Background and purpose: Moyamoya disease is a very rare occlusive cerebrovascular disorder characterized by progressive stenosis or occlusion of the intracranial portion of the internal carotid artery and proximal cerebral arteries with an extensive network of fine collaterals. The aetiology and genetic susceptibility of moyamoya disease, especially in Caucasians, still remains unclear. Methods and results: We describe the cases of affected German father, daughter and son with juvenile stroke because of idiopathic moyamoya disease. The rare existing literature is reviewed and discussed. Conclusions: This is the first report on a father-to-child inheritance pattern in Caucasian patients with idiopathic Moyamoya disease (MMD). Our cases indicate possible genetic risk factors for the genesis of Caucasian Moyamoya disease.