New research suggests that the life expectancy of the first people who were gene-edited – a pair of baby twin girls – would have been shortened because of the way their genes were modified.
The world was shocked by the genetic alterations of the twins by Prof He Jiankui in his efforts to give them some form of defense against HIV.
But compared to those mutations that happen normally in people and those that were being attempted to be created by Jiankui essentially made the twins more vulnerable to die young, claimed a study published in Nature Medicine.
He’s actions were “very dangerous” and “foolish”, say experts.
A gene called CCR5 was being targeted by Prof He. That is essentially a set of genetic instructions which play an important role in dictating the manner of functioning of the human immune system.
However, that gene is also the pathway that allows entry of the human immunodeficiency virus (HIV) into the body and which infect cells. That entry is essentially locked for HIV by the mutations to CCR5 and thereby making those mutated immune to HIV.
The procedure used by Prof He was to make embryos in an IVF clinic and then he altered t he CCR5 gene with the help of gene-editing technologies. The resulting girls – known as Lulu and Nana – were born last year.
New research claims that the role of the CCR5 in the human body is far greater than only creating vulnerability for HIV. Researchers say that the gene is active in the brain and has a role in combating other infections, particularly flu.
Nearly 410,000 people in the UK were included in the study that was conducted by and at the University of California, Berkeley. The study concluded that there was a 20 per cent more likelihood of people who had only the mutated version of CCR5 dying before they turned 78.
“In this case, it is probably not a mutation that most people would want to have,” said Prof Rasmus Nielsen, from UC Berkeley. “You are actually, on average, worse off having it.”
The gene-editing technology, known as Crispr, was still too risky to be using on children, said fellow researcher Dr Xinzhu Wei. “The Crispr technology is far too dangerous to use right now for germ-line editing,” she said.
The researchers however could not clearly draw out the implications for Lulu and Nana.
“It is impossible to predict if the mutations carried by the twin girls will have any effect,” said Prof Robin Lovell-Badge, from the Francis Crick Institute. This is because not all of the study subjects who carried the mutations died at an early age but were more likely to.
A complex relation between the DNA one is born with and the world ones lives in determines the life expectancy.
The way the CCR5 genes were muted by Prof He was similar instead of being identical to those humans possessing have HIV resistance which further complicated things.
The study “shows once more that He Jiankui was foolish to choose CCR5 to mutate,” Prof Lovell-Badge said.
(Adapted from BBC.com)