Similar to what was reported for ALS models, early abnormalities in the sensory, mostly proprioceptive circuit, play a key role in determining altered MN excitability, up to MN loss, and motor system defects in SMA models (Jablonka et al. 2006; Ling et al. 2010; Mentis et al. 2011; Imlach et al. 2012; Lalancette-Hebert et al. 2016; Fletcher et al. 2017; Limanaqi et al. 2017). Here, SMN1 is linked to amyotrophic lateral sclerosis.