DDC and proximal spinal muscular atrophy: To date, rAAV-based biologics have been successfully marketed: Upstaza [5], for aromatic L-amino acid decarboxylase (AADC) deficiency; Roctavian [6], for hemophilia A patients; Luxturna [7], for inherited retinal disease (IRD); Zolgensma [8], for spinal muscular atrophy (SMA); and Hemgenix (EtranaDez) [9], for hemophilia B. Beyond North America and Europe, where these drugs are commonly marketed, rAAV-based therapies are becoming increasingly popular in research, and several are currently undergoing clinical trials in China [10,11].