Hereditary Spastic Paraparesis

What is Hereditary Spastic Paraparesis?

Hereditary spastic paraparesis (HSP), also called hereditary spastic paraplegia, is a group of inherited neurodegenerative disorders that mainly cause progressive stiffness and weakness in both legs. It results from length-dependent degeneration of nerve pathways, especially the corticospinal tracts and, in some forms, dorsal column neurons. Symptoms can appear at any age, from infancy to late adulthood, depending on the genetic type. Estimates suggest a prevalence of 2 to 5 per 100,000 people worldwide. Early recognition helps guide supportive care, genetic counseling, and symptom management.

What causes Hereditary Spastic Paraparesis?

HSP is linked to changes in many different genes that affect vital cellular processes, such as axonal transport, mitochondrial function, endoplasmic reticulum function, and myelin maintenance. These genetic defects leave the long axons of the corticospinal tract vulnerable to damage. Autosomal dominant inheritance is common, especially in adult-onset cases, but autosomal recessive, X-linked, and mitochondrial forms also occur. These cellular problems mainly affect the longest nerve fibers, leading to gradual distal axonal loss. This damage eventually causes the slowly progressive gait changes seen in the condition.

What are the signs and symptoms of Hereditary Spastic Paraparesis?

The hallmark symptoms are progressive stiffness, spasticity, and weakness in the legs. Individuals often exhibit hyperreflexia (overactive reflexes) and extensor plantar responses during a neurological exam. Bladder urgency or incontinence and mild sensory changes in the feet may accompany the motor findings. In more complex presentations, additional features like ataxia, speech problems, peripheral neuropathy, seizures, optic nerve problems, or cognitive changes may be present. People may first notice subtle tripping or a stiff gait, with bladder symptoms developing later.

How is Hereditary Spastic Paraparesis diagnosed?

A thorough diagnosis starts with a detailed history and a focused neurological examination. Clinicians first need to exclude acquired mimics, such as multiple sclerosis, vitamin B12 or copper deficiency, infections, or mechanical spinal cord compression. MRI of the brain and spinal cord may be normal in pure HSP, but it helps rule out structural lesions; spinal cord atrophy or a thin corpus callosum may be seen in some forms. Nerve conduction studies and EMG can help determine whether peripheral nerve involvement is present. Genetic testing, often with a multigene panel and sometimes whole-exome sequencing, can confirm a molecular diagnosis when a pathogenic variant is found and can guide counseling and long-term planning.

How is Hereditary Spastic Paraparesis treated?

There is currently no cure or disease-modifying therapy for HSP. Current treatment strategies prioritize managing symptoms and maintaining an individual’s mobility. Physical therapy helps maintain the range of motion and prevents contractures. Medications such as baclofen or tizanidine may be used to reduce muscle stiffness, although the benefit varies. In refractory cases, an intrathecal baclofen pump may be considered for more direct symptom control. Orthotics and various mobility aids support a stable gait, while urologic follow-up may be needed to manage bladder dysfunction

What are the most important facts to know about Hereditary Spastic Paraparesis?

• This group of disorders involves progressive corticospinal tract loss that can manifest from childhood through late adulthood.
• Many HSP-related genes can impair axonal health, leading to characteristic stiffness, weakness, and gait difficulty.
• Core symptoms include lower limb spasticity, weakness, hyperreflexia, and bladder urgency or incontinence.
• A successful diagnosis requires ruling out acquired causes and using genetic testing when appropriate.
• There is no curative or disease-modifying treatment, so care focuses on physical therapy, medications for stiffness, bladder management, and mobility aids.