A paper published in Nature by CRISPR innovator David Liu and a giant in medical genetics, Francis Collins, raises great hopes for treating a rare, devastating pediatric disease causing premature-aging (Hutchinson-Gilford progeria syndrome). “The outcome is incredible,” according to gene-therapy researcher Guangping Gao. “Dance on the lab bench” amazing, according to editing pioneer Fyodor Urnov. Let’s be clear: the CRISPR variant called a base-editor has helped only progeria mice so far, but results are beyond anyone’s wildest expectations. One injection is enough to fix the single-letter mutation in several tissues, doubling mice’s lifespan. To learn more, see David Liu’s tweets and the NIH Director’s Blog.