As expected, the group of genes we identified as the most frequent KMT2A fusion targets across our collection of samples included several genes that are known to be required for KMT2Ar leukemia, including HOXA9, MEIS1, MEF2C, MBNL1 and JMJD1C25–29 (Extended Data Fig. 3c and Supplementary Table 2). The gene discussed is MEF2C; the disease is leukemia.