SPAST and hereditary spastic paraplegia: Similar results were also obtained in other lines expressing different UAS-spastin RNAi (Supplementary Fig. 3A and B), according to different fly models carrying spastin mutations, and resembling human motor deficits observed in SPG4-HSP patients.17,34-36 Indeed, only a small percentage of spastin-RNAi flies reached the target point in the defined time.