It is still not fully understood how genetic haploinsufficiency in del(5q) MDS contributes to malignant transformation of hematopoietic stem cells. We asked how compound haploinsufficiency for Csnk1a1 and Egr1 in the common deleted region on chromosome 5 affects hematopoietic stem cells. Additionally, Trp53 was disrupted as the most frequently co-mutated gene in del(5q) MDS using CRISPR/Cas9 editing in hematopoietic progenitors of WT, Csnk1a1-/+, Egr1-/+, Csnk1a1/Egr1-/+ mice. A …