Once you have a multicellular animal, it's far too late. You have to do the gene editing before cell division occurs. You can't ensure delivery or uniform uptake otherwise. And beyond this, delivery itself is incredibly hard. You can't get eukaryotic cells to uptake genes.
> You can't ensure delivery or uniform uptake otherwise
That's all true (and I agree), but that's a practical/technical issue. That may be solvable, but even in that case, that's not the whole story. There are also developmental biology issues at play once you have a full organism (or even an embryo that is just a few cell divisions in). The way our bodies operate as adults is just as much a function of how our cells developed and grew as it is a product of genetics. There are a lot of processes that happen only at very specific timepoints in development. And once you're past those points, editing the genes required won't have any phenotypic effect.
We can alter genetics with CRISPR. We can't alter morphology in the same way. For example, in certain eye diseases, you can have a loss of a gene that is involved in how the retina processes light. But, the same gene is also involved in how the optic nerve is formed (or migrates) in the brain. You could use gene editing approaches to knock in a good copy of the gene, which might help the retina absorb light, but the nerves have already formed and are already in place. That isn't going to change.
And none of that actually addresses the ethics involved in changing the genetics of a person, which is non-trivial to say the least.
I am not a biologist, but I doubt that. If you want to do this to an embryo, then abortion is a much saner option option.
Doing this a a living person would be pure madness, given the fact that we can't yet CRISPR even simple edits and deleting a chromosome (how would you even target just one of the copies?) is something much more complicated.
the first daunting task is editing trillions of cells. rough estimates [0] put the number of cells in the body at 37 trillion, with about 80% of those being red blood cells (who've lost their nuclei), so that puts the number of intact-nuclei cells at ~7.5 trillion. how many of those would you have to edit to mitigate such a syndrome?
even if you could edit the critical cells, you'd end up with a chimeric cell makeup, and what does that mean in the long-term? then you have to tackle ethics, psychological effects, physiological effects, etc.
not trying to squelch the thought or effort, but that seems like a very long, hard road.
