FYN and proximal spinal muscular atrophy: GSK-3β, FYN, and DYRK1A represent three closely related PKs widely investigated within the neurokinome context due to their pivotal roles in both the onset and development of complex CNS-related diseases, including neurodegenerative (e.g., AD, Pick’s disease (PiD), frontotemporal lobar degeneration (FTLD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS)) and neuromuscular disorders (e.g., spinal muscular atrophy (SMA) and myotonic dystrophy type 1 (DM1)) [19,20,21,22,23,24,25,26].