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CRISPR takes important step toward silencing Down syndrome’s extra chromosome

medicalxpress.com

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Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#61

Post by sheept »

bonsai_spool wrote: post #27

This is very clever - the X chromosome has a mechanism to shut itself down (which makes sense; otherwise cells in women would have twice as many gene products from the X chromosome as cells from men). The linked research report[1] uses that mechanism, Xist , to shutdown chromosome 21, the extra chromosome whose presence causes Down syndrome. In its present form, it would need to be optimized for each potential patien…

> the X chromosome has a mechanism to shut itself down (which makes sense; otherwise cells in women would have twice as many gene products from the X chromosome as cells from men).

You can see this visually because not the same X chromosome is deactivated in all cells: it's what gives calico cats their color (almost all of them are female).

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#62

Post by eucyclos »

pixel_popping wrote: post #13
JimmyBuckets wrote: post #2

[flagged]

99% doesn't make sense, not even 99% of people without Down syndrome are happy (far from it I believe).

I'm pretty sure abnormally low levels of neuroticism is a symptom of Downs syndrome. Not a doctor but I've interacted with several. The only neurotypical people who are that happy are Buddhist monks.

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#63

Post by hgoel »

memonkey wrote: post #46

I am slightly reminded of Gattaca, the story of which is that certain people are discriminated based on their DNA. Society is built, in general, excluding certain people due to their disabilities. Whether or not a blind person can find meaning or enjoy life has road blocks but is not impossible. Science can provide technologies to potentially improve people's lives -- cochlear implants for those with hearing loss, fo…

Recognizing that certain mutations very blatantly reduce a person's quality of life and making it possible to revert those mutations does not require treating the people who have not had those mutations reverted as lesser.

Thinking of them as lesser leads to a society that prefers to drag each other down instead of lifting each other up.

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#64

Post by dreamcompiler »

sheept wrote: post #61
bonsai_spool wrote: post #27

This is very clever - the X chromosome has a mechanism to shut itself down (which makes sense; otherwise cells in women would have twice as many gene products from the X chromosome as cells from men). The linked research report[1] uses that mechanism, Xist , to shutdown chromosome 21, the extra chromosome whose presence causes Down syndrome. In its present form, it would need to be optimized for each potential patien…

> the X chromosome has a mechanism to shut itself down (which makes sense; otherwise cells in women would have twice as many gene products from the X chromosome as cells from men). You can see this visually because not the same X chromosome is deactivated in all cells: it's what gives calico cats their color (almost all of them are female).

Human women have stripey skin too, but you can't see it under normal light because unlike cats, skin tone in humans is not controlled by the X chromosome.

https://www.youtube.com/watch?v=BD6h-wDj7bw&t=225s

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#65

Post by TurdF3rguson »

hgoel wrote: post #63
memonkey wrote: post #46

I am slightly reminded of Gattaca, the story of which is that certain people are discriminated based on their DNA. Society is built, in general, excluding certain people due to their disabilities. Whether or not a blind person can find meaning or enjoy life has road blocks but is not impossible. Science can provide technologies to potentially improve people's lives -- cochlear implants for those with hearing loss, fo…

Recognizing that certain mutations very blatantly reduce a person's quality of life and making it possible to revert those mutations does not require treating the people who have not had those mutations reverted as lesser. Thinking of them as lesser leads to a society that prefers to drag each other down instead of lifting each other up.

I don't know about this argument because they seem a lot happier than I am.

That's not to say that it's unreasonable to value intelligence over happiness, but framing it as quality of life seems off.

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#66

Post by shevy-java »

After skimming through, one obvious question follows:

How can they ensure that (only) one out of three chromosomes only, have XIST integrated? (I assume they can target these three chromosomes due to the CRISPR RNA.)

So down syndrome is trisomy 21, aka three chromosomes 21. Say you have to modify a billion cells, just to give a number. Well, how can you ensure that all those have one XIST gene that is also active (otherwise it would be pointless; XIST produces a RNA which in turn silences the X chromosome by coating it)? Inserting new genes is nothing new, that is already ancient technology at this point in time.

https://en.wikipedia.org/wiki/XIST

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#67

Post by shevy-java »

bonsai_spool wrote: post #27

This is very clever - the X chromosome has a mechanism to shut itself down (which makes sense; otherwise cells in women would have twice as many gene products from the X chromosome as cells from men). The linked research report[1] uses that mechanism, Xist , to shutdown chromosome 21, the extra chromosome whose presence causes Down syndrome. In its present form, it would need to be optimized for each potential patien…

And how do they ensure that only one X chromosome is inactivated? All three X chromosomes are, for the most part, equal, neglecting differences between father and mother X chromosome and changes during meiosis.

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#68

Post by shevy-java »

dreamcompiler wrote: post #64
sheept wrote: post #61

Earlier quoted context omitted.

> the X chromosome has a mechanism to shut itself down (which makes sense; otherwise cells in women would have twice as many gene products from the X chromosome as cells from men). You can see this visually because not the same X chromosome is deactivated in all cells: it's what gives calico cats their color (almost all of them are female).

Human women have stripey skin too, but you can't see it under normal light because unlike cats, skin tone in humans is not controlled by the X chromosome. https://www.youtube.com/watch?v=BD6h-wDj7bw&t=225s

Can you link to a scientific article? I have severe doubts about that claim made on a random youtube video. In fact, I'd go as far as to claim that the content of the words here, are not correct. This is why I think a doi link to a research paper is necessary. I don't doubt that individual cells are, of course, chimeric, but I doubt the "stripey skin" claim. That one makes zero sense.

I just did a google search and this further confirms my suspicion. Thus I would like to ask for a link to a scientific article - until that happens I remain rather unconvinced.

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#69

Post by shevy-java »

Metacelsus wrote: post #55

If they're going to all that effort to make allele-specific guides why not just cut out the centromere and eliminate the chromosome entirely? This seems like an overly complicated solution.

But this has the same problem as before - how can you ensure that only one X-chromosome is killed off? Or at the least one?

Re: CRISPR takes important step toward silencing Down syndrome’s extra chromosome

#70

Post by rendaw »

dreamcompiler wrote: post #64
sheept wrote: post #61

Earlier quoted context omitted.

> the X chromosome has a mechanism to shut itself down (which makes sense; otherwise cells in women would have twice as many gene products from the X chromosome as cells from men). You can see this visually because not the same X chromosome is deactivated in all cells: it's what gives calico cats their color (almost all of them are female).

Human women have stripey skin too, but you can't see it under normal light because unlike cats, skin tone in humans is not controlled by the X chromosome. https://www.youtube.com/watch?v=BD6h-wDj7bw&t=225s

That video seems to imply you can't see it under any light and the image there is pure visualization.
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