Heterozygous variants in GATA2 contribute to DCML deficiency in mice by disrupting tandem protein binding

Malignant progression of preleukemic disorders

ABSTRACT

The spectrum of myeloid disorders ranges from aplastic bone marrow failure characterized by an empty bone marrow completely lacking in hematopoiesis to acute myeloid leukemia in which the marrow space is replaced by undifferentiated leukemic blasts. Recent advances in the capacity to sequence bulk tumor population as well as at a single-cell level has provided significant insight into the stepwise process of transformation to acute myeloid leukemia. Using models of progression in the context of germ line predisposition (trisomy 21, GATA2 deficiency, and SAMD9/9L syndrome), premalignant states (clonal hematopoiesis and clonal cytopenia of unknown significance), and myelodysplastic syndrome, we review the mechanisms of progression focusing on the hierarchy of clonal mutation and potential roles of transcription factor alterations, splicing factor mutations, and the bone marrow environment in progression to acute myeloid leukemia. Despite major advances in our understanding, preventing the progression of these disorders or treating them at the acute leukemia phase remains a major area of unmet medical need.

A novel GATA2 distal enhancer mutation results in MonoMAC syndrome in 2 second cousins

Mutations in the transcription factor GATA2 can cause MonoMAC syndrome, a GATA2 deficiency disease characterized by several findings, including disseminated nontuberculous mycobacterial infections, severe deficiencies of monocytes, natural killer cells, and B lymphocytes, and myelodysplastic syndrome. GATA2 mutations are found in ∼90% of patients with a GATA2 deficiency phenotype and are largely missense mutations in the conserved second zinc-finger domain. Mutations in an intron 5 regulatory enhancer element are also well described in GATA2 deficiency. Here, we present a multigeneration kindred with the clinical features of GATA2 deficiency but lacking an apparent GATA2 mutation. Whole genome sequencing revealed a unique adenine-to-thymine variant in the GATA2 -110 enhancer 116,855 bp upstream of the GATA2 ATG start site. The mutation creates a new E-box consensus in position with an existing GATA-box to generate a new hematopoietic regulatory composite element. The mutation segregates with the disease in several generations of the family. Cell type-specific allelic imbalance of GATA2 expression was observed in the bone marrow of a patient with higher expression from the mutant-linked allele. Allele-specific overexpression of GATA2 was observed in CRISPR/Cas9-modified HL-60 cells and in luciferase assays with the enhancer mutation. This study demonstrates overexpression of GATA2 resulting from a single nucleotide change in an upstream enhancer element in patients with MonoMAC syndrome. Patients in this study were enrolled in the National Institute of Allergy and Infectious Diseases clinical trial and the National Cancer Institute clinical trial (both trials were registered at www.clinicaltrials.gov as #NCT01905826 and #NCT01861106, respectively).

GATA 2 Deficiency: Focus on Immune System Impairment

GATA2 deficiency is a disease with a broad spectrum of clinical presentation, ranging from lymphedema, deafness, pulmonary dysfunction to miscarriage and urogenital anomalies, but it is mainly recognized as an immune system and bone marrow disorder. It is caused by various heterozygous mutations in the GATA2 gene, encoding for a zinc finger transcription factor with a key role for the development and maintenance of a pool of hematopoietic stem cells; notably, most of these mutations arise de novo. Patients carrying a mutated allele usually develop a loss of some cell populations, such as B-cell, dendritic cell, natural killer cell, and monocytes, and are predisposed to disseminated human papilloma virus and mycobacterial infections. Also, these patients have a predisposition to myeloid neoplasms, including myelodysplastic syndromes, myeloproliferative neoplasms, chronic myelomonocytic leukaemia. The age of symptoms onset can vary greatly even also within the same family, ranging from early childhood to late adulthood; incidence increases by age and most frequently clinical presentation is between the second and third decade of life. Currently, haematopoietic stem cell transplantation represents the only curative treatment, restoring both the hematopoietic and immune system function.