Infantile-onset ascending hereditary spastic paralysis (IAHSP) is rare neurodegenerative disease characterized by onset of spasticity to lower limbs within the second year of life and progression towards spastic tetraparesis. This disorder is associated with mutations at the Amyotrophic Lateral Sclerosis type 2 (ALS2) gene, which encodes for Alsin, a protein composed by 1657 amino acids organized in multiple domains. Several studies on transgenic mice have highlighted its crucial role in vesicular trafficking, neuronal development, and homeostasis by virtue of its ability to interact with two guanosine triphosphatases, Rac1 and Rab5. In particular, evidence suggest that Rac1 can bind Alsin central region, composed by two structured domains i.e.