Scientists have successfully performed ‘chemical surgery’ on the genetic code of an embryo, ridding it of an inherited blood disease.
The DNA alteration, made possible for the first time ever by the CRISPR editing tool, was undertaken by a team of researchers in China who told the BBC about their results.
Junjiu Huang, one of the researchers, said: “We are the first to demonstrate the feasibility of curing genetic disease in human embryos by base editor system.”
With the aim of one day being able to treat a range of inherited diseases before birth, the team at Sun Yat-sen University, focused on the root cause of many of these problems - single point mutations to one building block in our DNA.
People living with the disease beta-thalassemia, that the NHS says can cause anything from severe anemia, shortness of breath, to heart palpitations, have a single point mutation in an A base.
One single A base was wrongly expressed as a G, so the team in China simply edited the G back to an A, using CRISPR, correcting the problem.
What is CRISPR?
CRISPR stands for ‘Clustered Regularly Interspaced Short Palindromic Repeats’ and in the field of genome engineering is loosely used to refer to various tools that can be programmed to target specific stretches of genetic code at precise locations.
CRISPR was first discovered by Francisco Mojica, at the University of Alicante, Spain, and in 2013 the Zhang Lab published the first method to engineer CRISPR to edit the genome in mouse and human cells.
But in order to do this, it required scanning the three billion building blocks that make up the human genome.
The team used lab-made embryos, that had been cloned from tissues taken from a patient with the pre-existing condition, but were not implanted.
The experiment was stopped as work of this kind with modified embryos is not permitted to carry children to term.
It is only for purposes of “better understanding” human development, even in China were rules are more relaxed than elsewhere in the world.
In the UK where, the UK Human Fertilisation and Embryology Authority (HFEA) 2016 licensing, states that embryos must be destroyed within 14 days and cannot be implanted into a woman after being altered.
Previous trials in China, that looked at deleting a deadly heart condition, resulted in “mosaic” cells that are a tapestry of healthy and unhealthy cells, as well as parts of the genetic code being mutated.