What are the conditions of having angelman syndrome?”
Angelman syndrome (AS) is a neuro-genetic disorder characterized by intellectual and developmental delay, sleep disturbance, seizures, jerky movements especially hand-flapping, frequent laughter or smiling, and usually a happy demeanour. AS is a classic example of genetic imprinting in that it is usually caused by deletion or inactivation of genes on the maternally inherited chromosome 15. The sister syndrome, Prader-Willi syndrome, is caused by a similar loss of paternally-inherited genes. AS is named after a British pediatrician, Dr. Harry Angelman, who first described the syndrome in 1965.