Moyamoya syndrome in hemoglobin E-beta thalassemia: A rare presentation and association.

Moyamoya disease is an idiopathic, nonatherosclerotic, noninflammatory, chronic progressive cerebrovascular disease characterized by bilateral stenosis or occlusion of the arteries around the circle of Willis, typically the supraclinoid internal carotid arteries, followed by extensive collateralization, which are prone to thrombosis, aneurysm, and hemorrhage. Secondary moyamoya phenomenon or moyamoya syndrome (MMS) occurs in a wide range of clinical scenarios including prothrombotic states such as sickle cell anemia, but the association with other hemoglobinopathies is less frequently observed. We describe a case of a 25-year-old female with hemoglobin E-beta thalassemia who had a rare presentation of MMS in the form of choreoathetoid movements in the left upper and lower extremities. We describe this association, primarily to emphasize thalassemia as an extremely rare but a potential etiology of MMS. Since MMS is a progressive disease, it is important to diagnose and initiate treatment to prevent worsening of the disease and recurrence of stroke.