Therefore, failures in the differentiation and migration of neural crest cells may lead to the insufficiency of anterior cerebral circulation, including MMD, multisystemic smooth muscle dysfunction syndrome caused by ACTA2 mutation, and PHACE syndrome, which are collectively named vascular neurocristopathy (cardio-cephalic neural crest syndrome) (Komiyama, 2017b). Here, ACTA2 is linked to multisystemic smooth muscle dysfunction syndrome.