TFG and hereditary spastic paraplegia: Independently of these findings, TFG was recently revealed to be a causal gene of several neurodegenerative diseases, including hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P)10, the axonal type of Charcot-Marie-Tooth disease (CMT2)11 and hereditary spastic paraplegia (HSP)12.