Recently, high throughput genome sequencing of a variety of cancers has identified inactivating mutations in the ATRX/DAXX/H3.3 complex in cells and tumours exhibiting the ALT phenotype, including pancreatic neuroendocrine tumours5, glioblastoma multiforme, oligodendrogliomas, medulloblastomas6 and neuroblastomas7. The gene discussed is ATRX; the disease is neoplasm.