CADASIL, artériopathie cérébrale et systémique autosomale dominante associée à des accidents ischémiques sous-corticaux et à une leucoencéphalopathie: une revue

CADASIL is an increasingly recognised inherited arterial disease involving brain vessels and, to a lesser degree, systemic vessels, with an autosomal dominant pattern of transmission. Affected individuals have migraine, mood disturbances, cognitive changes and recurrent strokes often progressing to subcortical dementia associated with pseudobulbar palsy, gait disturbances, and loss of sphincter control. The disease begins at the age of 40 to 50 and death eventually occurs usually 20 years after the first manifestation of the disease. Magnetic resonance imaging and pathological examination show multiple subcortical lacunar infarcts and diffuse leukoencephalopathy. Brain and leptomeningeal vessels and, to a lesser degree, systemic arterial vessels show nonamyloid, nonarteriosclerotic changes characterised by a hyaline thickening and deposition of a granular eosinophilic material in the media. Cardiovascular risk factors, particularly hypertension, are usually missing. At the ultrastructural level, the most consistent finding consists of a deposition of a granulated osmiophilic material in the extracellular matrix and a destruction of vascular smooth muscle cells. The presence of this material in small arteries of a skin biopsy allows to confirm the suspicion of CADASIL in presence of suggestive clinical and brain imaging features and of similar clinical symptoms in first relatives. The disease has been reported in several families and shown to be caused by strongly stereotyped mutations of the Notch3 gene on chromosome 19q12. However, occurrence of CADASIL due to de novo noninherited mutation of Notch3 gene has also been reported. Recent investigations have shown that the expression of the nonmutated Notch3 is restricted to vascular smooth muscle cells in adult human tissues. In CADASIL, a cleavage product of mutated Notch3 dramatically accumulates at the cytoplasmic membrane of smooth muscle cells near the granular osmiophilic deposits.