In 2010, the disorder known as CADASIL syndrome is one of the most common causes of hereditary vascular dementia. However, the mechanisms involved in this disease of the small cerebral vessels remain poorly understood. This is because of the absence of a good animal model on which they can be studied. Recently, a FrancoGerman collaboration has been able to remedy this shortfall by obtaining a transgenic mouse model which develops the same lesions as those relating to CADASIL syndrome. Anne Joutel and her team at Inserm Unit 740, "Genetics of the vascular diseases", have recently published their work in the Journal of Clinical Investigation on 1st February 2010.