More than one study has examined the modifying effect of theZPR1gene on SMA patients, and most of these studies were conducted by Gangwani et al. In their study on mice, Gangwani et al reported that the deficiency of the ZPR1 protein synthesized by theZPR1gene caused neurodegeneration.28 Here, ZPR1 is linked to proximal spinal muscular atrophy.