Furthermore, AD-HSP is thought to be a neurodegenerative disease that progresses over a period of years, and it is unclear whether neurodegeneration as a result of spastin mutations could occur during the short lifespan of Drosophila. Further work will be required to determine to what extent the Drosophila system can provide an organismal model for AD-HSP pathology. The gene discussed is SPAST; the disease is hereditary spastic paraplegia.