Meanwhile, we also draw the following lessons from this case: (1) early maintenance therapy with gilteritinib after bridging allogeneic HSCT for refractory FLT3-mutated AML (successful engraftment and resume the therapy as soon as possible) and (2) allogeneic HSCT still carries a high risk of CNS relapse, especially in patients with FLT3 mutations, so risk-tailored prophylaxis is suggested. The gene discussed is FLT3; the disease is acute myeloid leukemia.