TTR and amyloidosis: TTR amyloidosis is a multisystemic life-threatening disease caused by a mutation in the gene encoding TTR, causing deposits of amyloid in peripheral nerves, the heart, kidney, and other organs.6 In a phase 3 trial using RNAi to inhibit mRNA expression of a mutated TTR gene, multiple clinical manifestations were improved.7 The APOLLO phase 3 trial showed an increase in the quality of life of patients with TTR amyloidosis.8 Patisiran reduced left ventricular wall thickness and longitudinal strain as well as levels of brain natriuretic peptide (a marker of impaired cardiac function).