Cystatin C

Cystatin 3, usually called Cystatin C (also CST3 and Gamma trace) is a serum protein used mainly as a measure of glomerular filtration rate. It is a single 120-residue polypeptide belonging to the type 2 cystatin gene family. Studies have shown that Cystatin C allows a more precise testing of kidney function than creatinine.

Mutations in the cystatin 3 gene are responsible for the Icelandic type of hereditary cerebral amyloid angiopathy, a condition predisposing to intracerebral haemorrhage.