Introduction: Strokes are common but can be caused by a rare illness. Moyamoya disease (MMD) justifies a family assessment because of its hereditary nature and the availability of new therapies.
Case description: A 42-year-old man was admitted because of convulsions with sensorimotor deficit due to a massive cerebral haemorrhage caused by MMD. The fact that the patient died suggested his children should be screened.
Discussion: MMD is rare and its consequences disastrous. Many cases in both children and adults have been described. Investigations should be carried out when the diagnosis is suspected, and, if confirmed, the family should be screened given the genetic nature of some forms of the disease. Effective and increasingly personalized therapeutic solutions are available.
Conclusions: A minority of strokes are caused by rare diseases including MMD. Our current knowledge of this pathology and the treatments available justify a family assessment when the clinical or family context requires it.