Furthermore, the ubiquitous distribution of plasmin, its structural similarities to trypsin [22], and the reported activation of plasminogen activation system (PAS) in other amyloid-related disorders, such as Alzheimer’s disease [23] and immunoglobulin light chain (AL) amyloidosis [24,25,26] indicate that this protease could have a key role in TTR amyloidogenesis. Here, PLG is linked to Alzheimer disease.