Sneddon's syndrome.
A 24 year old woman presented with generalised livedo reticularis and progressive intellectual decline. A CT scan of her head showed multifocal low density areas, consistent with cerebral infarction. Cerebral angiography revealed occlusive disease of major vessels, an arteriovenous malformation, and moya-moya type anastomoses. There was no other associated systemic illness. Sneddon's syndrome was the provisional diagnosis. Her older brother had the same skin condition and was also shown to have occlusive cerebrovascular disease. The pathogenesis and natural history of this uncommon disease are highlighted.