Recent advances in gene editing have delivered promising preclinical results in treating rare genetic disorders such as multisystemic smooth muscle dysfunction syndrome (MSMDS). Researchers at Massachusetts General Hospital engineered bespoke CRISPR-Cas9 base editors to precisely correct pathogenic ACTA2 mutations in mice, improving survival and vascular disease phenotypes. Meanwhile, Capsida Biotherapeutics paused its phase I/II trial for STXBP1 encephalopathy following a patient's death, underscoring both the promise and challenges of gene therapies for neurodevelopmental conditions. These developments emphasize the rigorous safety requirements and therapeutic potential of precision genome editing in pediatrics.