TTR and restrictive cardiomyopathy: In particular, TTR V122I is the most common variant responsible for ATTR-CM being almost exclusively found in 3–4% of African-Americans and, the predominant phenotype associated with this mutation is severe restrictive cardiomyopathy with late-onset, i.e., occurs mainly after the age of 60, without neurological symptoms (Jacobson et al., 1997; Quarta et al., 2015; Buxbaum and Ruberg, 2017).