Mass General Brigham Sep 11 2025 Multisystemic smooth muscle dysfunction syndrome (MSMDS) is a rare condition associated with stroke, aortic dissection (tearing) and death in childhood. Currently, there is no effective treatment or cure for MSMDS. A single error in the genetic code of the ACTA2 gene, which encodes the smooth muscle actin protein, is the most common cause of MSMDS. To directly target this mutation, researchers from Mass General Brigham engineered a bespoke CRISPR-Cas9 gene-