Angelman Syndrome

Angelman syndrome (AS) is characterized by severe developmental delay or mental retardation, severe speech impairment, gait ataxia, and a unique behavior that includes frequent laughing, smiling, and excitability. Microcephaly (small head size) and seizures are also common. Angelman syndrome affects an estimated 1 in 12,000 to 20,000 people. Angelman syndrome is caused by a deletion or disruption of the maternal chromosome 15q11-q13 gene region, and your doctor can order a DNA test for this condition. For more information, visit the Angelman Syndrome Foundation.