TTR and amyloidosis: Transthyretin (TTR), previously called prealbumin, is mainly produced by the liver in a tetrameric circulating protein form and transports thyroid hormones and vitamin A. There are two types of ATTR amyloidosis: (i) variant transthyretin-related amyloidosis (ATTRv)—a familial disorder arising from the misfolding of a variant transthyretin; and (ii) wild-type transthyretin amyloidosis (ATTRwt)—a sporadic disorder due to the misfolding of wild-type transthyretin [3].