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Gene correction. Human 2 PN model. Ma 2017 concerns
Genome editing occurred essentially exclusively using the normal maternal chromosome as a template? This is unlikely because the male and female pronuclei are entirely physically separated in the 1-cell embryo.
Apparent absence of a detectable mutant allele? The altered (not repaired) mutant alleles are there but just not detectable.
Zygoteswithasinglepronucleusarenotuncommon
after intracytoplasmic sperm injection, occurring in ~10% of fertilization attempts, and are mostly of parthenogenetic origin, containing only the maternal genome
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Inter-homologue repair in fertilized human eggs? PCC Genetics - ESHRE BCN 2018
Gene correction. Human 2 PN model
First study using base editor (BE) system to correct disease mutant in human embryos.
Base editor could precisely correct HBB −28 (A>G) mutation in the patient’s primary cells.
To model homozygous mutation disease embryos, nuclear transfer embryos by fusing lymphocyte or skin fibroblast cells with enucleated in vitro matured (IVM) oocytes were constructed.
The gene correction efficiency was over 23.0%
Although these embryos were still mosaic, the percentage of repaired blastomeres was over 20.0%.
BioRXiv Egli et al, 2017
Correction of β-thalassemia mutant by base editor in human embryos Protein Cell , Liang et al, 2017
PCC Genetics - ESHRE BCN 2018
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