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Comment on CRISPR used to remove extra chromosomes in Down syndrome and restore cell function

This is not true on multiple levels. One of the benefits of the Crispr technique is it can be used in vivo, so this sort of treatment will potentially be able to be used at any point in an individual’s life. But also, trisomy-21 isn’t present in sperm or eggs, it’s a mistake in cell division early in fetal development, so applying this technique to an egg would have no purpose or effect.

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dondelelcaro@lemmy.world ⁨19⁩ ⁨hours⁩ ago

trisomy-21 isn’t present in sperm or eggs, it’s a mistake in cell division early in fetal development

This is incorrect. Non-disjunction (where chromosomes incorrectly separate) typically happens during the formation of egg or sperm. (We know this because most everyone with down syndrome has three different chromosome 21 instead of two identical copies of one chromosome.)

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- protist@mander.xyz ⁨18⁩ ⁨hours⁩ ago
  TIL
  
  In the majority of cases, the extra copy of chromosome 21 comes from the mother through the egg.
  
  In a small percentage (less than 5%) of cases, the extra copy of chromosome 21 comes from the father through the sperm.
  
  In the remaining cases, the error occurs after fertilization, as the embryo grows.
  
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