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First editing of human embryos reportedly carried out in United States

Germline editing aims to pass on genetic modifications to future generations - This content is subject to copyright.
Germline editing aims to pass on genetic modifications to future generations - This content is subject to copyright.

The first successful attempt to remove inherited disease by genetically modifying human embryos has reportedly taken place in the US.

Researchers at Oregon Health and Science University (OHSR) are understood to have altered the genetic composition of large numbers of single-cell embryos using an editing technique that replaces faulty genes.

Previous Chinese attempts at CRISPR editing have been only partially successful and led to accusations of “wild west” eugenics.

The technology to support research into correcting diseases is readily available

Dr Helen O’Neill, UCL

If confirmed in a forthcoming peer-reviewed journal, the new research would constitute the first attempt at American gene-editing, a field which has so far been held back by fears of “designer babies”.

Shoukhrat Mitalipov, who led the study, declined to confirm the results ahead of their formal publication, however scientists on his team told MIT Technology Review they showed it was possible to safely and efficiently correct defective genes causing inherited disease.

The embryos were allowed to develop only for a few days before being destroyed and there was never an intention to implant them into a womb.

The reported experiment may nevertheless mark a milestone on a journey towards genetically modified humans.

In the last two years, scientific opinion in the US has grown more sympathetic to germline editing, where a genetically modified child can pass on changes to future generations.

Francis Crick Institute - Credit: Bloomberg
London's Francis Crick Institute is also researching gene editing Credit: Bloomberg

In 2015, bioethicists at the National Academy of Scientists (NAS) said it would be “irresponsible” to use gene editing technology in human embryos for therapeutic purposes until safety issues were resolved.

But earlier this year, NAS and the National Academy of Medicine said scientific advances had made the procedure a “realistic possibility that deserves serious consideration”.

Research, such as that reported at OHSR is legal in the US providing it is not backed by Federal funds.

In the UK, the Francis Crick Institute has been granted permission to genetically modify human embryos, but for the purposes of investigating the death of babies in the womb rather than editing out inherited disease.

In the Chinese studies, the desired DNA changes were not taken up by the whole embryo, an effect called mosaicism.

A scientist familiar with the new Oregon research said it was “Proof of principle that it can work.

“They significantly reduced mosaicism,” he said

“I don’t think it’s the start of clinical trials yet, but it does take it further than anyone has before,”

Dr Helen O’Neill, Programme Director of Reproductive Science and Women’s Health, Embryology, IVF and Reproductive Genetics Group at University College, London, said: “Unfortunately, the news about the potential ability to correct disease has been eclipsed by the fear of so-called “designer babies”.

“The technology to support research into correcting diseases is readily available and is largely limited only by legislative barriers.”