Brief Communication Unique Cerebrovascular Anomalies in Noonan Syndrome With RAF1 Mutation

Noonan syndrome is a common autosomal dominant neurodevelopmental disorder caused by gain-of-function germline muta-tions affecting components of the Ras-MAPK pathway. The authors present the case of a 6-year-old male with Noonan syndrome, Chiari malformation type I, shunted benign external hydrocephalus in infancy, and unique cerebrovascular changes. A de novo het-erozygous change in the RAF1 gene was identified. The patient underwent brain magnetic resonance imaging, computed tomo-graphy angiography, and magnetic resonance angiography to further clarify the nature of his abnormal brain vasculature. The authors compared his findings to the few cases of Noonan syndrome reported with cerebrovascular pathology