The first approved siRNA-based therapeutic, Onpattro® (patisiran), is used to treat hereditary transthyretin amyloidosis (hATTR), a disease characterized by mutations in the gene encoding transthyretin and abnormal deposits (amyloids) of transthyretin protein, causing polyneuropathy and cardiomyopathy [30]. The gene discussed is TTR; the disease is Familial transthyretin-related amyloidosis.