Blood vessels within the brain supply oxygen but also allow circulation of other molecules, ions, and cells between the blood and the brain. About one in 200 people form cerebral cavernous malformations (CCMs), which are irregular collections of small cerebral vessels that alter the flow of blood and can result in headaches, seizure, hemorrhage, paralysis, or stroke. Li et al. used the zebrafish model system and CRISPR-Cas9 mutagenesis to inactivate the CCM gene. As a result, the caudal venous plexus became dilated, “honeycombing” of the vein lumen disrupted blood flow, and multiple blood-filled chambers with a risk of hemorrhaging formed.
eLife 10.7554/eLife.62155 (2021).