This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.
|Medical Terms||Other Names||
|80%-99% of people have these symptoms|
Absent speech development
Lack of language development
Lack of speech
No speech development
No speech or language development
Nonverbal[ more ]
Psychiatric disturbances[ more ]
Short and broad skull
Wide based walk
|Cerebral cortical atrophy||
Decrease in size of the outer layer of the brain due to loss of brain cells
Mental retardation, progressive
Progressive mental retardation[ more ]
|Intellectual disability, severe||
Early and severe mental retardation
Mental retardation, severe
Severe mental retardation[ more ]
Abnormally large tongue
Increased size of tongue
Large tongue[ more ]
Big lower jaw
Increased projection of lower jaw
Increased size of lower jaw
Large lower jaw
Prominent lower jaw[ more ]
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference[ more ]
Low or weak muscle tone
|30%-79% of people have these symptoms|
|Hypoplasia of the maxilla||
Decreased size of maxilla
Decreased size of upper jaw
Small upper jaw
Small upper jaw bones
Upper jaw deficiency
Upper jaw retrusion[ more ]
No previous family history
Large mouth[ more ]
|Widely spaced teeth||
Widely-spaced teeth[ more ]
|5%-29% of people have these symptoms|
Squint eyes[ more ]
|Percent of people who have these symptoms is not available through HPO|
|Deeply set eye||
Deep set eye
Sunken eye[ more ]
Outward facing eye ball
Fair hair color
Flaxen hair color
Light colored hair
Sandy hair color
Straw colored hair
Towhead (hair color)[ more ]
|Feeding difficulties in infancy||0008872|
Decreased muscle tone
Low muscle tone[ more ]
More active than typical
|Hypopigmentation of the skin||
Patchy lightened skin
Involuntary shaking of limb
Nearsightedness[ more ]
Involuntary, rapid, rhythmic eye movements
Having too much body fat
|Paroxysmal bursts of laughter||0000749|
|Progressive gait ataxia||0007240|
Tongue sticking out of mouth[ more ]
Abnormal curving of the spine
|Sleep-wake cycle disturbance||0006979|
Several different genetic mechanisms can inactivate or delete the maternal copy of the UBE3A gene. Most cases of Angelman syndrome occur when a segment of the maternal
In a small percentage of cases, a person with Angelman syndrome inherits two copies of chromosome 15 from his or her father, instead of one copy from each parent. This is called paternal uniparental disomy. Rarely, Angelman syndrome can also be caused by a chromosomal rearrangement called a
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.
If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.
If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.
You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.
Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.
Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes hypsarrhythmia in West syndrome or the petit mal variant pattern in Lennox-Gastaut syndrome (see these terms). Other differential diagnoses include Rett syndrome, Mowat-Wilson syndrome, X-linked alpha-thalassemia-intellectual deficit syndrome (ATR-X), and 22q13 deletion syndrome (see these terms).
Visit the Orphanet disease page for more information.
Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.
Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question
How is Anglemans syndrome mistaken for Autism? See answer
We have a 2-year-old son who was diagnosed with Angelman syndrome. He has a deletion of the mother's part on chromosome 15. What are the chances of this syndrome occurring in our next baby? We have another 6-year-old son who is normal. See answer
What is the chance of having another child with Angelman syndrome if a mother has a translocation of chromosomes 15 and 7? Is there additional genetic testing that could be performed? See answer