Hereditary spastic paraplegia (HSP) (MIM#182600) is a group of heterogeneous neurodegenerative disorders, with 35 underlying loci recognized by the HGNC (HUGO Gene Nomenclature Committee;http://www.gene.ucl.ac.uk/nomenclature/) and 10 identified genes ( http://www.gene.ucl.ac.uk/cgi-bin/nomenclature/searchgenes.pl plus NIPA1, last search July 2006). The mode of inheritance may be autosomal dominant,autosomal recessive or X-linked. Among these, autosomal dominant spastic paraplegia (AD-HSP) is the most common type, accounting for 70%-80% of all families.1The disease is characterized by lower limb spasticity,hyperreflexia, progressive spastic gait and an extensor plantar response. Pes cavus is one of the commonly reported foot phenotypes.2