Comi et al (2005):
Found altered fibronectin expression in fibroblasts taken from port wine stains and brain compared to normal tissue from same subjects
Fibronectin has effects on angiogenesis, vessel remodeling, and vessel innervation density
No known genetic abnormality, possibly a somatic mutation
Comi AM, Weisz CJ, Highet BH, Skolasky RL, Pardo CA, Hess EJ.Sturge-Weber syndrome: altered blood vessel fibronectin expression and morphology. J Child Neurol. 2005 Jul;20(7):572-7.