These findings imply that while the underlying cause of axonal deficiencies observed in SMA remains unclear, induction of autophagy and subsequent accumulation of autophagosomes may be a major contributing factor; a hypothesis supported by the finding that inhibition of Beclin 1, a regulator of autophagy required for induction, significantly delayed neuronal degeneration (Garcera et al., 2013). This evidence concerns the gene BECN1 and proximal spinal muscular atrophy.