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Angelman Syndrome


Angelman Syndrome  is found in 1 of 10,000 births. It is a micro deletion syndrome affecting chromosome 15 involves a process of genomic imprinting where a sequence of genes from the maternal chromosome are silencing the critical corresponding genes from the fathers chromosome so that the end result is a defective chromosomal gene sequence in that region. This interferes with the fetal development and results in a series of changes in the person born with this chromosomal abnormality. The mirror image micro deletion syndrome of Angelman Syndrome is the Prader Willi syndrome, where the deletion of 15q11-q13 is paternally derived.

Signs and symptoms

In the case of Angelman syndrome there is a small head (microcephaly) and the individuals have mental retardation. Here is an image of a child with Angelman syndrome. Their movements are puppet-like, but not truly ataxic. A person with Angelman syndrome will frequently burst out in uncontrollable laughter. Seizures are also common and EEG recordings between seizures will show a characteristic pattern of bifrontal runs of notched slow waves. Sleep EEG’s show slow and sharp waves. The brain has normally folded surfaces (normal gyral development), but a mildly thinned grey matter layer (brain atrophy). The cerebellum shows marked atrophy.


As this is a genetic syndrome, there is at present no treatment available. These individuals need to live in a supportive environment and often end up in a special home that has equipment to deal with these patients.

 Angelman Syndrome (Baby With Small Head)

Angelman Syndrome (Baby With Small Head)


1. Cerebral Palsy due to Chromosomal Anomalies and Continuous Gene Syndromes: Clinics in Perinatology – Volume 33, Issue 2 (June 2006) – Copyright © 2006 W. B. Saunders Company

2. Behrman: Nelson Textbook of Pediatrics, 17th ed., © 2004 Saunders: Chapter 70 – Chromosomal Clinical Abnormalities

Last modified: March 5, 2023

This outline is only a teaching aid to patients and should stimulate you to ask the right questions when seeing your doctor. However, the responsibility of treatment stays in the hands of your doctor and you.