Massive deposition of the variant cystatin C in the cerebral vessels of patients with the Icelandic form of hereditary cerebral hemorrhage with amyloidosis is thought to be responsible for the pathological processes leading to stroke.
However, the secreted variant cystatin C exhibited an increased susceptibility to a serine protease in conditioned media and in human cerebrospinal fluid, explaining its depletion from the cerebrospinal fluid of HCHWA-I patients.
We report a case of sporadic CAA with ICH in an elderly Croatian man with a mutation in cystatin C identical to that found in Icelandic hereditary cerebral hemorrhage with amyloidosis.
Based on the recent discovery of co-localization of beta/A4 and cystatin C in cortical blood vessels of patients with cerebral hemorrhages due to sporadic amyloid angiopathy and patients with Alzheimer's disease we investigated the presence of these two proteins in the cortical blood vessels of patients suffering from hereditary cerebral hemorrhage with amyloidosis of the Dutch (n = 11) and the Icelandic (n = 2) type.
To understand the molecular basis of the genetic defect, the gene encoding cystatin C was isolated from genomic DNA libraries made from normal tissue and the brain of an Icelandic patient with hereditary cerebral hemorrhage with amyloidosis (HCHWA-I).
This investigation demonstrates that hereditary cerebral hemorrhage with amyloidosis may be diagnosed by two laboratory methods: immunohistochemical investigation of cystatin C in brain tissue specimens and quantitation of cystatin C in cerebrospinal fluid.
Hereditary cerebral amyloid angiopathy: the amyloid fibrils contain a protein which is a variant of cystatin C, an inhibitor of lysosomal cysteine proteases.
Amyloid fibril in hereditary cerebral hemorrhage with amyloidosis (HCHWA) is related to the gastroentero-pancreatic neuroendocrine protein, gamma trace.