FLT3 and acute myeloid leukemia: First, we used our published sorting strategy to isolate rare pre-leukemic HSCs from AML patient samples that contain the DNMT3AR882H mutation, but lack the leukemic NPM1c and/or FLT3-ITD mutations.12,22 After isolation by flow cytometry, cells were electroporated with an R882H-specific single guide RNA (sgRNA) pre-complexed with Cas9 protein and transduced with recombinant adeno-associated vector (rAAV6) encoding either the wildtype DNMT3AR882 codon (correction) or, as a control, the mutant DNMT3AR882H codon (re-mutation, Figure 1A, S1).