems to be suggesting retinal degeneration is a
_symptom_ , right? Maybe retinal tissue could be a "canary in the coal mine"
because it's more sensitive to these changes in metabolism? I'd be interested
to know what you think.

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coetzeesg
Yea, I can only work with tissues that I have chromatin marks for, and retinal
tissue is not one that is easily available. But it's possible that the retinal
features are an early detector of disregulation (in some pathway to
Parkinson’s), and it would be interesting to see precisely what it’s
detecting, perhaps shedding more light on inherited risk.

~~~
nickledave
Ah, it's chromatin marks you need. Well I guess you could get a lot of retinal
tissue from the rat model they use and try to find some. Interesting that this
finding is in an animal that doesn't depend as much on vision as we do. Might
be worth determining if the result holds up in e.g. a macaque model.

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dannylandau
I can't tell if this report is vapor research or there is something of merit.
For example, if only tested on mice, then how is this related to Parkinson's
Disease, can anyone clarify?

~~~
nickledave
The results in the research article were obtained with a rat model of
Parkinson's, where Parkinsonian symptoms are induced with rotenone. Most
models of Parkinson's are based on neurotoxic drugs (e.g. MPTP, first
discovered to induce Parkinsonian symptoms in heroin addicts) so they're kind
of the best we can do. (there's also genetic models--e.g. mice that express
chronically low levels of dopamine. But basically other animals don't get
Parkinson's in the wild as far as we can tell.) There's a summary of the
evidence for the rotenone model in the discussion of the paper itself, and the
paper is in an open access journal so you can read it should you so desire:
[http://actaneurocomms.biomedcentral.com/articles/10.1186/s40...](http://actaneurocomms.biomedcentral.com/articles/10.1186/s40478-016-0346-z)

There is something of merit here if there's any reason to believe that actual
Parkinson's patients show similar retinal degeneration far before they show
any other symptoms. The authors don't mention any evidence for that...so I'm
guessing there's not any. Either they are wildly scrambling to find some, or a
cynic might suggest they looked already in humans and didn't find any, so they
published this instead. A paper showing multiple lines of evidence supporting
their theory in a rodent model and in a patient population would probably have
been a home run that got them into a glam mag.

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feld
I wonder if this is muscle twitching similar to the claim of detection just by
voice over the phone

