SMN1 and proximal spinal muscular atrophy: Indeed, the zinc finger protein ZPR1 interacts with SMN protein and exerts a pro-survival effect on MNs: ZPR1 is important for the accumulation of SMN in the nucleus; SMA patients express lower levels of ZPR1 and the inhibition of the Zpr1 gene in SMA mutant mice increases the severity of the pathology, with higher caspase-mediated neuron degeneration [127].