ATRX and neoplasm: Intriguingly, ATRX mutations and ALT are also common in paragangliomas and pheochromocytomas57,58, and these tumours have frequent mutations in Krebs cycle genes, such as fumarate hydratase (FH) and succinate dehydrogenase (SDHx), leading to an accumulation of fumarate and succinate32,58,59.