TTR and Familial transthyretin-related amyloidosis: There are two forms of transthyretin amyloidosis (ATTR), which result from amyloidogenic transthyretin (TTR) proteins: the wild-type ATTR (ATTRwt) amyloidosis, formerly known as senile systemic amyloidosis, with a dominant cardiac phenotype and associated with aging; and the hereditary ATTR amyloidosis, also known as ATTRv, caused by pathogenic variants in the TTR gene.