SMN2 and proximal spinal muscular atrophy: The antiapoptotic role of SMN (Anderton et al., 2013) and the activation of apoptotic processes through the PI3K-Akt neuronal survival pathway has been stablished in SMA (Sansa et al., 2021a) and has been associated with CAPN1 loss of function in cerebellar ataxia (Wang et al., 2016).