ITM2B and amyloidosis: This category includes mutations (such as the Dutch mutation) involving the amyloid-β coding domains of the amyloid precursor protein gene (APP), mutations primarily associated with familial AD (where CAA can also co-exist; copy number variants of APP, including duplications or triplications like trisomy 21, mutations of PSEN1 and PSEN2), and non-amyloid-β CAA mutations like mutations in the integral membrane protein 2B (ITM2B), cystatin C or gelsolin amyloidosis, and mutations in transthyretin [11,203,204,205,206,207,208].