
Scientists discover the chemicals behind the unique Parkinson’s smell - jkuria
https://www.economist.com/science-and-technology/2019/03/30/scientists-discover-the-chemicals-behind-the-unique-parkinsons-smell
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dcomp
It would be interesting to see whether this smell is caused by the same thing
that results in Parkinson's or just associated with it.

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tuukkah
Similar to yesterday's news: "Dogs demonstrate the existence of an epileptic
seizure odour in humans"
[https://news.ycombinator.com/item?id=19521835](https://news.ycombinator.com/item?id=19521835)

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radosc
It calls for some company to create an efficient electronic nose. Build a
database of disease markers, save lives, and say farewell to the health
condition privacy.

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kazinator
In future job interviews, you will be surreptitiously sniffed by electronic
devices that estimate whether you might be a liability to the health insurance
group plan or a frequent absentee who uses up all the paid sick days.

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christopher8827
To get around the paywall;
[https://outline.com/8M4RL7](https://outline.com/8M4RL7)

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etaioinshrdlu
Maybe smell detection will bring us the future Theranos imagined.

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guru_meditation
November 15, 2018 publication:

Discovery of volatile biomarkers of Parkinsons disease from sebum

[https://doi.org/10.1101/469726](https://doi.org/10.1101/469726) (free full-
text PDF link on site)

From the abstract:

We have serendipitously identified a hyperosmic individual, a Super Smeller
that can detect Parkinson's Disease(PD) by odor alone, and our early pilot
studies have indicated that the odor was present in the sebum from the skin of
PD subjects.

~~~
lvs
Thanks for the actual paper. No authentic standards were used to validate the
assignments. These are being identified by low-resolution single-quad mass
alone. The chances that these compounds, if they exist, are correctly
identified is very small. For point of comparison, they also found artemisinic
acid, an antimalarial drug precursor that is not typically administered in the
UK -- and not as the precursor.

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mikekchar
Odd... The page doesn't load for me and I end up at a Facebook error page...

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gordaco
This is exciting for two reasons. First, we could develop a measurable
diagnosis based on this. Second, we can now search for the source of these
chemicals and use them to better understand this illness, and that might lead
to a cure.

I love when people use these small time superpowers for tho good of everyone.

~~~
viraptor
Does anyone know how close are we at the moment from being able to say "we're
getting X smell, so here are the genes producing X producers"? I know we can
(most of the time) say, here are the sites producing a specific protein. But
are we able to find sites for second and higher order results yet?

~~~
dkural
It's luck of the draw. We understand perhaps 15-20% of the genes/proteins in
the human genome fairly well. We have fairly general notions of what the rest
are but lack specific understanding. We also discover novel functions for
genes/proteins we thought we knew well.

One way to discover function is to what's called a "genetic screen": Assuming
one develops a robust way of measuring those chemicals; we fix that as the
"phenotype" we're looking for. We can then disable each gene (with CRISPR, or
RNAi, or chemical mutagenesis..) and see if the chemicals get produced (or
stop getting produced); and then sift through those. This strategy is far from
being exhausted; and people keep coming up with cool phenotypes to measure.

One idea I've been excited for some time is using ML to robustly annotate
behaviors from mice by using wide-range microphones and 24/7 video as the
phenotype; and use a combinatorial genetic screen to rigorously discover
genetic contributors to behavior (aggression, mobility, curiosity, socializing
behavior etc.) The ML algorithm can be initially trained by hand-annotated
behaviors (annotated by post-docs etc.)

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abhinai
_Smell_ represents an entirely new approach to medical diagnosis and in the
next decade god knows how many tests we'd be able to develop using this
approach. I am truly excited!

~~~
lazyjones
> _Smell represents an entirely new approach to medical diagnosis_

It's not new at all. Traditional Chinese medicine has used it for a long time,
among others.

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GuyGriffin
Any examples of TCM / smell patterns?

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gonesilent
[https://www.youtube.com/watch?v=5ok3EZnpaD4](https://www.youtube.com/watch?v=5ok3EZnpaD4)

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sidcool
Parkinson's, Alzeimers and other neurological disorders will be cured in the
future. What bothers me is that people from past and present will continue to
suffer until then. We need to support scientists more.

~~~
melling
Within the next 150 years, we’ll probably turn most diseases into something
treatable as we slowly acquire knowledge.

Of course, imagine if we started rapidly acquiring knowledge, I’d be saying
within 75 years.

Your choice.

~~~
Consultant32452
I wonder if "science" generally suffers the same plight that is discussed in
The Mythical Man Month. I suspect it does.

~~~
melling
So, you think science one big problem that we’re trying to solve?

Personally, I’d say it’s more like millions of smaller problems.

~~~
Consultant32452
It's not clear that doubling the research funding from the NIH results in
twice as much qualitative output. That's all I mean.

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rectang
> _perillic aldehyde, hippuric acid, eicosane and octadecanal_

It's tantalizing to see the names fixed in print. To make a software dev
analogy, it's like finally reproducing a heisenbug and knowing it's very
likely you'll find the root cause soon.

~~~
dustindiamond
What is a heisenbug?

~~~
pdpi
It’s a riff on Heisenberg’s uncertainty principle — a bug that changes
behaviour when you try to observe it, typically the sort of bug that you can’t
reproduce under debug conditions. Often they’re race conditions or other
timing-sensitive bugs, and the debugger changes timings enough that the bug
doesn’t trigger.

~~~
Consultant32452
I fondly remember a bug that only appeared when print statements were removed.
The i/o of the system out was just long enough for some buffer to clear,
making the app work. That was very annoying.

~~~
aloer
earlier today I had a problem with Xcode always opening the wrong file, a
README

Turns out I am not the only one:
[https://stackoverflow.com/questions/53132398/xcode-10-1-open...](https://stackoverflow.com/questions/53132398/xcode-10-1-opening-
wrong-file)

half a year old at least, as long as the first file is a readme it will open
that one instead of the actually clicked file in a new window no matter what.
Only fix is to remove the file

but if Xcode is instead set to open as new tab instead of new window, instead
everything works just fine.

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chrischen
EDITED: She can also smell Alzheimer's, even before a person is about to
develop it.

[https://www.express.co.uk/life-
style/health/1107030/dementia...](https://www.express.co.uk/life-
style/health/1107030/dementia-life-woman-smell-husband-Alzheimer-strange-
odour)

~~~
maxerickson
_But her sensitivity to smell means she is unable to enter the cleaning
products aisle in supermarkets. To most people, the plastic packaging has no
odour; to Joy, it is so intense she starts to retch._

Is that even remotely true that people can't smell that aisle? I don't think I
have an extraordinary sense of smell and I think of the smell of that aisle as
"rank" or something like that.

~~~
amelius
I think I can smell that aisle, but it's from the detergent, not the plastic.

~~~
tapland
I think that distinction in the text was not the intended point. With 'the
plastic' they mean the products, not the plastic packaging. Because of it was
the packaging, made of common materials, entire supermarkets would be off
limits.

And no, I don't think most people feel no smell in the cleaning aisle.

~~~
coroxout
I guess they mean that most people can smell freshly sprayed cleaning products
but think the products don't smell of much when still in the bottles.

The aisle has a faintly bleachy/detergenty smell to me, but not usually
oppressive, more just pleasantly clean, I suppose.

But I have noticed my hands/sweat smell different when I have a cold, and
sometimes a day or two before I feel ill. I usually only get close enough to
notice it on my own body, but I have a couple of times entered someone else's
room/office and smelt the same smell before hearing confirmation from their
croaky voice, snuffling, or them just telling me they have a cold.

(And no, it's not the smell of cough sweets or lemon/honey-based cold
remedies, but it might be partly the smell of damp tissues and stale phlegm
and other such nice things. Subtle but sickly sweet.)

Obviously this is neither particularly useful nor a superpower, but I'm glad
research is going on into more useful applications of similar phenomena.

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bookofjoe
First epilepsy (dogs), now Parkinson's. Leads me (retired neurosurgical
anesthesiologist) to wonder if ALL pathology has an olfactory component that,
with sufficient sensitivity of instrumentation, can be detected. Perhaps we
won't require a "Star Trek"-type imaging device: just stand still and let the
mass spectrometer do its thing.

~~~
anisppp
Wow so 2 _whole_ things are able to be identified by volatile chemicals and
this leads to all?!

And I wonder how people like Holmes are able to survive for >10 years. We can
deliver nicotine via patch, so obviously _all_ drugs should be delivered that
way. We can measure glucose from a drop of blood so obviously it follows that
_all_ blood tests run that way.

Where is the evidence that even a small fraction of the most common diseases
have such a characteristic?

~~~
bitexploder
He was just speculating. Also, dogs can smell cancer in humans.

~~~
anisppp
Dogs have been shown to detect certain cancers at later stages (which greatly
limits use as a screener.. not to mention how does the sensitivity/specificity
compare to state of the art). This is not surprising since as cancers advance
they cause gross biochemical changes.

The further issue diagnosing cancer/no cancer or epilepsy/no is an easy
problem. But train a dog/machine on 1000 or more rare diseases. Now
selectivity is an actual issue. And unless you manage to overcome that, how is
all this scent stuff clinically useful?

~~~
hobs
So the original "sniffer dog" study (The Lancet 8640)[0] pretty much covers a
dog sniffing out a melanoma BEFORE it got to a later stage, and saved a
woman's life.

I also dont understand how training a machine would have selectivity issues.
Machines dont "get trained" on one thing.

0:
[https://www.sciencedirect.com/science/article/pii/S014067368...](https://www.sciencedirect.com/science/article/pii/S0140673689922575?via%3Dihub)

~~~
tepper09
That is not a study. That is a case report written as a letter to the editor.
That meets no scientific rigor at all and no generalizable conclusions can be
drawn from it, it provides an anecdote for further research. It also doesn’t
suggest that sniff tests would fare better compared to any other screening
system for melanoma.

