A novel vector, composition and method of treating a neurological disorder characterized by deficient UBE3A is presented. The UBE3A gene, which encodes for E6-AP, a ubiquitin ligase, was found to be responsible for Angelman syndrome (AS). A unique feature of this gene is that it undergoes maternal imprinting in a neuron-specific manner. In the majority of AS cases, there is a mutation or deletion in the maternally inherited UBE3A gene, although other cases are the result of uniparental disomy or mismethylation of the maternal gene. A UBE3A protein construct was generated with additional sequences that allow the secretion from cells and uptake by neighboring neuronal cells. This UBE3A vector may be used in gene therapy to confer a functional E6-AP protein into the neurons and rescue disease pathology.