A researcher at the Broad Institute who is one of the pioneers of the CRISPR gene editing technique is talking, with the news that a scientist in China claims to have created the world's first genetically modified babies.
Feng Zhang is a biological engineer at the Broad Institute and professor of neuroscience at MIT. He is one of the developers of the CRISPR gene editing, and has great concerns about the use of the technique in human embryos at this time.
Jack Lepiarz of WBUR spoke with Zhang by phone from Hong Kong, where he attends the international summit on the human genome edition. The news of the apparent development of the gene edition broke just before the summit was launched. Chinese scientists, He Jiankui, will speak at the summit.
Jiankui says he used gene editing in embryos of twin girls to eliminate a gene that allows HIV to enter cells, which aims to prevent girls from becoming infected with the HIV virus.
The father of the twins is HIV positive, but according to reports, a different technique was used, which consists of washing the sperm to separate it from semen infected with HIV to prevent transmission of the virus to the embryos.
Zhang says that the editing of genes is still quite new, with technical challenges and ethical issues that still need to be addressed.
"From a technical perspective, it is known that the gene editing system is capable of performing unwanted editions, and these are called" misplaced objectives ", explains Zhang. "So, even if we are trying to fix Gen A, for a fraction of the time it is possible that they can be edited in locations B, C and D, and maybe even more, and because we do not know what is not wanted. changes – how they can affect the way the body works – there are very high risks of moving forward to use this in the embryo. "
Zhang says that causing a genetic alteration can have additional unintended consequences, for example, in this case, causing a greater chance of contracting West Nile virus or dying from the flu. And these genetic alterations will be carried from generation to generation, he says.
Highlights of the interview:
If the gene is eliminated, the person is much less likely to become infected with HIV, but it also makes them more likely to contract West Nile Virus or to suffer a fatality in the case of a flu infection. There are also other mutations. For example, in the gene called PCSK9, where in some people it reduces cholesterol, but sometimes it has also been shown that it can increase the risk of diabetes.
If the enzyme, in addition to doing what you want it to do, also modifies a gene related to cancer, then you may see an increased risk of a tumor. And so, because of these two types of unwanted side effects, the technology is not really ready to be implemented.
In the future, for a disease in which we know the real causal mutation, then I can imagine that people would want to enter the embryo and correct those mutations.
In the very short term, what we will see is that the technology will be developed for applications in somatic cells for the treatment of diseases. […] and not doing so in such a way that the changes pass to subsequent generations. And as we develop technology in this way, we will learn much more security, efficiency and also the best ways to apply technology. And that will require many years of work with technology to understand its limitations and strengths. At that time, we could be ready to apply it to embryos.