ATRX: Put Me on Repeat

Mutations in the chromatin-remodeling protein ATRX cause alpha thalassaemia and mental retardation, but the severity of the disorder is independent of the specific mutation. In this issue of Cell, demonstrate that ATRX alters gene expression by binding to G-rich tandem repeats, and the degree of transcriptional silencing caused by ATRX mutations correlates with the number of repeats.