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Spastic paraplegia type 8
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Spastic paraplegia type 8

Spastic paraplegia type 8 is a rare, inherited neurological disorder characterized by progressive muscle stiffness and weakness in the legs.

Overview

Spastic paraplegia type 8 belongs to a group of disorders known as hereditary spastic paraplegias. It is classified as a pure (or uncomplicated) type, meaning it primarily involves the nerves and muscles that control the legs and bladder, rather than affecting the nervous system in other parts of the body.

Symptoms

Signs and symptoms typically begin in early to mid-adulthood, though they can start in childhood. Key features include:

  • Spasticity: Progressive muscle stiffness in the legs.
  • Muscle weakness: Often severe enough that affected individuals require wheelchair assistance in adulthood.
  • Hyperreflexia: Exaggerated reflexes.
  • Sensory and bladder issues: Decreased ability to feel vibrations and reduced bladder control.

Symptoms can vary significantly, even among members of the same family.

Causes

The condition is caused by variants in the WASHC5 gene, which provides instructions for making a protein called strumpellin. Strumpellin interacts with the cell's structural framework (the cytoskeleton) and helps regulate endosomes—structures responsible for sorting, transporting, and recycling cellular materials. Variants in this gene are thought to reduce functional strumpellin, likely impairing the transport of molecules within nerve cells.

Inheritance

Spastic paraplegia type 8 is inherited in an autosomal dominant pattern, meaning one copy of the altered gene in each cell is sufficient to cause the disorder. In approximately 90 percent of cases, the variant is inherited from an affected parent. The remaining cases result from a new (de novo) mutation occurring during the formation of reproductive cells or early embryonic development.

Frequently Asked Questions

Perform timed voiding every 2‑3 hours and limit bladder irritants (caffeine, alcohol). Pelvic floor muscle training under a continence nurse’s guidance can improve sphincter control. If urgency or retention persists, a urologist may prescribe anticholinergic medication or consider intermittent catheterization.
First‑line therapy includes oral antispasmodics such as baclofen or tizanidine, titrated to effect while monitoring for drowsiness. Physical therapy focusing on stretching, strength training, and gait training is essential. In refractory cases, intrathecal baclofen pumps or botulinum toxin injections into over‑active calf muscles can provide additional relief.
Diagnosis combines a detailed neurological exam (spasticity, hyperreflexia, gait disturbance) with MRI to rule out other spinal cord pathology, followed by genetic testing for pathogenic variants in the WASHC5 (strumpellin) gene. A targeted hereditary spastic paraplegia panel or whole‑exome sequencing is recommended.
Discuss pre‑implantation genetic testing (PGT‑M) with a reproductive specialist to select embryos without the pathogenic variant. Prenatal diagnostic options include chorionic villus sampling (10‑12 weeks) or amniocentesis (15‑18 weeks) with targeted sequencing of WASHC5. Genetic counseling should be part of the decision‑making process.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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