Chapter 24 - Angelman syndrome

Abstract

Angelman syndrome (AS) is a neurodevelopmental disorder characterized by severe developmental delay and speech impairment, gait ataxia and/or tremulousness of limbs, microcephaly, seizures, and a unique behavior with a happy demeanor that includes frequent laughing, smiling, and excitability. AS is caused by the disruption of UBE3A that encodes E6-associated protein (E6AP) ubiquitin protein ligase. UBE3A shows parent-specific differential expression, or imprinting, limited to brain and spinal cord neurons. AS results from several genetic mechanisms that disrupt the functional allele of UBE3A inherited from the mother. While Ube3a-deficient mice help to elucidate the mechanisms by which loss of E6AP leads to synaptic dysfunction and AS pathophysiology, this remains an area of active investigation. Therapeutic approaches are now focused on the manipulation of related protein pathways of UBE3A and unsilencing of the paternal allele.