What is Angelman Syndrome?
Angelman syndrome is a complex genetic disorder that primarily affects the nervous system. Characteristic features of this condition include delayed development, intellectual disability, severe speech impairment, and problems with movement and balance (ataxia). Most affected children also have recurrent seizures (epilepsy) and a small head size (microcephaly). Delayed development becomes noticeable by the age of 6 to 12 months, and other common signs and symptoms usually appear in early childhood.
Angelman syndrome is caused by a missing or “faulty” genetic code on chromosome #15. To date, there are four distinct known genetic causes for AS that can be determined by genetic testing. These four separate diagnoses, which all cause the same syndrome, but with some variations in the symptoms, are as follows: deletion+, uniparental disomy (UPD), imprinting and UBE3A, which is the only hereditary diagnosis and a clinical diagnosis;
Children with Angelman syndrome typically have a happy, excitable demeanor with frequent smiling, laughter, and hand-flapping movements. Hyperactivity, a short attention span, and a fascination with water are common. Most affected children also have difficulty sleeping and need less sleep than usual.
With age, people with Angelman syndrome become less excitable, and the sleeping problems tend to improve. However, affected individuals continue to have intellectual disability, severe speech impairment, and seizures throughout their lives.
Seizures often begin between 2 and 3 years of age; Speech impairment is pronounced, with little to no use of words; Individuals with this syndrome often display hyperactivity, small head size, sleep disorders, and movement and balance disorders that can cause severe functional deficits; Individuals with Angelman Syndrome will require life-long care.
The physician Harry Angelman (syndrome named after him) first delineated the syndrome in 1965, when he described several children in his practice as having “flat heads, jerky movements, protruding tongues, and bouts of laughter.”;
Infants with Angelman syndrome appear normal at birth, but often have feeding problems in the first months of life and exhibit noticeable developmental delays by 6 to 12 months;