TTR and cardiomyopathy: One of these structurally characterized proteins, prealbumin (a.k.a. transthyretin, PDB ID: 2pab (12)), was subsequently validated as the target of tafamidis, a small-molecule drug (molecular weight or MW < 1000 Da) approved by the United States (US) Food and Drug Administration (FDA) in 2019 for treatment of adults diagnosed with cardiomyopathy due to transthyretin-mediated amyloidosis.