About Lulu and Nana: Twin Girls Born Healthy After Gene Surgery As Single-Cell Embryos

Two Chinese girls, who we’ll call Lulu and Nana to protect their privacy, were born healthy a few weeks ago. Their mother Grace started her pregnancy by regular IVF with one difference: right after sending her husband’s sperm into her eggs, an embryologist also sent in CRISPR/Cas9 protein and instructions to perform a gene surgery intended to protect the girls from future HIV infection. The surgery reproduces a natural genetic variation shared by more than 100 million people of primarily European origin that confers strong resistance to initial HIV-1 infection and disease progression. While CRISPR/Cas9 has been studied in human cells and in early clinical trials, gene surgery in embryos intended for pregnancy has not previously been reported. Safety remains a key concern, particularly for unintended changes to the genome. To assess the girls’ genomes for safety after the surgery, multiple whole genome and targeted deep sequencing techniques were used before implantation, during the pregnancy, and now after bi