Aneurysmal sub-arachnoid haemorrhage in patients with Noonan syndrome: a report of two cases and review of neurovascular presentations in this syndrome.

To date, intracranial aneurysms have been reported in two patients with Noonan syndrome. We report two unrelated patients with Noonan syndrome who presented with sub-arachnoid haemorrhage secondary to intracranial aneurysms. These cases are discussed and other cerebrovascular abnormalities that have been described in association with Noonan syndrome are reviewed. Ultrastructural and genetic factors contributing to these associations are considered.