This effect was also observed in MYCN hemizygous Runx1t1+/Y534H mice (Supplementary Fig. 1f), suggesting the Runx1t1Y534H mutation is a loss-of-function in the context of neuroblastoma development, and providing strong evidence for Runx1t1 having an important role in neuroblastoma tumorigenesis in this model. The gene discussed is MYCN; the disease is neuroblastoma.