Learn About Angelman Syndrome

What is the definition of Angelman Syndrome?

Angelman syndrome (AS) is a genetic condition that causes problems with the way a child's body and brain develop. The syndrome is present from birth (congenital). However, it often isn't diagnosed until about 6 to 12 months of age. This is when development problems are first noticed in most cases.

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What are the causes of Angelman Syndrome?

This condition involves the gene UBE3A.

Most genes come in pairs. Children receive one from each parent. In most cases, both genes are active. This means information from both genes is used by the cells. With the UBE3A gene, both parents pass it on, but only the gene passed on from the mother is active.

Angelman syndrome most often occurs because UBE3A passed on from the mother doesn't work the way it should. In some cases, AS is caused when two copies of UBE3A gene come from the father, and none come from the mother. This means neither gene is active, because they both come from the father.

What are the symptoms of Angelman Syndrome?

In newborns and infants:

  • Loss of muscle tone (floppiness)
  • Trouble feeding
  • Heartburn (acid reflux)
  • Trembling arm and leg movements

In toddlers and older children:

  • Unstable or jerky walking
  • Little or no speech
  • Happy, excitable personality
  • Laughing and smiling often
  • Light hair, skin, and eye color compared to rest of family
  • Small head size compared to body, flattened back of head
  • Severe intellectual disability
  • Seizures
  • Excessive movement of the hands and limbs
  • Sleep problems
  • Tongue thrusting, drooling
  • Unusual chewing and mouthing movements
  • Crossed eyes
  • Walking with arms uplifted and hands waving

Most children with this disorder don't show symptoms until about 6 to 12 months. This is when parents may notice a delay in their child's development, such as not crawling or starting to talk.

Children between 2 and 5 years of age start to show symptoms such as jerky walking, happy personality, laughing often, no speech, and intellectual problems.

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What are the current treatments for Angelman Syndrome?

There is no cure for Angelman syndrome. Treatment helps to manage health and development problems caused by the condition.

  • Anticonvulsant medicines help control seizures
  • Behavior therapy helps manage hyperactivity, sleep problems, and development problems
  • Occupational and speech therapy manage speech problems and teach living skills
  • Physical therapy helps with walking and movement problems
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What are the support groups for Angelman Syndrome?

Angelman Syndrome Foundation: www.angelman.org

AngelmanUK: www.angelmanuk.org

What is the outlook (prognosis) for Angelman Syndrome?

People with AS live close to a normal lifespan. Many have friendships and interact socially. Treatment helps improve function. People with AS can't live on their own. However, they may be able to learn certain tasks and live with others in a supervised setting.

What are the possible complications of Angelman Syndrome?

Complications may include:

  • Severe seizures
  • Gastroesophageal reflux (heartburn)
  • Scoliosis (curved spine)
  • Accidental injury due to uncontrolled movements
When should I contact a medical professional for Angelman Syndrome?

Call your health care provider if your child has symptoms of this condition.

How do I prevent Angelman Syndrome?

There is no way to prevent Angelman syndrome. If you have a child with AS or a family history of the condition, you may want to talk with your provider before becoming pregnant.

What are the latest Angelman Syndrome Clinical Trials?
An Open-Label, Multicenter Study To Investigate The Safety, Tolerability, Pharmacokinetics And Pharmacodynamics Of RO7248824 In Participants With Angelman Syndrome

Summary: This is a Phase I, multicenter, non-randomized, adaptive, open label, multiple ascending, intra-participant, dose-escalation study with an LTE part. The objective of the study is to investigate the safety, tolerability, PK and PD of RO7248824 in participants administered IT with AS. Two linked sets of dose escalation cohorts are planned based on two different age groups, namely participants with A...

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A Phase IIa Multicenter, Open-Label, 12-Week Study to Investigate the Pharmacokinetics and Safety and to Provide Proof of Mechanism of Alogabat in Children and Adolescents Aged 5-17 Years With Angelman Syndrome (AS) With Deletion Genotype

Summary: This is a two-part, Phase IIa, multicenter, 12-week, open-label study. Up to 56 participants with deletion Angelman Syndrome (AS) aged 5-17 years (inclusive) will be enrolled in the study.

What are the Latest Advances for Angelman Syndrome?
Therapeutic approach to neurological manifestations of Angelman syndrome.
Genetic analysis of a case with mosaicism of a small supernumerary marker chromosome derived from idic(15).
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SPG6 (NIPA1 variant): A report of a case with early-onset complex hereditary spastic paraplegia and brief literature review.
Who are the sources who wrote this article ?

Published Date: July 30, 2021
Published By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

What are the references for this article ?

Dagli AI, Mathews J, Williams CA, et al. Angelman syndrome. In: GeneReviews. Seattle (WA): University of Washington, Seattle; 1993-2022. 1998 Sep 15 [updated 2021 Apr 22]. PMID: 20301323 pubmed.ncbi.nlm.nih.gov/20301323/.

Kumar V, Abbas AK, Aster JC. Genetic and pediatric diseases. In: Kumar V, Abbas AK, Aster JC, eds. Robbins Basic Pathology. 10th ed. Philadelphia, PA: Elsevier; 2018:chap 7.

Madan-Khetarpal S, Arnold G, Ortiz D. Genetic disorders and dysmorphic conditions. In: Zitelli BJ, McIntire SC, Nowalk AJ, Garrison J, eds. Zitelli and Davis' Atlas of Pediatric Physical Diagnosis. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 1.

Nussbaum RL, McInnes RR, Willard HF. The chromosomal and genomic basis of disease: disorders of the autosomes and sex chromosomes. In: Nussbaum RL, McInnes RR, Willard HF, eds. Thompson & Thompson Genetics in Medicine. 8th ed. Philadelphia, PA: Elsevier; 2016:chap 6.