Potential treatment, following on from the research, could range from overriding the mutated version of MECP2 with the activation of a healthy version of the gene. Alternatively, therapy could focus on drug treatment to inhibit the action of proteins expressed as a result of a MECP2 mutation.

Chris James, director of Rett Syndrome Association UK, said: "The Rett Syndrome Association UK is extremely delighted to hear about the results of Professor Bird's research. This is a very significant step on the road for future therapeutic approaches to Rett syndrome and, whilst the work in this area is still at an early stage, it will give hope to those families affected by Rett syndrome. It is particularly pleasing for us that we have been able to help fund this research that could have such a positive benefit for people with Rett syndrome, their families and carers."