Hereditary Spastic Paraplegia (HSP), also called Familial Spastic Paraplegias or Strumpell-Lorrain disease, is a group of inherited diseases whose main feature is progressive stiffness and contraction (spasticity) in the lower limbs, as a result of damage to dysfunction of the nerves. It sometimes also affects the optic nerve and retina of the eye, causes cataracts, ataxia (lack of muscle coordination), epilepsy, cognitive impairment, peripheral neuropathy, and deafness. HSP is caused by defects in the mechanisms that transport proteins and other substances through the cell. Long nerves are affected because they have to transport cellular material through long distances, and are particularly sensitive to defects of cellular transport.

Die Spastische Spinalparalyse, auch Hereditäre Spastische Spinalparalyse (HSP/FSP), ist eine genetisch bedingte neurodegenerative Erkrankung, ausgehend vom ersten motorischen Neuron.

Le terme de paraplégie spastique familiale regroupe un ensemble de maladies génétiques génétiquement hétérogènes qui se caractérise par :
Faiblesse musculaire très progressive atteignant les membres inférieurs s’accompagnant d’une hypertonie musculaire entraînant une raideur du membre inférieur.