The interesting part to me: For the treatment, doctors remove stem cells from the patients' bone marrow and use CRISPR to edit a gene in the cells, activating

The interesting part to me: For the treatment, doctors remove stem cells from the patients' bone marrow and use CRISPR to edit a gene in the cells, activating the production of fetal hemoglobin. That protein is produced by fetuses in the womb but usually shuts off shortly after birth. The patients then undergo a grueling round of chemotherapy to destroy most of their bone marrow to make room for the gene-edited cells, billions of which are then infused into their bodies. This means that it wasn't in vivo modification, which would be truly revolutionary for many genetic diseases. Still, it's spectacular progress that will help millions eventually.