The constructs were then packaged into AAV9 and injected intravenously into SMNΔ7 mice, which is a severe SMA mouse model that harbors a single targeted null mutation (SMN–/–) and two transgenic alleles (hSMN2+/+and SMNΔ7+/+), recapitulating many of the clinical features observed in SMA type 1, such as motor neuron loss, motor function deficits, and early death. This evidence concerns the gene SMN2 and spinal muscular atrophy, type 1.