A common underlying mechanism is shared by a group of previously unrelated disorders which all cause complex defects in brain development and function

Rett syndrome (RTT), Cornelia de Lange syndrome (CdLS) and Alpha-Thalassemia mental Retardation, X-linked syndrome (ATR-X) have each been linked with distinct abnormalities in chromatin, the spools of proteins and DNA that make up chromosomes and control how genetic information is read in a cell.