Angelman syndrome (AS) is a genetic disorder that causes neurological and psychological problems including seizures, difficult behaviors, movement disorders, and sleep problems. Gastrointestinal, orthopedic, and eye problems also are often present. Infants with AS appear normal at birth but often have feeding problems in the first months of life and exhibit noticeable developmental delays by 6-12 months. Seizures often begin between 2-3 years of age and occur in 80-85 percent of those with AS.
Features that help define the syndrome include very happy demeanor with frequent laughter, poor balance, tremor, and minimal to no speech. The disorder results from the absence of the UBE3A gene inherited from the mother. The gene provides instructions for a protein that plays a critical role in the normal development and function of the nervous system.
There are four types of Angelman syndrome involving problems with chromosomes or mutations in the UBE3A gene. Other children may have a genetic syndrome that looks like AS but is caused by a different gene. Dr. Harry Angelman first reported the syndrome in 1965, when he described three children in his practice with similar symptoms.
Most individuals with Angelman syndrome will have significant developmental delays, speech limitations, and motor difficulties, but they understand much of what is said and often learn to communicate non-verbally and by using communication devices. Those with gene deletions are more severely affected, whereas those with non-deletions typcally make more developmental progress with better communications skills. Individuals with AS appear to have normal life spans and generally do not show developmental regression as they age.
As individuals move into adolescence and adulthood, seizures improve or resolve for most people, sleep tends to improve but is still an issue for many, and gastrointestinal symptoms do not change much over time. Anxiety tends to worsen after puberty and can lead to difficult behaviors. Many teens and adults with AS also have frequent twitching in their hands, called myoclonus, which can spread to their arms and the rest of the body. Myoclonus is not seizure activity but can interfere with quality of life and may be treated with medication.
There is no specific therapy for Angelman syndrome at this time. The best treatment is to minimize seizures, anxiety, and gastrointestinal issues and maximize sleep. Seizures are treated with medications and dietary therapies, while sleep issues are treated with medications and sleep training.
It is also important to test for and treat any problems with vision, hearing, and mobility. Intensive therapies such as physical, occupational, and speech therapies are critical to begin early and continue as long as necessary. Applied behavior analysis and/or behavior therapy also are important for many individuals.