Despite the encouraging preclinical and clinical results of IV rAAV9 for SMA and other neurological diseases (60), a recent study failed to demonstrate the effectiveness of IV rAAV9 gene replacement therapy (1 × 1014 vg/kg) in an Ngly1–/– Sprague-Dawley rat model (43). The gene discussed is NGLY1; the disease is proximal spinal muscular atrophy.