Hereditary Spastic Paraparesis
Related Subjects:
|Peripheral neuropathy
|Proximal myopathy
|Foot Drop
|Friedreich's Ataxia
|HTLV-1 Associated myelopathy (Tropical Spastic Paraparesis)
|Hereditary Spastic Paraparesis
🧠 About
- Hereditary Spastic Paraparesis (HSP), also called familial spastic paraplegia
- It is a group of inherited disorders causing progressive spastic weakness in the legs 🦵.
- Genetically heterogeneous – many different mutations can lead to a similar phenotype 🧬.
- Hallmark = slowly progressive spasticity + weakness of lower limbs, often with gait disturbance 🚶♂️.
🧬 Aetiology
- Genetics: Mutations found on chromosomes X, 2, 3, 8, 11, 12, 14, 15, 19.
- Most cases = autosomal dominant (AD), but AR and X-linked recessive (XLR) forms also exist.
- The commonest gene = SPAST (encodes spastin, important for microtubule stability and axonal transport).
- Pathology: defective microtubules → impaired axonal transport, especially in long corticospinal tract neurons ⚡.
🩺 Clinical Presentation
- Gradually worsening weakness + stiffness in legs.
- Scissor gait 🚶 due to hip adductor spasticity.
- Stiff, awkward gait with increased tone.
- Brisk reflexes, extensor plantar responses, exaggerated abdominal reflexes.
- No cerebellar signs (helps distinguish from ataxias).
🔎 Investigations
- Family history: Often diagnostic clue 👨👩👧.
- MRI spine: Usually normal – helps exclude cord compression or other structural myelopathies.
- EMG: Typically normal, since HSP affects central motor pathways, not peripheral nerves.
🧾 Differential Diagnosis
- Cord compression: Spasticity + weakness but usually with sensory loss/pain 🚨.
- Vitamin B12 deficiency: Subacute combined degeneration – look for sensory changes and anaemia 🩸.
- Infective myelopathy: e.g., HTLV-1 associated myelopathy / tropical spastic paraparesis 🌍.
💊 Management
- Spasticity control: Baclofen, Tizanidine, or targeted Botulinum toxin injections 🎯.
- Physiotherapy: Maintain mobility, prevent contractures, gait training 🏃.
- Genetic counselling: Essential for affected families 🧬.
- Although progressive and incurable, symptom control + supportive care greatly improves quality of life 💙.
Cases - Hereditary Spastic Paraparesis (HSP)
- Case 1 - Pure HSP in a Young Adult 👣:
A 22-year-old man reports gradually worsening leg stiffness and difficulty walking over 5 years. Exam: bilateral spastic paraparesis, brisk knee reflexes, ankle clonus, extensor plantar responses. No sensory loss. Family history: father with similar gait.
Diagnosis: Pure hereditary spastic paraparesis (autosomal dominant).
Management: Physiotherapy, baclofen for spasticity, genetic counselling.
- Case 2 - Complicated HSP with Neuropathy 🧠:
A 30-year-old woman develops progressive leg stiffness and weakness since her teens. Exam: spastic gait, brisk reflexes, distal wasting, mild glove-and-stocking sensory loss. MRI spine: normal.
Diagnosis: Complicated HSP with associated peripheral neuropathy.
Management: Supportive - physiotherapy, orthotics, neuropathic pain medication, MDT care.
- Case 3 - Childhood-Onset with Cognitive Features 🧬:
A 12-year-old boy presents with delayed walking, increasing leg stiffness, and learning difficulties. Exam: spastic paraparesis, scoliosis, mild dysarthria. Strong family history in siblings.
Diagnosis: Complicated HSP (childhood onset, cognitive involvement).
Management: Supportive neurorehabilitation, spasticity control (baclofen, botulinum toxin), special educational needs support, genetic testing for family.
Teaching Commentary 🧠
Hereditary spastic paraparesis (HSP) = group of genetic disorders causing progressive spasticity and weakness of the legs due to corticospinal tract degeneration.
- Pure HSP: only lower limb spastic paraparesis ± bladder symptoms.
- Complicated HSP: additional features (neuropathy, ataxia, seizures, cognitive impairment, optic atrophy).
Inheritance: autosomal dominant most common; recessive and X-linked forms exist.
Diagnosis: clinical + family history, genetic testing (SPG mutations), exclusion of mimics (MS, structural cord lesions, HTLV-1 myelopathy).
Management: no disease-modifying therapy - focus on spasticity control, physiotherapy, orthotics, and genetic counselling. Life expectancy usually normal.
