A Multicenter Observational Study to Evaluate the Effectiveness of Patisiran in Patients With Polyneuropathy of ATTRv Amyloidosis With a V122I or T60A Mutation

Inclusion Criteria: * Diagnosed with ATTRv amyloidosis with polyneuropathy, with a documented V122I or T60A mutation * PND score of I-IIIB at baseline. * Exposure to commercial patisiran in one of the 3 cohorts: * Prospective Cohort: Naive to patisiran treatment at the time of enrollment with intention to initiate treatment with patisiran. * Mixed cohort: Currently on commercial patisiran therapy for less than 12 months at study enrollment. * Retrospective cohort: Exposed to commercial patisiran treatment for at least 12 months prior to study enrollment, regardless of current treatment status at enrollment. Exclusion Criteria: * New York Heart Association (NYHA) heart failure classification ≥3 * Karnofsky Performance Status (KPS) \<60% * Unstable congestive heart failure (CHF) * Known primary amyloidosis (AL) or leptomeningeal amyloidosis * Prior major organ transplant * Previously received patisiran * Previous treatment with a TTR silencing therapy