 In mice, the knockout mutation of Gabrb3 causes severe neonatal mortality with the cleft palate phenotype present, the survivors experiencing hyperactivity, lack of coordination and suffering with epileptic seizures.These mice also exhibit changes to the vestibular system within the ear, resulting in poor swimming skills, difficulty in walking on grid floors, and are found to run in circles erratically.Deletion of the GABRB3 gene results in Angelman syndrome in humans, depending on the parental origin of the deletion.