MLLT1 and Wilms tumor: To investigate the pathogenic role of the ENL YEATS domain tumor mutations in kidney development, we generated conditional knock-in mouse models for two frequent mutations: Enl117_118insNHL (hereafter named EnlT1), the most prevalent ENL insertion mutation found in Wilms tumor, and Enl111_113NPP>K (also named as EnlT3), a small deletion mutation19,20 (Fig. 1a).