Recruiting

Observational Study

Sponsor:

Massachusetts General Hospital

Code:

NCT07417137

Conditions

Angelman Syndrome

Neurodevelopmental Conditions

Eligibility Criteria

Sex: All

Age: 1+

Healthy Volunteers: Not accepted

Study Details

Brief summary:

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:

  • How do developmental skills, such as communication, motor abilities, and adaptive behaviors, change over a 1-year period in people with AS?
  • Are there specific patterns in brain activity or sleep that are associated with changes in AS symptoms over time?

Participants will:

  • Attend 3 in-person and 2 virtual study visits over 1 year for assessments.
  • Complete tests and questionnaires about development, behaviors, and sleep with the help of their caregivers.
  • Undergo electroencephalograms (EEGs) to measure brain activity and wear a sleep-monitoring device at home (to collect actigraphy data).

Conditions

Angelman Syndrome

Neurodevelopmental Conditions

Study ID

NCT07417137

Start date

Aug, 2026

Status verified date

Aug, 2026

Completion date

Sep, 2029

Anticipated

Primary completion date

Sep, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 1+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • The participant has a primary clinical diagnosis of Angelman syndrome with documented genetic variation(s) affecting the function of the UBE3A gene within the human 15q11.2-q13.3 locus. Co-occurring conditions (e.g., autism spectrum disorder, cerebral palsy, intellectual disability) are permitted; however, Angelman syndrome must be the primary clinical diagnosis.
  • The participant is male or female (assigned sex at birth) and aged ≥1 year at the initial study visit.
  • The participant has a study partner who meets the study partner criteria below.
  • The participant, if unable to provide informed consent, has an appropriate surrogate who is at least 18 years of age and willing and able to provide informed consent on behalf of the participant in accordance with current International Council for Harmonisation (ICH) guidelines and applicable institutional regulations.

Individuals must satisfy the following criteria to be enrolled as study partners:

  • The study partner is a parent or primary caregiver who is at least 18 years of age.
  • The study partner has consistent contact with the participant and, in the opinion of the investigator, is sufficiently knowledgeable about the participant's ongoing condition to provide accurate and current information.
  • The study partner has sufficient English-language proficiency to complete study partner assessments.
  • The study partner is willing and able to provide informed consent on their own behalf in accordance with ICH guidelines and applicable institutional regulations.
  • The study partner is, in the opinion of the investigator, reliable and competent; willing and able to accompany the participant to all study visits and comply with study procedures; reachable by telephone or email as needed; and sufficiently knowledgeable about the participant's ongoing condition(s) to provide accurate and current information regarding the participant's health and well-being.

Exclusion Criteria:

  • The participant has at least one additional known genetic abnormality outside the human 15q11.2-q13.3 locus causing a probable or known developmental disability.
  • At least one standard-of-care treatment (medication or adjunctive therapy) used by the participant was changed during the 28 days (4 weeks) prior to the first study visit. Treatments include, but are not limited to, doses of anti-epileptic medications, behavioral management medications, sleep medications, gabapentin, cannabidiol, special diets, supplements, speech therapy, occupational therapy, applied behavioral analysis (ABA), psychosocial interventions, physical therapy, or nutritional support.
  • The participant has unstable epilepsy, defined as having an emergency department visit or hospitalization for seizure-related concerns within the 28 days (4 weeks) preceding the initial study visit.
  • The participant is of childbearing potential and is either pregnant, breastfeeding, or not using an adequate method of contraception; abstinence is acceptable.
  • The participant has a clinically relevant history of malignancy; clinically significant abnormal test results; clinically significant cardiovascular, hematologic, hepatic, muscular, neurologic, or renal disease; or has experienced other clinical events which, in the opinion of the investigator, render participation unsuitable.
  • The participant has a lifetime history of treatment with any cell- or gene-based therapy, including antisense oligonucleotides or gene-editing therapies.
  • The participant has received any investigational therapy other than a cell- or gene-based therapy within 28 days or 5 half-lives (whichever is longer) preceding the initial study visit.
  • The participant is currently enrolled or plans to enroll in an interventional study involving an investigational agent or device during the planned observation period.
  • The participant has a known contraindication to electroencephalography, actigraphy, or any other study procedure described in the schedule of assessments.
  • The participant or study partner is, in the opinion of the investigator, unsuitable for participation in any other way, including an inability to fulfill study requirements.

Study Design

Enrollment

40 participants

Anticipated

Interventions and Outcome Measures

Arms

Participants aged 1-17 years (inclusive)

  • Cohort 1: Participants aged at least 1 year old and less than 18 years old at the time of enrollment with genetically confirmed AS.
  • This cohort serves as the broad group for assessing the natural history of AS across childhood and adolescence.

Participants aged 1-12 years (inclusive)

  • Cohort 2: Participants aged at least 1 year old and younger than 13 years old at the time of enrollment with genetically confirmed AS.
  • A subset of Cohort 1, specifically focused on preadolescents.
  • This cohort aims to capture developmental milestones and changes during a critical period of growth where potential therapeutic interventions may have the most significant impact.
  • Participants aged 1-12 years will first be assigned to Cohort 2 until its capacity is reached. Once Cohort 2 is full, participants aged 1-12 years will be enrolled in Cohort 1 only.

Participants aged 18 years and older

  • Cohort 3: Participants aged at least 18 years old.
  • This cohort is limited to up to 5 participants to explore the natural history of AS in adults, though it is not the primary focus of this study.

Primary outcome measure

  • Change from Baseline in Bayley Scale of Infant Development, Fourth Edition (Bayley-4) Cognitive Growth Score Equivalent at 12 Months [ Time Frame: Week 0, Week 26, Week 52 ]
  • Change from Baseline in Bayley Scale of Infant Development, Fourth Edition (Bayley-4) Receptive Communication Growth Score Equivalent at 12 Months [ Time Frame: Week 0, Week 26, Week 52 ]
  • Change from Baseline in Bayley Scale of Infant Development, Fourth Edition (Bayley-4) Expressive Communication Growth Score Equivalent at 12 Months [ Time Frame: Week 0, Week 26, Week 52 ]
  • Change from Baseline in Bayley Scale of Infant Development, Fourth Edition (Bayley-4) Fine Motor Growth Score Equivalent at 12 Months [ Time Frame: Week 0, Week 26, Week 52 ]
  • Change from Baseline in Bayley Scale of Infant Development, Fourth Edition (Bayley-4) Gross Motor Growth Score Equivalent at 12 Months [ Time Frame: Week 0, Week 26, Week 52 ]

Central Contacts and Locations

Central contacts

Riley Shubb

781-860-1711MGHGLOW-AS@mgb.org

Leena Phan

781-860-1711MGHGLOW-AS@mgb.org

Locations

MGH Lurie Center for Autism

Recruiting

Lexington, Massachusetts, United States, 02421

Contacts

Riley Shubb

781-860-1711MGHGLOW-AS@mgb.org

Leena Phan

781-860-1711MGHGLOW-AS@mgb.org

Principal Investigator:

Christopher J Keary, MD

More Information

Sponsor

Massachusetts General Hospital

Last update posted

Aug 21, 2026

Last verified

Aug, 2026

Keywords

  • Angelman syndrome
  • Angelman
  • GLOW-AS
  • AS
  • Natural History
  • Sleep

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Massachusetts General Hospital on 2026-08-21.