Variability among patients in terms of age of disease onset also may depend on the phenotype.39 Traditionally, TTR-FAP and ATTRv-CM were considered two distinct disorders, although ATTR is now considered to be a single disease with a spectrum of manifestations, including nearly exclusively neuropathy or cardiomyopathy, or (more commonly) a combination of these and other manifestations. This evidence concerns the gene TTR and cutaneous mastocytosis.