A different mutation in JAK2 gene in a patient with Down syndrome associated precursor B-cell lymphoblastic leukemia was reported by Malinge et al., This mutation was in-frame deletion of five-amino acid residues from position 682 to 686, named as IREED mutation, in the pseudokinase domain of JAK2. The gene discussed is JAK2; the disease is precursor B-cell acute lymphoblastic leukemia.