We have developed a new mouse model of transthyretin (TTR) amyloidosis using transgenic mice expressing the most fibrillogenic variant of TTR (S52P). Following seeding with amyloid fibrils, TTR amyloid is deposited mainly in the heart and tongue. The fibrils contain both full length and truncated (49-127) TTR. The presence of S52P TTR was confirmed by proteomics. Knockout of alpha2-antiplasmin enhanced amyloid deposition.