The biological mechanism behind Rett Syndrome may be less complicated than previously thought, according to scientists at the University of Edinburgh. Their findings provide insight into the autistic spectrum disorder, which leaves sufferers with severe speech and mobility problems and affects more than 1000 children in the UK.Rett Syndrome primarily affects girls and is caused by mutations in the X-chromosome gene, MeCP2. Previously it was thought that MeCP2 protein affected the expression of a handful of genes, but this study, published in the journal Molecular Cell, claims that the protein may act "˜genome-wide' within brain cells.Professor Adrian Bird, who led the research team, said: "This debilitating disorder is caused by a protein that is much more abundant in brain cells than we had realised and can therefore interact with the entire human genome, rather than with a few selected genes.""It may be that, in Rett patients, many brain cells share a generic defect "“ which would mean this disease is less complicated than we feared. More work is needed to investigate this possibility."