Association of chromosomal aberration der(1;7)(q10;p10) with GATA2 deficiency and MDS. (A) Left: schematic representation of the mechanism leading to the formation of unbalanced der(1;7) aberration that results in trisomy 1q and deletion 7q. Right: copy number variation profiling based on whole genome sequencing data of the patient P15 depicting gain of material of 1q and loss of material of 7q, indicated by red arrows. (B) Composition of the study cohort. Within the EWOG-MDS primary MDS cohort, 13 cases with the der(1;7) were encountered, 8 of which had germline GATA2 mutations. An additional 17 cases with GATA2-related MDS and der(1;7) were enrolled from collaborating institutions for a more comprehensive analysis. (C) Matrix plot depicting clinical and genetic data of GATA2-MDS patients with der(1;7). (D) Dynamics of der(1;7) clone. Spontaneous regression or loss of the der(1;7) as well as phenotype changes over the course of disease are shown. AML with MRC, acute myeloid leukemia with myelodysplasia-related changes; Dx, diagnosis; EWOG-MDS, European Working Group of MDS in Childhood; last FUP, last follow-up; MDS-EB, MDS with excess blasts; MDS-MLD, MDS with multilineage dysplasia; mut, mutated; no, number; RCC, refractory cytopenia of childhood; WT, wild type.