Angelman syndrome is a genetic disorder that causes various symptoms related to the central nervous system. Children who have Angelman syndrome typically appear normal at birth. However, they often begin to experience symptoms as early as 1 month of age that may eventually include mental retardation, severe speech impairment, disturbances in sleep and gait, and seizures, among others.

Children with Angelman syndrome also tend to exhibit a demeanor that is happy and excitable. They may engage in frequent smiling, excessive laughter and hand-flapping movements.

Humans have 23 pairs of chromosomes, and each chromosome carries multiple to hundreds of genes. Angelman syndrome results from a genetic problem related to a particular chromosome called chromosome 15. Mutations in the mother’s copy of a certain gene on this chromosome appear to cause most cases of Angelman syndrome. However, some cases of the syndrome appear to result from spontaneous genetic mutations.

Most cases of Angelman syndrome are diagnosed between the ages of 3 and 7, when symptoms begin to become obvious in the affected child. Both girls and boys are affected by the disorder. A physician will examine a child for characteristic signs and symptoms associated with Angelman syndrome. Laboratory testing known as chromosome analysis may also be performed.

There is no standard treatment for Angelman syndrome. Patients may receive various types of therapy, including speech therapy, occupational therapy and techniques to modify behavior and aid sleep. In addition, certain medications may be prescribed to treat symptoms of the disorder (e.g., anticonvulsant medications for seizures).