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Angelman Syndrome (AS)

Rare genetic disorder that mainly affects the nervous system

What is Angelman Syndrome? 

Angelman Syndrome is a genetic, neurological disorder characterized by significant developmental delays, intellectual disability, epilepsy and problems with speech, sleep, and motor coordination and balance (ataxia).1 Symptoms are normally present after 6 months of age.

The timely diagnosis of Angelman Syndrome is difficult, and it may be misdiagnosed since other syndromes have similar characteristics.3 People with Angelman Syndrome require life-long care, intense therapies to help develop functional skills and improve their quality of life, and close medical supervision involving multiple interventions. However, life expectancy does not appear to be reduced.2

How Common is Angelman Syndrome?  

We estimate that Angelman’s Syndrome affects 22,000 people in the U.S., and up to 500,000 worldwide. It affects all races and genders equally.4,3,4

How is PTC Working to Treat Angelman Syndrome? 

PTC’s gene therapy platform includes PTC-AS for the treatment of Angelman Syndrome, which has orphan drug designation. In preclinical studies, PTC-AS delivers a working version of the targeted gene to nerve cells in the brain and spinal cord, thereby increasing the production of the affected protein.


[1] Mathews JM, Cook EK, Margolis SS, Williams CA (2020) Chapter 24 – Angelman syndrome. In RN Rosenberg, JM Pascual, in Rosenberg’s Molecular and Genetic Basis of Neurological and Psychiatric Disease (Sixth Edition) (pp. 349–361). Cambridge, MA: Academic Press Elsevier Science.

[2] Dagli AI, Mueller J, Williams CA. (1998) Angelman syndrome. In: Adam MP, Ardinger HH, Pagon RA, et al. in GeneReviews® [Internet]. Seattle (WA): University of Washington. Available from: Accessed September 2021.

[3] Dagli A, Buiting K, Williams CA. Mol Syndromol 2012;2(3–5):100–112.

[4] Steffenburg S, Gillberg CL, Steffenburg U, et al. Pediatr Neurol 1996;14(2):131–136.

How Can You Stay Informed About Angelman Syndrome? 

If you wish to speak to us regarding our therapeutic approach, please reach out.