Diagnosis

Your child's doctor may suspect Angelman syndrome if your child has developmental delays and other signs and symptoms of the disorder, such as problems with movement and balance, small head size, flatness in the back of the head, and frequent laughter.

Confirming a diagnosis of Angelman syndrome requires taking a blood sample from your child for genetic studies.

A combination of genetic tests can reveal the chromosome defects related to Angelman syndrome. These tests may review:

  • Parental DNA pattern. This test, known as a DNA methylation test, screens for three of the four known genetic abnormalities that cause Angelman syndrome.
  • Missing chromosomes. Either a fluorescence in situ hybridization (FISH) test or a comparative genomic hybridization test (CGH) can show if portions of chromosomes are missing.
  • Gene mutation. Rarely, Angelman syndrome may occur when a person's maternal copy of the UBE3A gene is active, but mutated. If results from a DNA methylation test are normal, your child's doctor may order a UBE3A gene sequencing test to look for a maternal mutation.
Feb. 07, 2017
References
  1. NINDS Angelman syndrome information page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/angelman/angelman.htm. Accessed Nov. 7, 2016.
  2. National Library of Medicine. Angelman syndrome. Genetics Home Reference. http://ghr.nlm.nih.gov/condition/angelman-syndrome. Accessed Nov. 7, 2016.
  3. Angelman syndrome diagnostic criteria. Angelman Syndrome Foundation. http://www.angelman.org/understanding-as/medical-info/diagnostic-criteria/. Accessed Nov. 7, 2016.
  4. Pagon RA, et al., eds. Angelman syndrome. In: GeneReviews. Seattle, Wash.: University of Seattle, Washington; 1993-2016. http://www.ncbi.nlm.nih.gov/books/NBK1116. Accessed Nov. 7, 2016.
  5. Bailus BJ, et al. The prospect of molecular therapy for Angelman syndrome and other monogenic neurologic disorders. BMC Neuroscience. 2014;15:76.
  6. Angelman syndrome diagnostic testing. Angelman Syndrome Foundation. https://www.angelman.org/what-is-as/medical-information/diagnostic-testing/. Accessed Nov. 13, 2016.
  7. Buiting K, et al. Angelman syndrome — Insights into a rare neurogenetic disorder. Nature. 2016;12:584.
  8. Patterson MC (expert opinion). Mayo Clinic, Rochester, Minn. Nov. 22, 2016.