DDX3X and leukemia: The vast majority of validated sSNVs were observed at both time-points with only one leukemia case displaying mutations unique to the second time-point—a deletion in NOTCH1 and an sSNV in DDX3X. Although 13/871 of the sSNVs we observed were in recurrently mutated genes (Figure 2b, Supplementary Table 2), the vast majority were novel and likely passenger mutations.3