Genetic analysis was performed on five patients, including the present study (Ph + B-ALLIKZF1+/DDX41dm), two cases of Ph + B-ALL accompanying IKZF1 deletion without DDX41 mutation (Ph + B-ALLIKZF1+/DDX41−), one case of AML with double DDX41 mutation (AMLDDX41 dm), and one case of normal BM, whom were examined for HM at Soonchunhyang University Seoul Hospital, South Korea, from November 2018 to May 2020. Here, DDX41 is linked to acute lymphoblastic leukemia.