Angelman Syndrome

Angelman syndrome is a genetic disorder caused by loss of function of the maternally inherited UBE3A gene on chromosome 15, arising from a deletion, an inheritance of two paternal copies of the chromosome, or a direct mutation. It produces severe intellectual disability, little or no spoken language, an unsteady, jerky gait, and a notably happy demeanor with frequent laughter and smiling. British pediatrician Harry Angelman first described the condition in 1965 after observing several children with the same distinctive pattern of features.