U.S. flag

An official website of the United States government

GTR Home > Tests > UBE3A Gene Sequencing


This is a clinical test intended for Help: Diagnosis, Mutation Confirmation, Risk Assessment, Screening

Clinical summary


Imported from GeneReviews

Angelman syndrome (AS) is characterized by severe developmental delay or intellectual disability, severe speech impairment, gait ataxia and/or tremulousness of the limbs, and unique behavior with an apparent happy demeanor that includes frequent laughing, smiling, and excitability. Microcephaly and seizures are also common. Developmental delays are first noted at around age six months; however, the unique clinical features of AS do not become manifest until after age one year.

Clinical features


Imported from Human Phenotype Ontology (HPO)

  • Cerebellar ataxia
  • Constipation
  • Drooling
  • Exotropia
  • Macroglossia
  • Wide mouth
  • Hypotonia
  • Myopia
  • Nystagmus
  • Obesity
  • Scoliosis
  • Seizure
  • Intellectual disability, severe
  • Strabismus
  • EEG abnormality
  • Hyperreflexia
  • Hypopigmentation of the skin
  • Brachycephaly
  • Clumsiness
  • Limb tremor
  • Hypoplasia of the maxilla
  • Protruding tongue
  • Delayed ability to walk
  • Mandibular prognathia
  • Deeply set eye
  • Hyperactivity
  • Secondary microcephaly
  • Global developmental delay
  • Blue irides
  • Broad-based gait
  • Flat occiput
  • Paroxysmal bursts of laughter
  • Progressive gait ataxia
  • Widely spaced teeth
  • Intellectual disability, progressive
  • Fair hair
  • Motor delay
  • Absent speech
  • Happy demeanor
  • Generalized hypotonia
  • Feeding difficulties in infancy
  • Cerebral cortical atrophy
  • Sleep-wake cycle disturbance
Show all

Conditions tested

Target population


Patients with a diagnosis of Angelman syndrome


Not provided

Clinical validity


Not provided

Clinical utility


Establish or confirm diagnosis

IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.