SMN1 and proximal spinal muscular atrophy: SmnRes/Res;SMN2;SMNΔ7 mice were used as non-induced SMA mice (herein referred to as ‘SMA’) and Smn+/−;SMN2;SMNΔ7;Cre-ER+/− or Smn+/+;SMN2;SMNΔ7;Cre-ER+/− were used as non-SMA controls (herein referred to as ‘Control’).