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Neurological & Neuromuscular

Angelman Syndrome (AS) Clinical Trials and Treatments

Also called Happy Puppet Syndrome, AS, Angelmans Syndrome

Angelman Syndrome results from the loss of function of the UBE3A gene, inherited through the maternal chromosome. This gene normally produces a protein important for regulating other proteins in nerve cells.

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About Angelman Syndrome

Angelman Syndrome results from the loss of function of the UBE3A gene, inherited through the maternal chromosome. This gene normally produces a protein important for regulating other proteins in nerve cells. When the maternal copy is missing or not functioning properly, the distinctive symptoms emerge. Developmental delay becomes apparent in the second half of the first year of life, with most children achieving limited or no meaningful speech. Physical characteristics may include a wide mouth, pointed chin, and fair skin and hair. The seizure disorder typically appears in the second or third year of life and can be quite resistant to treatment.

Children with Angelman Syndrome often have a characteristic happy appearance with frequent smiling and laughter that can seem inappropriate to the situation. Despite their intellectual disabilities, many children develop meaningful connections with caregivers and family members. Life expectancy is generally normal or near-normal, though seizure management requires ongoing attention. Management is multidisciplinary, involving pediatric neurologists, therapists, and developmental specialists.

Common Symptoms of Angelman Syndrome

Recognizing the signs of Angelman Syndrome early can lead to faster diagnosis and better outcomes. Symptoms may vary in severity from person to person. If you or a loved one are experiencing any of the following, consider speaking with a specialist.

  • Severe developmental delay and intellectual disability
  • Little or no speech, with limited communication abilities
  • Ataxia (unsteady gait and jerky movements)
  • Seizures, typically beginning between 2 and 3 years of age
  • Frequent smiling, laughing, and happy demeanor
  • Attention deficit and hyperactivity

Who Angelman Syndrome Affects

Angelman Syndrome typically manifests in infancy and early childhood, usually diagnosed between 6 months and 3 years of age. It affects males and females equally and occurs across all ethnic and racial groups. Most cases are caused by spontaneous genetic mutations, though some families have a hereditary pattern.

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Help Paying for Angelman Syndrome Treatment

Charity funds and drugmaker programs for Angelman Syndrome, checked at the source. Pick your insurance to see what fits.

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No charity fund for this condition is open right now. Funds reopen when they receive new donations; the foundations let you sign up to be told when one opens.

Status as each foundation showed it on September 28, 2026.

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Side Effect Explorer

Real-world side effect reports from the FDA Adverse Event Reporting System (FAERS). Includes both FDA-approved drugs and investigational therapies from active clinical trials. Click any drug to see what patients reported.

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Genetic Testing

Genetic testing can confirm a diagnosis, guide treatment decisions, and identify family members who may be at risk.

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Trusted Angelman Syndrome Resources

Reputable organizations and medical references for learning more about Angelman Syndrome, including disease registries, foundation resources, and clinical guidelines.

Active Clinical Trials for Angelman Syndrome

Use this Angelman Syndrome clinical trial finder to see the 10 studies recruiting patients in the United States and worldwide, with eligibility criteria in plain English. These studies play a critical role in advancing care for neurological & neuromuscular conditions and may offer access to treatments not yet widely available. Each trial below is sourced directly from ClinicalTrials.gov, with eligibility criteria translated into plain English to help patients and caregivers evaluate whether a study may be a fit.

TrialsSite mapPipeline timeline

Note: Trial recruitment statuses on ClinicalTrials.gov may not immediately reflect recent FDA decisions, sponsor announcements, or enrollment changes. Always confirm a trial's current status directly with the study coordinator before making plans.

10 active trials worldwide
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RECRUITINGPHASE3Recently updatedNCT07782827

CHAMPION: A Study to Evaluate the Efficacy and Safety of Obudanersen (ION582) in Children and Adults With Angelman Syndrome (AS)

Intervention: obudanersen

Sponsor: Ionis Pharmaceuticals, Inc.

The primary purpose of the study is to evaluate efficacy of obudanersen in participants with AS due to uniparental disomy or imprinting defects (UPD/ID) as measured through expressive communication.

Ages 2 Years – 50 Years1 location
Started Sep 2026Updated yesterdayEst. May 2028 (~1y 8m)
RECRUITINGPHASE3Recently updatedNCT07605429

BEACON - Phase III Clinical Study of Rugonersen in Angelman Syndrome.

Intervention: rugonersen, Sham procedure

Sponsor: OHB Pediatrics Ltd. · Medpace, Inc.

Purpose of the study is to evaluate the efficacy and safety of intrathecally administered rugonersen in pediatric and adult participants with Angelman syndrome.

Ages 1 Year – 50 Years3 locations
Started Jun 2026Updated 2 weeks agoEst. Mar 2029 (~2y 6m)
RECRUITINGRecently updatedNCT05293184

The Global Angelman Syndrome Registry

Intervention: Observational study only

Sponsor: Foundation for Angelman Syndrome Therapeutics, Australia

The Global Angelman Syndrome Registry is an online patient organisation driven registry to collect information about the natural history of children and adults with Angelman Syndrome. The registry will facilitate 1) recruitment for clinical trials into therapies and interventions...

Ages not specified1 location
Started Sep 2016Updated 3 weeks agoEst. Dec 2099 (~73y 3m)
RECRUITINGRecently updatedNCT07417137

A Natural History Study of Angelman Syndrome

Sponsor: Massachusetts General Hospital · Astellas Pharma Global Development, Inc.

The goal of this observational study is to learn about the natural progression of Angelman syndrome (AS) in children and adults with a confirmed genetic diagnosis of AS. The main questions it aims to answer are:

Ages 1 Year+1 location
Started Aug 2026Updated 1 month agoEst. Sep 2028 (~2 years)
RECRUITINGPHASE1, PHASE2Recently updatedNCT07181837

A Phase 1/2 Study of the Safety and Efficacy of MVX-220 in Angelman Syndrome

Intervention: MVX-220

Sponsor: MavriX Bio, LLC

The purpose of this study is to evaluate the safety and efficacy of MVX-220 gene therapy in children and adults with Angelman syndrome with UBE3A gene deletion, uniparental disomy, or imprinting center defect genotypes.

Ages 4 Years – 50 Years3 locations
Started Oct 2025Updated 2 months agoEst. Mar 2028 (~1y 6m)
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Active trial locations10 cities in the US
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Trial Pipeline

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Data from ClinicalTrials.gov, U.S. National Library of Medicine.
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Patient Communities

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Related Neurological & Neuromuscular Conditions

Other rare diseases in the neurological & neuromuscular category. Patients with Angelman Syndrome may find relevant research, shared treatment pathways, or overlapping clinical trials among these related conditions.

Angelman Syndrome News and Analysis

Trial Friend articles about Angelman Syndrome, newest first

Companies Developing Angelman Syndrome Treatments

5 pharmaceutical companies have Angelman Syndrome in their rare disease portfolio

Frequently Asked Questions About Angelman Syndrome