'Twin' familial aneurysms of the anterior communicating artery

Two sisters harbouring an intracranial aneurysm are described. Rather than merely adding new cases to the records of familial aneurysms, this communication reports clinical and radiological findings supporting the hypothesis of inheritance: same anatomical location with involvement of the anterior communicating artery (ACoA), which is uncommon when dealing with familial aneurysms, and similar morphology of the lesions; identical haemodynamic pattern; similar timing of haemorrhage, occurring in both cases during the sixth decade.