TTR and cardiac amyloidosis: Main types of cardiac amyloidosis include monoclonal immunoglobulin light chain (AL) and transthyretin amyloidosis cardiomyopathy (ATTR-CM), of which ATTR-CM can be subtyped by pathogenic mutations in the transthyretin gene (ATTRm) or by the accumulation of amyloid fibrils composed of wild-type transthyretin protein (ATTRwt) [2–4].