In particular, the first patient displayed a history of acute lymphoblastic leukemia after immunotherapy (being in remission, but without any recovery of immunoglobulin levels more than 7 years after treatment), and the second patient was the brother of a proband with CVID carrying the same pathogenic IKZF1 (Ikaros) mutation (CVID13, OMIM #616873). Here, IKZF1 is linked to common variable immunodeficiency.