• Clinical science

Hereditary spastic paraplegia

Summary

Hereditary spastic paraplegias (HSP) are a rare group of inherited neurodegenerative diseases which mainly affect the longest axons of the corticospinal tract and the dorsal column (which supply the lower limbs). HSP is caused by defects in genes which code for proteins essential for fast axonal neurotransmission. HSP can affect any age group. Patients present with upper motor neuron palsy of bilateral lower limbs, gait abnormalities, and urinary urgency/urge incontinence. Dorsal column dysfunction is usually mild. Additional neurological features such as epilepsy, peripheral neuropathy, or cerebellar signs may be present (complicated HSP). Diagnosis is mainly clinical. MRI of the spinal cord may demonstrate spinal cord atrophy. Treatment is mainly supportive, with skeletal muscle relaxants, botulinum toxin, and physiotherapy for muscle spasticity. HSP may be nonprogressive (childhood-onset) or progressive (adult-onset). Patients with progressive HSP are often wheelchair-bound by the age of 70 years. Patients with HSP have a normal life-expectancy.

Epidemiology

  • Incidence: < 10 per 100,000 general population
  • Age of onset: variable (from early childhood till the 8th decade of life)

References:[1][2][3]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

References:[2]

Pathophysiology

References:[2][4]

Clinical features

Pure HSP (Uncomplicated HSP)

Pure HSP is characterized by an insidious onset and slow progression of the following symptoms

Complicated HSP

Patients with complicated HSP have all the features of pure HSP as well as additional neurological features, such as:

References:[1][3][5][6][7][8]

Diagnostics

The diagnosis of HSP is based on a positive family history, characteristic clinical features, and the exclusion of other neurological conditions.

Lumbar puncture and CSF analysis are usually normal!

References:[2][5][9]

Treatment

References:[6][10][11]

Prognosis

  • Prognosis depends on the age of onset.
    • Early onset HSP (in childhood): may be nonprogressive; most patients remain ambulant
    • Late onset: progressive; most patients will require wheelchairs by age 70
  • Life-expectancy: normal

References:[3][5]