ACYs amyloidosis ICD-10: E85.4+ I68.0*; ICD-11: 8B22.3

Cerebral amyloid angiopathy (ACys/CAA) is a rare cerebrovascular disease characterized by the accumulation of amyloid beta peptide in the leptomeninges and small/medium cerebral blood vessels. The amyloid deposits lead to fragile vessels that may manifest in lobar intracerebral hemorrhage. This systemic amyloidosis may also present with cognitive impairment, incidental microbleeds, hemosiderosis, inflammatory leukoencephalopathy, Alzheimer's disease, or transient neurologic symptoms.

ACys amyloidosis can be hereditary but also sporadic.

It is caused by mutations in the CST3 gene (20p11.2), which encodes cystatin C.

Onset of symptoms at 20-30 years of age, with systemic amyloidosis and recurrent lobar intracerebral hemorrhages (Cerebral Amyloid Angiopathy, Cst3-Related).

The diagnosis is made primarily by a combination of clinical, pathologic, and radiologic findings.

However, postmortem examination of the brain is required for a definitive diagnosis.

Currently, there are no disease-modifying treatments.

Prognosis depends on the characteristics of the CAA, with poorer outcomes in patients with large hematomas and older age.

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