The news, sent as an email to Nature last week, follows a report in the Russian magazine N+1 that Rebrikov intended to alter eggs procured from a deaf couple (see BioNews 1005). However, according this latest announcement, his primary goal is to use eggs from women without the deafness mutation to better understand complications arising from 'off-target' mutations cause by CRISPR/Cas9 technology and not to create genome-edited babies.
'I will definitely not transfer an edited embryo without the permission of the regulator', said Rebrikov, regarding approval for his experiments from the Ministry of Health of the Russian Federation.
In turn, the Russian Health Ministry stated that they fully supported the WHO stance against making changes to the human germline until a better understanding of the technology and its implications were in place. Despite this, the chairman of the Ministry's ethic committee, geneticist Sergie Kutsev, described Russia as being in a 'legislative vacuum' regarding embryo editing – meaning that scientists such as Rebrikov can take risks that they shouldn't.
According to Nature, Rebrikov plans to publish the results of his egg experiments soon, which also include testing CRISPR's ability to repair mutations in the gene linked to deafness, GJB2, in somatic cells of people with the mutation.
Mutations to GJB2 impair cells in the inner ear that regulate auditory signals – a condition that impacts around 10 newborns a year in Russia. Rebrikov is now in discussion with five couples where both partners have two mutated GJB2 genes, and says he wants to help couples such as these have children without impaired hearing.
Critics of Rebrikov have called into question the benefits of this aim – hearing loss is not a fatal condition, and GJB2 is also linked to other diseases that affect the skin and eyes, meaning that altering the gene could have unpredictable consequences.
'The project is recklessly opportunistic, clearly unethical and damages the credibility of a technology that is intended to help, not harm', said Professor Jennifer Doudna, a pioneer of the CRISPR tool based at the University of California, Berkeley.
Following the birth of gene-edited twins in China last year (see BioNews 977), the use of the CRISPR-Cas9 system in embryos has become the focus of on-going controversy in the global scientific community.
Professor Robin Lovell-Badge, at the Francis Crick Institute in London, emphasised that more time is needed to develop a clear framework: 'This is not a simple matter, and it is ridiculous to think that we can come up with global solutions to regulation in a very complex scientific and potentially clinical area in a few months.'
In the future, and if his experiments are approved, Rebrikov has stated his intent to re-focus his attention on editing the CCR5 gene, which is reported to contribute to HIV-resistance, but has refused to comment further on theoretical interpretations of his plans.
'I have to get some data published in a reputable journal first. I don't want to talk with nothing to show', he said to STAT news.