The Alagille syndrome (AGS) or arteriohepatic dysplasia is a rare, autosomal dominant inherited disease with a prevalence of approximately 1:100,000. AGS was first described in 1969 and affects liver, heart, arterial blood vessels, skeleton and the eyes. The expression of AGS is variable. In severe cases a liver transplantation is required. Presented is the case of a 25-year-old woman with AGS. At the age of 7 and 8years she had liver transplantations. Other typical findings associated with Alagille syndrome (e.g. pulmonary or renal anomalies) were also present. The young woman apparently died suddenly and unexpectedly in a good health condition despite regular medical treatment. Cause of death was a subarachnoid hemorrhage with invasion of the hemorrhage into the ventricle system caused by a rupture of previously unknown large aneurysm in the terminal basilary artery. Intracranial vascular malformations are a common finding in patients with AGS and cause death in up to 16% of them.Life expectancy in AGS patients depends on the severity of changes of the affected liver. But AGS is also responsible for various vascular abnormalities in several other organs which can cause lethal complications. Due to the high rate of vascular complications and intracranial hemorrhage with the leading cause of mortality in patients with AGS, vascular screening by the use of noninvasive imaging techniques (CT or MR angiography) is required to avoid unexpected sudden death.