Alagille Syndrome and Aneurysmal Subarachnoid Hemorrhage

The authors report the case of a 21-year-old female with a known history of Alagille syndrome (AGS) who was found to have a basilar terminus aneurysm without evidence of rupture. Prior to intervention, the patient's hospital course became complicated by multiple medical problems associated with AGS. Subsequently, the patient had an acute neurological decline. An unenhanced CT of the head demonstrated diffuse subarachnoid hemorrhage, intraparenchymal hematoma and intraventricular hemorrhage. AGS is an autosomal dominant arteriodysplastic syndrome with multiple organ system involvement caused by a mutation in the Jagged1 gene. Intracranial hemorrhage is one of the many complications observed in this patient population. While there are multiple case reports in the literature reviewing the spectrum of cerebrovascular events and abnormalities, intracranial aneurysmal rupture has only recently been described. To our knowledge, this is the third reported case of documented aneurysmal subarachnoid hemorrhage in a patient with AGS. The authors present a brief review of the vascular abnormalities both intracranial and systemic seen in AGS. The genomic abnormalities of this syndrome are also reviewed with particular attention to the Jagged1 gene and the Notch receptor signaling pathway which may reveal elements of the pathophysiology involved in aneurysm formation and rupture in AGS patients. In light of the increased incidence of intracranial hemorrhage in AGS and the possible link to aneurysmal subarachnoid hemorrhage, establishing the incidence of intracranial aneurysms in AGS and the role of screening these patients is indicated.