Dementia with non-hereditary cystatin C angiopathy.

Brain biopsies from two patients with non-hereditary cerebral hemorrhages and eighty autopsied cases with the clinical diagnosis of dementia are presented. The biopsied cases, both males aged 64 and 59, had a sudden onset of cerebral hemorrhage, mild progressive dementia and cystatin C cerebral amyloid angiopathy. Of the autopsied cases 59 had senile plaques and cerebral amyloid angiopathy was also found in 36 of them. Both senile plaques and the blood vessel amyloid stained positively with beta-protein antibodies, and five of them also showed a positive reaction to cystatin C antibodies. These cystatin C positive cases were three males aged 76, 80 and 83, and one female 93 years old and the fifth case was a female aged 47 with Down's syndrome.