The two GMO babies born in China following He Jiankui’s experiments have a risk of early mortality; so concludes a study published on Monday in the journal Nature Medicine . Last November, when the Chinese scientist announced that he had produced genetically modified twin girls, he believed that he had made them resistant to the AIDS virus. But “genetics works like a Mikado game, in which moving a single small stick can cause many others to move”.
The Chinese researcher used the CRISPR-Cas9 tool, genetic scissors that enable genome parts to be modified or replaced “just like a typing error is corrected on a computer”. He thereby created a modification on the CCR5 gene, the AIDS virus receptor. This genetic modification is naturally present in 1% of Europeans and “prevents the virus from entering host cells, making carriers resistant to AIDS”.
In the study published on Monday, the researchers compiled statistics on a population of 400,000 volunteers registered in the UK Biobank register. Their results reveal that carriers of two copies of the mutated gene have “a significantly higher mortality rate between the ages of 41 and 78 than people with only one copy or none”. They also show that the Chinese twins will have a 20% lower chance of reaching the age of 76. In addition, this alteration appears to “reduce protection against other infectious diseases such as influenza”.
The study’s two authors – Xinzhu Wei, from the University of California at Berkeley in the United States, and Rasmus Nielsen from the University of Copenhagen – conclude that “introducing mutations into humans via genetic engineering techniques is a considerable risk, even though these mutations seem to offer an advantage”. They also state that “witchcraft apprentices who would like to improve humans […] may achieve the opposite effect”. For Professor Graham Cooke of Imperial College London, this study “does highlight the need to understand mutations in greater detail before we consider creating them medically”.
For further reading: