Transthyretin amyloid cardiomyopathy (ATTR-CM) is caused by the progressive accumulation of insoluble transthyretin amyloid fibrils in the myocardial extracellular space.1 It is thought to result from age-related failure of homeostatic mechanisms in wild-type ATTR-CM (nonhereditary form) or destabilizing mutations in variant ATTR-CM (hereditary form).1 Here, TTR is linked to cutaneous mastocytosis.