Transthyretin amyloidosis (ATTR) has been recognized as an underdiagnosed and undertreated cause of cardiomyopathy, as well as noncardiac disorders including polyneuropathy, spinal stenosis, and carpal tunnel syndrome. 1 The evolution of the non-biopsy diagnosis of transthyretin cardiac amyloidosis (ATTR-CA) along with new and emerging therapies has escalated the recognition of this multisystem disorder. 2,3 Once considered rare, recent studies have shown prevalence of ATTR-CA in up to 13% of patients hospitalized with heart failure and preserved ejection fraction 4 ; 16% of patients with aortic stenosis undergoing transcatheter valve replacement 4 ; 7-8% of patients undergoing carpal tunnel release surgery 5 ; and 25% of persons >80 years on an autopsy series. 6 With the increase in recognition and diagnosis of ATTR-CA, the development of targeted treatments has evolved and grown rapidly over the past decade.Amyloidoses are a group of protein misfolding disorders where misfolded proteins form insoluble amyloid fibrils that deposit in the tissues leading to organ damage and dysfunction. Two types of amyloid account for 95% of cardiac amyloidosis: light-chain amyloid (AL) due to immunoglobin light-chain deposition and transthyretin cardiac amyloidosis (ATTR) which can be due to hereditary mutation (hATTR) or wildtype transthyretin (wtATTR). 1 Transthyretin (TTR), previously known as prealbumin, is a 55,000-Dalton protein that is synthesized primarily in the liver, and serves as a serum transport protein for thyroxine and retinol, hence deriving the name transthyretin for TRANSporter of THYroxine and RETINol. Although TTR is the primary serum transport protein for retinol-binding protein, it is only a minor transport protein for thyroxine in plasma, with <1% of TTR thyroxine bound due to a