This four-year-old girl with Schimke immuno-osseous dysplasia (SIOD), caused by a loss of function mutation of the SMARCAL1 gene, presented with acute left hemiparesis. Her brain magnetic resonance imaging (MRI) revealed an acute ischemic infarction in the right hemisphere and narrowing of both internal carotid arteries (Fig 1A-C). She exhibited many features of SIOD: growth retardation ....