What is cystatin C amyloidosis (ACys)?

Updated: May 09, 2019
  • Author: Robert O Holmes, Jr, DO; Chief Editor: Herbert S Diamond, MD  more...
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The precursor protein in cystatin C amyloidosis (ACys) is cystatin C, which is a cysteine protease inhibitor that contains a point mutation. This condition is clinically termed HCHWA, Icelandic type.

ACys is autosomal dominant. Clinical presentation includes multiple strokes and mental status changes beginning in the second or third decade of life. Many of the patients die by age 40 years. This disease is documented in a 7-generation pedigree in northwest Iceland. The pathogenesis is one of mutant cystatin that is widely distributed in tissues, but fibrils form only in the cerebral vessels; therefore, local conditions must play a role in fibril formation.

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