hereditary cystatin c amyloid angiopathy hereditary cystatin c amyloid angiopathy hereditary cystatin c amyloid angiopathy (hccaa) is a rare, fatal amyloid disease in young people in iceland caused by a mutation in cystatin c. most of the families with the defect gene can be traced to a region in the northwest of iceland, around breiðafjörður. hereditary cystatin c amyloid angiopathyother nameshereditary cerebral hemorrhage with amyloidosiscystatin c(or cystatin 3) which is involved in this condition mutations in the cystatin 3 gene are responsible for the icelandic type of hereditary cerebral amyloid angiopathy, a condition predisposing to intracerebral haemorrhage, stroke and dementia. the condition is inherited in a dominant fashion.