Rett Syndrome is a very serious autism-spectrum disorder. Symptoms appear 6-18 months following birth when the child enters a “crisis” usually accompanied by a marked deceleration of head growth severe problems with language, movement and breathing and susceptibility to seizures and scoliosis of the spine. This condition is caused by a faulty gene and since the gene is on the X chromosome, the condition overwhelmingly affects girls. There are currently 2,400 patients with Rett syndrome in the UK and there is no cure for the disorder. Treatment is focused on management of the symptoms present in individual cases and this can involve extensive occupational therapy, medication and surgery. Patient survival is dependent on intensive lifelong support. In this study, researchers will reactivate the gene in a mouse model of Rett syndrome. Initial laboratory work by this team suggests that many of the symptoms of the disease could be corrected by gene therapy. Further work is now needed to determine the best way of repairing or replacing the faulty gene and which cells should be targeted. This research aims to demonstrate that Rett syndrome could be treatable using gene therapies in the future.