Overview
Infantile-onset ascending hereditary spastic paralysis (IAHSP) is an extremely rare genetic condition that affects the motor neurons — the nerve cells that control voluntary muscle movement. It is sometimes also called infantile-onset ascending hereditary spastic paraplegia. The disease begins in infancy, typically within the first two years of life, and causes progressive stiffness (spasticity) and weakness that starts in the legs and gradually moves upward to affect the arms and eventually the muscles involved in speaking and swallowing. Children with IAHSP usually develop normally at first but then begin to show difficulty with walking and movement. Over time, the stiffness and weakness spread to the upper body. The condition primarily affects the upper motor neurons, which are the nerve cells in the brain and spinal cord that send signals to the muscles. Unlike some related conditions, IAHSP does not typically affect thinking or intelligence. There is currently no cure for IAHSP. Treatment focuses on managing symptoms and maintaining quality of life. This includes physical therapy to preserve mobility and reduce stiffness, medications to manage spasticity, and assistive devices such as braces or wheelchairs as the disease progresses. Speech therapy and feeding support may become necessary as the condition advances. Because the disease is so rare, research is limited, but genetic understanding has improved with the identification of the responsible gene.
Also known as:
Key symptoms:
Progressive leg stiffness (spasticity)Difficulty walking or inability to walkWeakness that starts in the legs and moves upwardStiffness and weakness in the armsDifficulty speaking (dysarthria)Difficulty swallowing (dysphagia)Exaggerated reflexesAbnormal walking patternMuscle wasting over timeLoss of fine motor skills in the handsBreathing difficulties in advanced stagesInvoluntary muscle spasmsProgressive loss of mobility
Clinical phenotype terms (11)— hover any for plain English
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Infantile
Begins in infancy, roughly 1 month to 2 years old
Treatments
No FDA-approved treatments are currently listed for Infantile-onset ascending hereditary spastic paralysis.
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Rare Disease Specialist
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Infantile-onset ascending hereditary spastic paralysis.
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Questions for your doctor
Bring these to your next appointment
- Q1.How quickly is this disease likely to progress in my child's case?,What therapies and medications can help manage the spasticity?,Should we consider an intrathecal baclofen pump, and when would that be appropriate?,Are there any clinical trials or research studies we could participate in?,What signs should we watch for that would indicate the disease is affecting breathing or swallowing?,How can we best support my child's development and education?,Should other family members be tested for the ALS2 gene mutation?
Common questions about Infantile-onset ascending hereditary spastic paralysis
What is Infantile-onset ascending hereditary spastic paralysis?
Infantile-onset ascending hereditary spastic paralysis (IAHSP) is an extremely rare genetic condition that affects the motor neurons — the nerve cells that control voluntary muscle movement. It is sometimes also called infantile-onset ascending hereditary spastic paraplegia. The disease begins in infancy, typically within the first two years of life, and causes progressive stiffness (spasticity) and weakness that starts in the legs and gradually moves upward to affect the arms and eventually the muscles involved in speaking and swallowing. Children with IAHSP usually develop normally at first
How is Infantile-onset ascending hereditary spastic paralysis inherited?
Infantile-onset ascending hereditary spastic paralysis follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Infantile-onset ascending hereditary spastic paralysis typically begin?
Typical onset of Infantile-onset ascending hereditary spastic paralysis is infantile. Age of onset can vary across affected individuals.
Which specialists treat Infantile-onset ascending hereditary spastic paralysis?
20 specialists and care centers treating Infantile-onset ascending hereditary spastic paralysis are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.