Phenotypic characteristics and clinical management of Alagille syndrome with multiple intracranial aneurysms: a case report and literature review.

BACKGROUND: Alagille syndrome (ALGS) is an autosomal dominant multisystem developmental disorder associated with JAG1 and NOTCH2 mutations. Although vascular involvement is recognized, life-threatening intracranial hemorrhage as the initial presentation is extremely rare. CASE PRESENTATION: A 5-year-old male presented with a severe headache and was diagnosed with intracerebral and subarachnoid hemorrhage caused by multiple ruptured intracranial aneurysms. Genetic testing confirmed a pathogenic JAG1 mutation, establishing the diagnosis of ALGS. The patient, who had known aortic stenosis, developed infective endocarditis-raising the possibility that infection was driving the aneurysms. After two microsurgical craniotomies, he ultimately died of multi-organ failure. CONCLUSIONS: This case highlights a rare presentation of ALGS involving acute rupture of multiple intracranial aneurysms, complicated by cardiac malformation and infective endocarditis, with newly formed aneurysms highly suspected to be infection-driven. ALGS should be considered in young children presenting with early intracranial hemorrhage, particularly when cardiac anomalies coexist. Early multidisciplinary intervention may prevent the catastrophic sequelae of ALGS-associated intracranial aneurysms.