Mammalian models for HSP show that Spastin deficiencies led to the generation of axonal swellings in neurons, which inhibit axonal MT-dependent transport of organelles such as mitochondria and APP-positive vesicles (Tarrade et al., 2006; Kasher et al., 2009; Denton et al., 2014). The gene discussed is SPAST; the disease is hereditary spastic paraplegia.