Chapter 18 Hereditary Spastic Paraparesis

Abstract

Publisher Summary Hereditary spastic paraparesis (HSP) is a relatively uncommon hereditary neurodegenerative disease with an incidence reported between 1 in 10,000 and 1 in 100,000. The main feature is a progressive lower limb spasticity resulting from the degeneration of the corticospinal tracts within the spinal cord. The cause of the axonal degeneration in HSP is unknown. HSP is most commonly inherited in an autosomal dominant (AD) fashion. Autosomal recessive (AR) and X-linked recessive inheritance are also seen but much less frequently. HSP may be classified with respect to phenotype, age at onset, or genetic linkage/gene mutated. The HSP phenotype may be pure in which the spastic paraparesis occurs in isolation or complicated in which the spastic paraparesis is merely one component of a much more diverse phenotype. Genetically HSP can be classified to one of 19 genetic loci, and because genes have been identified at 8 of these loci, more precise genotype–phenotype correlations are becoming possible. In pure HSP, progressive spastic paraparesis is the prominent feature. Epilepsy has increasingly been described as complicating HSP.