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

bonsai_spool

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 patient and is unlikely to be used as a treatment paradigm, but the biological approach is clever. [1] https://www.pnas.org/doi/10.1073/pnas.2517953123

memonkey

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, for example. There are ongoing philosophical discussions of whether or not these technologies and scientific discoveries are actually harming or helping those with these disabilities and the broader discussion of 'normalizing' society at large (I don't want to use the term eugenics).

Metacelsus

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.

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