**1. Introduction**

CADASIL (MIM 125310) is the acronym for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, coined in 1993 to define a hereditary small vessel disease of the brain affecting middle-aged adults and leading to disability and dementia [1, 2]. The disease was first described in 1955 by Van Bogaert as "Binswanger's disease with a rapid course in two sisters" [3]. Before 1993, a number of families with an apparently hereditary vascular dementia accompanied by a Binswanger-like arteriopathy were described [3–5], but only in 1991, Tournier-Lasserve et al. [6] described nine patients of a single family, with

recurrent cerebrovascular ischemic events and dementia, variably associated with migraine headaches and epilepsy, suggesting the term "autosomal dominant syndrome with stroke-like episodes and leukoencephalopathy." In 1993, a linkage analysis of two unrelated European families led to the mapping of the defective gene to chromosome 19q12, and the syndrome was renamed CADASIL [1]. Compared with other inherited brain disorders such as Huntington's disease or inherited early-onset Alzheimer's dementia, CADASIL is still relatively unknown in the medical community. This is not so much due to the fact that it is a rare disease but more to the fact that there is only a short history of recognition of the disease [7].
