NTRK1 and amyotrophic lateral sclerosis: The up-regulation of Ngfr and Erbb3, which encode the high-affinity neurotrophin receptor TRKA and the neuregulin-associated tyrosine kinase receptor, respectively, could be involved in Schwann cell paracrine functions (Wang et al., 1996; Lyons et al., 2005; Adilakshmi et al., 2011) as well as in early, complex mechanisms of axonal retraction and neuromuscular junction alterations in ALS prior to motor neuron degeneration (Kerkhoff et al., 1991; Gorlewicz et al., 2009).