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Disease Profile

Infantile-onset ascending hereditary spastic paralysis

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

<1 / 1 000 000

US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

IAHSP; Spastic paralysis, infantile onset ascending


Congenital and Genetic Diseases; Nervous System Diseases


Infantile-onset ascending hereditary spastic paralysis (IAHSP) is a neurological disorder characterized by progressive (worsening) weakness and stiffness of muscles in the arms, legs, and face. Initial symptoms usually occur within the first 2 years of life and include weakness of the legs, leg muscles that are abnormally tight and stiff, and eventual paralysis of the legs. Over time, muscle weakness and stiffness travels up (ascends) the body from the legs to the head. IAHSP is caused by mutations in the ALS2 gene and is inherited in an autosomal recessive pattern.[1][2] Although there is no specific treatment or cure, there may be ways to manage the symptoms, including physical and occupational therapy.[2] A team of doctors is often needed to figure out the treatment options for each person.


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Abnormal pyramidal sign
Loss of articulate speech
Difficulty articulating speech
Increased reflexes
Impaired mastication
Chewing difficulties
Chewing difficulty
Difficulty chewing

[ more ]

Spastic paraplegia
Spastic tetraplegia
Paralysis of all four limbs
30%-79% of people have these symptoms
Abnormality of eye movement
Abnormal eye movement
Abnormal eye movements
Eye movement abnormalities
Eye movement issue

[ more ]

Pseudobulbar behavioral symptoms
Percent of people who have these symptoms is not available through HPO
Abnormal lower motor neuron morphology
Abnormality of the eye
Abnormal eye
Achilles tendon contracture
Shortening of the achilles tendon
Tight achilles tendon

[ more ]

Autosomal recessive inheritance
Babinski sign
Poor swallowing
Swallowing difficulties
Swallowing difficulty

[ more ]

Infantile onset
Onset in first year of life
Onset in infancy

[ more ]

Morphological abnormality of the corticospinal tract
Motor delay
Muscle weakness
Muscular weakness
Pes cavus
High-arched foot
Worsens with time
Slow progression
Signs and symptoms worsen slowly with time
Slow saccadic eye movements
Slow eye movements
Urinary incontinence
Loss of bladder control


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

      • Genetics Home Reference (GHR) contains information on Infantile-onset ascending hereditary spastic paralysis. This website is maintained by the National Library of Medicine.

        In-Depth Information

        • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Infantile-onset ascending hereditary spastic paralysis. Click on the link to view a sample search on this topic.


          1. Infantile-onset ascending hereditary spastic paralysis. Genetics Home Reference Website. April 2016; https://ghr.nlm.nih.gov/condition/infantile-onset-ascending-hereditary-spastic-paralysis. Accessed 12/8/2016.
          2. Pr Enrico BERTINI. Infantile-onset ascending hereditary spastic paralysis. Orphanet. February 2014; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=293168. Accessed 12/8/2016.