This report describes general characteristics of the group of diseases classified as spastic paraplegia (SPG) or hereditary spastic paraplegia (HSP). Spastic paraplegia is a genetically heterogeneous disorder with many causative genes and mapped loci. A comprehensive list of SPG subtypes, as defined by OMIM (which number over 70 to date), can be found by following the link in the "OMIM phenotypic series" section, below. A subset of these may be found in the table below, with links to more detailed reports for subtypes that have been investigated using fly models.
[updated Mar. 2020 by FlyBase; FBrf0222196]
The hereditary spastic paraplegias (SPG, HSP) are a large group of clinically and genetically diverse disorders characterized by progressive, usually severe, lower extremity spasticity and weakness. SPG is classified by mode of inheritance (autosomal dominant, autosomal recessive, and X-linked) and whether the primary symptoms occur in isolation ('uncomplicated SPG') or with other neurologic abnormalities ('complicated SPG'). [from OMIM:182600; 15.06.29]
The major neuropathologic feature of autosomal dominant, uncomplicated SPG is axonal degeneration that is maximal in the terminal portions of the longest descending and ascending tracts (corticospinal tracts to the legs and fasciculus gracilis, respectively). [from OMIM:182600; 15.06.29]