Researchers are scrutinizing the limited data made available after He Jiankui's revelation last month that he edited the genomes of two newborns, the Wall Street Journal writes.
He announced that he used the CRISPR-Cas9 gene-editing tool to alter the CCR5 genes in embryos from couples in which the father had HIV, work that he said led to the birth of twin girls. With this edit, He said, the girls could be immune to HIV infection. Critics noted that this brings up ethical concerns, as there are other, simpler ways to prevent HIV infection and that the consequences of turning CCR5 off in every cell is not clear.
However, the Journal adds that He might not have been fully successful in his editing attempt. He presented his work at the International Human Genome Editing Summit, and it says researchers have been poring over and discussing the available data since then, including at a meeting at Harvard University. The Broad Institute's Feng Zhang, who was at the summit, told the Harvard meeting that He seems to have been unable to make the CCR5 edits in every cell, meaning the children may be mosaic, the Journal says. Further, David Liu, also from the Broad, notes that the alterations made were not well-studied ones variants and their effects could differ from the more well-known ones.
"The two frame-shifted variants will encounter early stop codons during translation that will lead to truncated proteins. But even these truncated variants are not necessarily biologically inert," Liu told GenomeWeb. "And the variant lacking five amino acids should really be characterized before creating a baby who has to live with this variant (and whose descendants would as well)."
He has said his work has been submitted to a journal — which may bring up ethical issues for journals — and Zhang says a closer inspection of the data may then answer some of the community's questions. But currently, Zhang tells the Journal that "it doesn't seem convincing."