Abnormal Movements in Angelman Syndrome

Quick Overview

Dr. Robert Carson from Vanderbilt Children’s in Nashville has been working to understand movement disorders in Angelman Syndrome. The disorders range from benign stereotypical movements to tremors, seizures, ataxia, and non-epileptic myoclonus. The team has collected survey and video data from patients, with the aim of creating a library of examples for better understanding. Initial findings suggest that abnormal movements may worsen when patients are constipated, have not had good sleep, or around the time of periods in female patients. The primary movement disorder type in nine out of 16 patients was felt to be dystonia, a disorder not commonly associated with Angelman Syndrome. The team suggests that aggressive management of constipation and sleep issues, and considering hormonal therapies for women, may help manage these movement disorders. They also encourage families to capture videos of these movements to aid local providers in understanding and treating them.


Good morning to all my Angelman family and friends. I’m Dr. Robert Carson from Vanderbilt Children’s in Nashville, where I now direct the Angelman and Dup15q Clinic. The goal of this talk is to update you on some of the work we’ve been doing to better understand movement disorders and Angelman Syndrome.

Understanding Movement Disorders in Angelman Syndrome

As this audience well knows, there’s a variety of movements, some abnormal, some not, in Angelman Syndrome that can be quite disruptive. They range from the more benign and normal stereotypes or stereotypical movements, the happy dance, if you will, to tremors, and of course seizures, ataxia, and then non-epileptic myoclonus.

Our goal was to better understand non-epileptic myoclonus. And of course, through better understanding, we can better develop therapies that help mitigate it. One of the key challenges we face is that we’re trying to make sure that we’re all talking about the same thing.

The Challenge of Defining Abnormal Movements

The purpose of using a more generic term is to not put a name to something before we fully understand what it is. So given that we’re discussing abnormal movements, which don’t necessarily fit the classic abnormal movements described in the literature, this has been a bit more challenging.

Non-Epileptic Myoclonus

Much of the work today on non-epileptic myoclonus has been out of Ron Thibert’s group in Mass General. And the working definition or paroxysms or episodes of myoclonus, mostly in the hands, can involve the legs as well. These can last from seconds to hours to all day, and I think our data reflects that as well.

Impact of Abnormal Movements

Relevant to this audience is that this is something that increases as our children age, affecting greater than 60% of Angelman patients beyond 35 years of age. And again, as you’re aware, this can be very disruptive. Some families report that it impacts their child’s ability to swallow, to walk, or talk, and they cry and get upset when these happen.

Our Approach to Understanding These Movements

The approach we took to better understand these movements is to collect survey data and to collect video data. And at the time that we started this was, of course, right in the middle of the COVID pandemic. So we were trying to design a study that was user-friendly, that limited the need to travel, and that people from a variety of locations could participate.

Future Plans

In the future, we hope to have a library available so everybody can look at video examples and say, oh, that’s an example of a seizure, that’s an example of myoclonus, et cetera. So far we’ve had a total of 47 surveys that we’ve collected and videos that we’ve analysed from 20 patients.


Of course, I would love to say today that I have the magic bullet that will make all movement disorders go away in Angelman syndrome. And I think the one thing that everyone can do now that I think may help is to be aggressive with what you’re already doing. And that means working on constipation, continue to explore options to improve sleep.

And then if your child is a woman, and definitely if symptom exacerbations correlate with the time of her period, then hormonal therapies may be an option that could have important benefit. Obviously, as we explore our data more and think more broadly, we may be able to come up with other treatment options.

Thank you all for listening. And of course, I would like to throw out additional thank you to the Angelman Syndrome Foundation and specifically the families who have both supported this work. And for all the families who have taken the time to submit survey information as well as submitted videos. So thank you all. Hope to talk to you all shortly. Have a great day.

Talk details

  • Title: Abnormal Movements in AS
  • Author(s): Robert Carson
  • Author(s)’ affiliation: Vanderbilt University
  • Publication date: 2023-07-07
  • Collection: 2023 ASF Virtual Conference