The MaesTTRo study aims to enroll a global cohort of patients with transthyretin (ATTR) amyloidosis to longitudinally observe the natural course of the disease and describe real-world treatment patterns and outcomes. In addition, information on the effectiveness of ATTR amyloidosis treatments, including eplontersen, which is a ligand-conjugated antisense oligonucleotide gene silencing treatment targeting activity against both the mutant and wild-type TTR protein, will be collected.