Hereditary cystatin C amyloid angiopathy is an autosomal dominant disorder in which a variant form of cystatin C (L68Q) readily forms amyloid deposits in cerebral arteries in affected individuals resulting in early death.
The resulting intracellular accumulation and increased localised concentration of L68Q cystatin C might be an important event in the molecular pathophysiology of amyloid formation and brain haemorrhage in patients with HCCAA.
Clones overexpressing the two variants showed increased secreted levels of cystatin C. Within the cells the L68Q variant appeared to mainly localise to the endoplasmic reticulum rather than to acidic vesicular organelles, indicating limitations in the transport out from the cell rather than increased uptake as explanation for the elevated cellular cystatin levels seen in 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, which is an inhibitor of several cysteine proteinases, such as cathepsins S, B, and K. The same mutation in cystatin C, L68Q, has been found in all patients examined so far pointing to a common founder.
One of rather atypical, occurring at a young age amyloidosis is hereditary cystatin C amyloid angiopathy (HCCAA) related to aggregation of L68Q variant of human cystatin C (hCC).
In order to test this hypothesis, we used matrix-assisted laser desorption ionization time-of-flight mass spectrometry in an effort to demonstrate the presence of L68Q- along with wildtype cystatin C in plasma and cerebrospinal fluid (CSF) of HCCAA-patients.
The state of denaturation of L68Q cystatin C in vivo is thus a critical factor for the concentration of active cysteine proteinase inhibitor in cerebrospinal fluid and likely also for the development of amyloidosis, in HCCAA patients.
Recent studies have reported a genetic association between the 73 G/A polymorphism within exon 1 of the cystatin C gene and Alzheimer's disease (AD) with conflicting results.
Here, we strengthen the evidence that an nsSNP (p.Ala25Thr) in the cysteine proteinase inhibitor cystatin C gene CST3, previously confirmed by meta-analysis to be associated with AD, is associated with exudative AMD.
The state of denaturation of L68Q cystatin C in vivo is thus a critical factor for the concentration of active cysteine proteinase inhibitor in cerebrospinal fluid and likely also for the development of amyloidosis, in HCCAA patients.
Increased body temperature accelerates aggregation of the Leu-68-->Gln mutant cystatin C, the amyloid-forming protein in hereditary cystatin C amyloid angiopathy.
One of rather atypical, occurring at a young age amyloidosis is hereditary cystatin C amyloid angiopathy (HCCAA) related to aggregation of L68Q variant of human cystatin C (hCC).
We have generated lines of transgenic mice expressing either wild-type human cystatin C or the Leu68Gln variant that forms amyloid deposits in the cerebral vessels of Icelandic patients with hereditary cerebral hemorrhage, under control sequences of the human cystatin C gene.
Cystatin C Leu68Gln variant is known to induce amyloid deposition in cerebral arterioles, resulting in Icelandic type cerebral amyloid angiopathy (CAA).
Here, we strengthen the evidence that an nsSNP (p.Ala25Thr) in the cysteine proteinase inhibitor cystatin C gene CST3, previously confirmed by meta-analysis to be associated with AD, is associated with exudative AMD.
Targeting of cystatin C to the Golgi apparatus and processing through the secretory pathway of RPE cells are dependent upon a 26-amino acid signal sequence of precursor cystatin C. A variant with an alanine (A) to threonine (T) mutation in the penultimate amino acid of the signal sequence (A25T) was recently correlated with increased risk of developing exudative age-related macular degeneration.