Author Response: Safety of AADC Gene Therapy for Moderately Advanced Parkinson Disease: Three-Year Outcomes From the PD-1101 Trial

We appreciate the comment by Kang et al. on our research.1 While we acknowledge findings of toxicity in a mouse model of elevated cellular dopamine due to overexpression of the dopamine transporter,2 such toxicity has not been observed in rodent or primate models of Parkinson disease (PD) in which the aromatic L-amino acid decarboxylase (AADC) gene therapy was tested.3,4 Moreover, in our observations of these participants 3 years after AADC therapy,1 we did not see evidence of significant clinical worsening, which would be expected if the AADC gene therapy was causing injury to medium spiny neurons.