Moyamoya syndrome in a child with Down syndrome.

Moyamoya syndrome has rarely been reported in association with Down syndrome. We report a case of an 11-year-old female child with Down syndrome who presented with hemiparesis and facial palsy. Imaging investigations (magnetic resonance angiography and digital subtraction angiography) revealed the classical Moyamoya pattern. Work-up for prothrombotic and autoimmune disorders was negative. The neurological deficits recovered well. The association of Moyamoya syndrome in patients with Down syndrome has been highlighted. The possible causes for the association and management have been reviewed briefly.