Abstract

Clinical and histological accounts are given of a sister and brother, dying aged 61 and 56 years respectively after illnesses lasting 5-6 years marked by a progressive mental and physical disability. The family history suggested transmission by a dominant gene. The histological findings were of a very severe congophilic angiopathy confined to the brain, spinal cord and leptomeninges and giving rise to multiple haemorrhages and softenings. There were, in addition, abundant amyloid-containing "plaques" of various forms, found principally in the hippocampus and cerebellar cortex. The cases are compared with similar cases in the literature, and reasons given for regarding this condition as a separate entity rather than a variant of Alzheimer's disease.