Home/What is Angelman syndrome

What is Angelman syndrome?

What is Angelman syndrome?

Angelman syndrome is a rare neurogenetic disorder that affects the nervous system, causing developmental delays, significant challenges with speech and communication, and difficulties with movement and balance. Many individuals also experience seizures and sleep disturbances.

Angelman syndrome is caused by a loss of function of the UBE3A gene in the brain. While individuals living with Angelman syndrome share certain characteristics, each person has their own abilities, strengths, and needs.

Estimated individuals worldwide
1 in 0
chromosome impacted in Angelman syndrome
0
Estimated individuals living with Angelman syndrome worldwide
0

Symptoms of Angelman Syndrome

Angelman syndrome can affect development, communication, movement, sleep, and behavior. While certain characteristics are common, symptoms and their severity vary from person to person.

Developmental Delays

Developmental milestones are often delayed, with differences typically becoming noticeable during the first year of life.

Limited or no verbal speech

Many individuals use gestures, vocalizations, signs, or communication devices to express themselves.

Balance and coordination difficulties

Challenges with balance, coordination, and walking are common.

Behavioral Characteristics

Frequent laughter, smiling, and social engagement are common characteristics.

Seizures

Seizures often begin in early childhood and can vary in frequency and severity.

Sleep difficulties

Difficulty falling asleep, staying asleep, or getting enough sleep is common.

What causes Angelman syndrome?

Angelman syndrome is caused by a loss of function of the UBE3A gene in the brain. This gene, located on chromosome 15, produces a protein that plays an important role in normal brain development and function.

In certain brain cells, only the copy inherited from the mother is normally active. When that copy is missing or not working properly, the brain does not produce enough functional UBE3A protein.

What are the types of Angelman syndrome?

There are multiple different mechanisms or genetic differences that can result in the absence of UBE3A protein. In AS, we call these different genetic mechanisms “genotypes.” Knowing your loved one’s AS genotype is important. While each individual living with AS is unique, individuals living with the same genotype may have certain characteristics in common.

Each genotype has a different chance to be inherited. Finally, many clinical trials have genotype in their inclusion criteria for enrollment.

Neurotypical*

*For comparison, not a genotype
In neurotypical individuals who do not have Angelman syndrome, the UBE3A gene from the egg is turned on in neurons, while the UBE3A gene from the sperm is turned off.

Deletion (70%)

The most common cause of Angelman syndrome is a deletion, or missing section on the chromosome 15 that came from the egg. This missing section includes the UBE3A gene plus about 10 other genes. When the maternal UBE3A gene is missing and the paternal UBE3A gene is turned off, no UBE3A is made in the neurons.
Learn more about Deletion AS

Mutation (10%)

Mutations within the UBE3A gene from the egg cause about 10-15% of AS. A mutation is a difference or variant within the DNA that results in no UBE3A protein or UBE3A protein that is less functional or nonfunctional.
Learn more about Mutation AS

Uniparental Disomy (UPD) (~5%)

UPD AS happens when both copies of chromosome 15 came from the sperm. Because the paternal UBE3A gene is always turned off in neurons, when both copies of chromosome 15 come from the sperm, both UBE3A genes are turned off, and no UBE3A protein is made in the brain.
Learn more about UPD AS

Imprinting Center Defect (ICD) (~2-3%)

An imprinting center defect (ICD) is when the maternal imprinting center does not work correctly, and as a result the maternal UBE3A gene is incorrectly turned off. Because the paternal UBE3A gene is always turned off in neurons, an ICD on the maternal chromosome 15 results in no UBE3A protein being made. ICDs can be caused by a deletion of the AS imprinting center or an error at the AS imprinting center.
Learn more about ICD AS

Mosaic (1%)

When the genetic difference that causes AS occurs after fertilization, during the development of an embryo, the person lives with Mosaic AS. A person living with Mosaic AS has some cells that make UBE3A and some cells that do not make UBE3A in their body.
Learn more about Mosaic AS

What is the life expectancy for someone living with Angelman syndrome?

Many individuals living with Angelman syndrome have a typical lifespan, but there are factors associated with Angelman syndrome that could potentially impact a person’s lifespan.

Is there a cure or treatment for Angelman Syndrome?

Currently, treatments for Angelman syndrome are generally targeted to the symptoms each individual is experiencing. For example, individuals experiencing seizures should receive treatment(s) directed at reducing or eliminating the seizures. In 2022, a consensus statement on care in AS was published, offering valuable guidance to health care providers about managing symptoms and preventative care for individuals living with Angelman syndrome.

There is currently no cure for Angelman syndrome. However, research is actively progressing, aimed at developing potential therapeutics to improve symptoms and addressing the underlying cause of AS, the missing UBE3A protein in the brain.  The Drug Development Pipeline provides information on potential therapeutics that are still in early stage development as well as current ongoing clinical trials.

Research, drug development, and clinical trials

Drug Development Pipeline

 Want to learn more about the development of potential treatments for Angelman syndrome? The Drug Development Pipeline is an interactive tool that can be used to see an overview of potential Angelman syndrome therapeutics, or enable a deep dive into a specific program or clinical trial. 

Participate in Clinical Trials

Interested in finding clinical trials? Clinical trials are research studies designed to test whether a specific potential treatment or device is safe and effective at treating a condition or symptom.

Roadmap to a Cure

At FAST, we know we need as many therapeutic options as possible. To make it easier to understand how we think about therapeutic development, we’ve developed the Roadmap to a Cure, as a way to think about the different potential approaches to treating AS.

Research Model

At the core of FAST’s mission is a commitment to bring scientific and therapeutic advancements from benchside to bedside. Learn more about FAST’s research model and why we stand out in the rare disease community.

Community Resources

Meet with Niki

Questions about AS genetic testing or a test report? Wondering about chances for your family? Interested in understanding your loved one’s genotype and what it means for clinical trials? Schedule a free conversation with FAST’s certified genetic counselor.

New to FAST

New to Angelman syndrome or to FAST? If you are new to the diagnosis of Angelman syndrome, there are two things you should know – you are not alone and THERE IS HOPE. Register with our New to FAST program to receive resources and connections. FAST is a big community, here to surround you with love, support, and strength.

Get Involved

There are so many ways to support FAST and our mission. Whether it’s your time, talent, or treasure, we encourage you to join in a way that inspires you.

Find an Event

Join FAST at our annual Global Science Summit & Gala in November or advocate with us on Capitol Hill in March. Or make new friends and support an event for a great cause at a local fundraiser. 

Frequently Asked Questions

Most of the time, no. Angelman syndrome is most often caused by a brand new genetic change that happened prior to conception and is not inherited from a parent. However, some genotypes have a higher chance to run in the family and testing the parents may be recommended. If you have questions about whether AS runs in your family, reach out to FAST’s genetic counselor

Currently, the diagnosis of Angelman syndrome is made based on genetic testing. Genetic testing for AS can be complicated. It typically requires more than one test to confirm the genotype or to rule out the condition. Learn more about genetic testing in Angelman syndrome

Yes. Every person living with Angelman syndrome is unique in what symptoms they experience and in how they learn and develop. Knowing the genotype can provide some information on what to expect, but even within a genotype, individuals can vary in their abilities and medical issues.

For example, individuals living with Deletion AS have the highest chance to have seizures. However, even within Deletion AS, some individuals may never have a seizure, some individuals may only have a seizure once with a fever, some individuals have frequent seizures that are well-controlled with medicines, and some individuals have difficult to control seizures.

FAST’s mission is simple: Cure Angelman syndrome. As the largest non-governmental funder of Angelman syndrome research in the world, our goal is to drive forward transformative research and development programs for those living with Angelman syndrome – regardless of age or genotype.

There are so many ways to lean into this effort. Whether it’s your time, talent, or treasure, we encourage you to join in a way that inspires you.

  1. Advocacy
  2. Fundraise 
  3. Join our Running Team
  4. Connect with us if you have something else in mind 

Yes! There are ongoing clinical trials to test the safety and effectiveness of several different potential treatments for AS happening right now. There are also several other potential therapy approaches that are in earlier stages of development, meaning that they are still being tested in cells and animal models. Visit the Drug Development Pipeline to learn more.

In AS, the unique nature of the UBE3A gene offers a promising opportunity for potential therapies. Due to UBE3A‘s imprinting, individuals living with AS usually have a functional paternal copy of the UBE3A gene. This presents an exciting possibility: the paternal UBE3A gene could potentially be “turned on” to enable the production of UBE3A protein. As a result, there are therapeutic approaches that could address the underlying cause of AS that may not be possible in other similar genetic conditions. Traditional strategies used in genetic disorders, such as gene replacement therapy or enzyme replacement therapy, remain potential therapeutic options as well.

Still have questions? Contact Us

What are you looking for?

Find information on Angelman syndrome, research, clinical trials, resources, and ways to get involved.