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Angelman syndrome

Angelman syndrome is a genetic disorder that primarily affects the nervous system. The disorder is named after Dr. Harry Angelman who first reported the syndrome in 1965.

Features that help define the disorder include:

  • Developmental delay
  • Intellectual disability
  • Severe speech impairment
  • Problems with movement and balance (ataxia)
  • Recurrent seizures (epilepsy)
  • Very happy demeanor with frequent laughter
  • A small head size (microcephaly)

Often, there are also gastrointestinal, orthopedic, and eye problems. Hyperactivity and a short attention span are common.

Infants with AS appear normal at birth but often have feeding problems in the first months of life. They also show developmental delays between the ages of 6 and 12 months. Seizures often begin between ages 2 and 3.

The disorder results from the loss of function of a gene called UBE3A, which provides instructions for making a protein (ubiquitin protein ligase E3A) that plays an important role in the development and function of the nervous system.

There is no specific therapy for AS. The focus of treatment is to reduce seizures, anxiety, and gastrointestinal issues and improve sleep. Seizures may be treated with medications and dietary therapies. Sleep issues may be treated with medications and sleep training. Physical, occupational, and speech therapies should begin early and continue as long as they are needed. Many people also may benefit from applied behavior analysis and/or behavior therapy.

Most people with AS will have significant developmental delays, speech limitations, and motor problems. They still will understand much of what is said. They also often learn to communicate non-verbally and with communication devices. People with AS appear to have normal life spans.

How can I or my loved one help improve care for people with Angelman syndrome?

Consider participating in a clinical trial so clinicians and scientists can learn more about AS and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with AS at

Where can I find more information about Angelman syndrome?

Information about AS may be available from the following resources:

Angelman Syndrome Foundation
Phone: 630-978-4245 or 800-432-6435

Phone: 866-783-0078

Prader-Willi Syndrome Association | USA
Phone: 941-312-0400

The Arc of the United States
Phone: 800-433-5255

More information is also available:

Genetic and Rare Diseases (GARD) Information Center


Content source: Accessed June 21, 2023.

The information in this document is for general educational purposes only. It is not intended to substitute for personalized professional advice. Although the information was obtained from sources believed to be reliable, MedLink, its representatives, and the providers of the information do not guarantee its accuracy and disclaim responsibility for adverse consequences resulting from its use. For further information, consult a physician and the organization referred to herein.

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