Transthyretin amyloidosis (ATTR) is a rare systemic disease characterized by the progressive deposition of misfolded TTR protein in the heart and peripheral nerves, leading to transthyretin amyloid polyneuropathy (ATTR-PN) and transthyretin amyloid cardiomyopathy (ATTR-CM).488,489 Several NADs have been approved for ATTR treatment, including ASOs, such as inotersen490,491 and eplontersen,492 as well as siRNAs, such as patisiran97 and vutrisiran.493 These therapies work by disrupting the relevant mRNA, thus inhibiting TTR synthesis. Here, TTR is linked to cutaneous mastocytosis.