A case of hypoplasia of internal carotid artery and intracranial vasculopathy with Moyamoya syndrome in association with Alagille syndrome.

Alagille syndrome (ALGS), also known as arteriohepatic dysplasia, is a rare multisystem vascular disorder affecting brain, liver, heart, ophthalmic and skeletal systems. Moyamoya syndrome is a rare arteriopathy due to an underlying cause that can lead to ischemic and hemorrhagic strokes. Here, we report a rare case of ALGS in a patient with congenital narrowing of bilateral internal carotid arteries (ICA) with superimposed intracranial arteriopathy and associated moyamoya syndrome. A 34-year-old female presented with progressively worsening intermittent right eye visual blurriness, associated headache, and dizziness. Digital subtraction angiogram findings were consistent with the bilateral intracranial steno-occlusive disease at the ICA terminus with moyamoya collaterals at the skull base; bilateral posterior communicating arteries supplied the bilateral middle cerebral arteries, and the left ophthalmic artery supplied the distal right anterior cerebral artery. Her right-sided vision abnormalities were highly concerning for branch retinal artery occlusion based on fundoscopic exam. She continued antiplatelet therapy and was scheduled for an ophthalmology follow-up as an outpatient. The patient was monitored in outpatient stroke clinic with surveillance scans. Due to patient preference and the absence of further strokes on preventive medications, the initial plan of external carotid artery to ICA bypass was deferred. Early identification of moyamoya syndrome and initiation of secondary stroke preventive therapy in symptomatic patients can reduce the incidence of ischemic strokes. This is an important consideration for patients transitioning from pediatric to adult neurologists, as the latter may not be as familiar with managing this condition.