Genome editing has potential for the targeted correction of germline mutations. Here we describe the correction of the heterozygous MYBPC3 mutation in human preimplantation embryos with precise CRISPR–Cas9-based targeting accuracy and high homology-directed repair efficiency by activating an endogenous, germline-specific DNA repair response.
Induced double-strand breaks (DSBs) at the mutant paternal allele were predominantly repaired using the homologous wild-type maternal gene instead of a synthetic DNA template. By modulating the cell cycle stage at which the DSB was induced, we were able to avoid mosaicism in cleaving embryos and achieve a high yield of homozygous embryos carrying the wild-type MYBPC3 gene without evidence of off-target mutations.
The first known attempt at creating genetically modified human embryos in the United States has been carried out by a team of researchers in Portland, Oregon, MIT Technology Review has learned. The effort, led by Shoukhrat Mitalipov of Oregon Health and Science University, involved changing the DNA of a large number of one-cell embryos with the gene-editing technique CRISPR
To date, three previous reports of editing human embryos were all published by scientists in China.
Now Mitalipov is believed to have broken new ground both in the number of embryos experimented upon and by demonstrating that it is possible to safely and efficiently correct defective genes that cause inherited diseases.
One week later, additional details emerge.
Shoukhrat Mitalipov and his colleagues from Oregon Health and Science University have successfully used the CRISPR Cas9 gene editing technology to wipe out a genetically inherited heart mutation in embryos.
Mitalipov and his colleagues were able to avoid the previous mistakes made by the Chinese scientists by injecting the Cas9 enzyme (which acts as a sort of scissors for DNA fragments) into the sperm and eggs at the same time.
What an incredible moment in history to witness.