SMN1 and proximal spinal muscular atrophy: Recent research has unveiled the extensive impact of SMN depletion beyond motor neurons, implicating additional tissues such as the liver and pancreas in both SMA patients and mouse models of SMA (Bowerman et al., 2014; Bowerman et al., 2012a; Bowerman et al., 2012b; Deguise et al., 2019a).