Angelman syndrome is a neurological genetic disorder that is characterized by symptoms such as frequent laughter without stimuli, delayed physical and mental development, seizures, and speech impediments in children.

The diagnosis of Angelman syndrome is usually given after a clinical evaluation of physical features and genetic testing for the missing or inactive maternal copy of the UBE3A gene.

In addition to genetic testing, positron emission tomography (PET) is a useful tool for understanding brain function and tracking biochemical and molecular processes in the nervous system of Angelman syndrome patients.

What is PET?

PET imaging or scanning uses small quantities of substances called radioactive tracers. These tracers accumulate in the site of injection or bind to certain molecules in the body and emit radiation. The radiation emitted is captured by the PET scanner and a computer reconstructs the image of the organ of interest, which is then interpreted by a radiologist.

While PET scans can reveal information not normally captured by magnetic resonance imaging (MRI) or computerized tomography (CT), doctors generally use a combined CT-PET approach for better diagnosis.

PET scan for Angelman syndrome

GABA (gamma-aminobutyric acid) is an inhibitory neurotransmitter or cell-signaling molecule in the brain that is responsible for feelings of calm and tranquility. It acts by binding to GABA-A receptors. The genetic information necessary to make these receptors is found on chromosome 15, the same chromosome where the UBE3A gene resides. In Angelman syndrome, the deletion of the maternal copy of the UBE3A also affects regions of the chromosome that code for the GABA-A receptor.

PET scanning can assess the functioning of these GABA-A receptors and show the loss of these receptors in specific regions of the brain. Alterations in the distribution pattern of the GABA-A receptors, as revealed by PET scanning, combined with results from genetic tests can help confirm a diagnosis of Angelman syndrome.

PET scanning with MRI can offer more insights into brain anatomy changes in Angelman syndrome — specifically myelination and any reduction in the volume of white matter in the brain.

How to prepare for a PET scan

A radiologist will give detailed instructions on how to prepare for a PET scan. Generally, strenuous exercise needs to be avoided a few days prior to the test, and food intake stopped a few hours before the scan.

Tell the radiologist beforehand about the medications you’re currently taking, any allergies you have, or if you’re currently breastfeeding.

 

Last updated: Oct. 5, 2019

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Angelman Syndrome News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. 

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Özge has a MSc. in Molecular Genetics from the University of Leicester and a PhD in Developmental Biology from Queen Mary University of London. She worked as a Post-doctoral Research Associate at the University of Leicester for six years in the field of Behavioural Neurology before moving into science communication. She worked as the Research Communication Officer at a London based charity for almost two years.