SMN1 and proximal spinal muscular atrophy: Another example of a life‐threatening neurodegenerative disease amenable to IUGT is SMA, caused by mutation or deletion of the survival motor neuron 1 gene (SMN1) on chromosome 5q13, resulting in the depletion of the ubiquitous SMN protein required for multiple fundamental cellular homeostatic and bioenergetic pathways.106