China's CRISPR twins raise possibility of far off-target effects

China’s CRISPR twins might have had their brains inadvertently enhanced

New research suggests that a controversial gene-editing experiment to make children resistant to HIV may also have enhanced their ability to learn and form memories.

The brains of two genetically edited girls born in China last year may have been changed in ways that enhance cognition and memory, scientists say.

The twins, called Lulu and Nana, reportedly had their genes modified before birthby a Chinese scientific team using the new editing tool CRISPR. The goal was to make the girls immune to infection by HIV, the virus that causes AIDS.

Now, new research shows that the same alteration introduced into the girls’ DNA, deletion of a gene called CCR5, not only makes mice smarter but also improves human brain recovery after stroke, and could be linked to greater success in school.