IKZF1 and common variable immunodeficiency: Three of the identified mutations, p.Arg143Trp, p.Cys150Arg, and p.Lys286* led to the disruption of IKAROS function and can explain the CVID phenotype with hypogammaglobinemia and B-cell defects via impairing the DNA binding ability of IKAROS and consequently the transcriptional regulation of B cell development and function.