Hereditary spastic paraplegias (HSPs) are human genetic disorders causing increased stiffness and overactive muscle reflexes in the lower extremities. atlastin (ad) is one of the major genes in which mutations result in HSP. We generated a Drosophila model of HSP that has a null mutation in atl. As they aged, atl null flies were paralyzed by mechanical shock such as bumping or vortexing. Furthermore, the flies showed age-dependent degeneration of dopaminergic neurons. These phenotypes were rescued by targeted expression of atl in dopaminergic neurons or feeding L-DOPA or SK&F 38393, an agonist of dopamine receptor. Our data raised the possibility that one of the causes of HSP disease symptoms in human patients with all mutations is malfunction or degeneration of dopaminergic neurons. (C) 2006 Elsevier Inc. All rights reserved.