TTR and amyloidosis: Amyloidosis is a group of diseases in which abnormal protein aggregates, known as amyloid fibrils, build up in the brains of patients with Alzheimer's disease (AD), as well as in various organs in cases of amyloid light-chain (AL) amyloidosis, transthyretin (ATTR) amyloidosis, and mouse apolipoprotein A-II (AApoAII) amyloidosis [1–3].