Project description:Inherited or sporadic mutations in the transcription factor GATA2 have been shown to be responsible for MonoMAC syndrome, a GATA2 deficiency disease characterized by a constellation of findings including disseminated non-tuberculous mycobacterial infections, severe deficiencies of monocytes, natural killer cells, and B-lymphocytes, and myelodysplastic syndrome. Mutations in the GATA2 gene are found in ~90% of patients with a GATA2 deficiency phenotype and are largely missense mutations in the conserved second zinc-finger domain or truncation mutations elsewhere in the coding sequence. Mutations in an intron 5 regulatory enhancer element are also well described in GATA2 deficiency. Here we present a large 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 116,855bp upstream of the GATA2 gene. 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 pattern in five generations of the family pedigree. Cell-type specific allelic imbalance of GATA2 expression is observed in a patient’s bone marrow with higher expression from the mutant-linked allele. Allele-specific overexpression of GATA2 is observed in CRISPR/Cas9-modified HL60 cultured cells and in luciferase assays with the enhancer mutation. This study demonstrates overexpression of GATA2 resulting from a single nucleotide change in an upstream regulatory enhancer element in patients with MonoMAC syndrome.
Project description:The majority (72%) of adolescents with myelodysplastic syndrome and monosomy 7 carry an underlying GATA2 deficiency. Nowadays, chemotherapy and allogenic hematopoietic stem cell transplantation (HSCT) are the only cure, pointing out the urgent need to develop reliable predictive tools. Familial cases carrying the same mutation in the GATA2 gene develop the disease at different age. The trigger of the disease is still unknown. Therefore, it is needed to understand the genetic mechanisms (mutations) and epigenetic mechanism, such as, DNA methylation, a cellular mechanism to control gene expression. Abnormal DNA methylation has been linked to several adverse outcomes, including human diseases. In this study, we deeply characterized 20 Spanish GATA2 deficient patients; study the presence of secondary mutations, clinical phenotype and DNA methylation. We have found that the most frequent secondary mutations are in STAG2 and ASXL1 genes, detected in 30% and 20% of the patients, respectively, a similar ratio has been described in a bigger cohort, showing that our 20-patient cohort is representative of the GATA2 deficiency scenario. For the first time, we found a specific hypermethylated signature in GATA2 patients, opening a novel point of view in the GATA2-patient diagnostic and facilitating the risk estimation of themselves. Furthermore, whether the methylation profiling is accurate enough, it will be useful to predict the onset of the disease progression.
Project description:To determine the difference of GATA2 related gene expression in blood cells. Gene expression of GATA2 deficiency comparing to a healthy person.
Project description:Background and Purpose: Constitutional GATA2 deficiency caused by heterozygous germline GATA2 mutation has a broad spectrum of clinical phenotypes including systemic infections, lymphedema, cytopenias, MDS and AML. A comprehensive profiling of transcriptome of hematopoiesis in GATA2 deficiency is currently lacking. Methods: We performed single-cell RNA sequencing of sorted bone marrow CD34+ hematopoietic stem and progenitor cells (HSPCs) from eight GATA2 deficiency patients, who had various well characterized GATA2 mutations and clinically manifest myelodysplasia. We characterized transcriptomes in lineages, computationally defined cells with chromosomal abnormalities, and described gene expression of these cells. Results: Mapping patients’ cells onto normal hematopoiesis, we observed preferred deficiency in lymphoid and myeloid progenitors, which also was evidenced in loss of heterogeneity in gene correlations. HSPCs in patients exhibited distinct gene expression pattern and gene coexpression pattern compared with its counterparts in healthy donors. Distinct lineages show different transcriptional profiles resulting from GATA2 mutations. HSCs in patients exhibited dysregulated genes in apoptosis, cell cycle and quiescence, and had increased expression of erythroid/megakaryocytic priming programs and decreased lymphoid priming programs. Thus, the prominent deficiency in myeloid/lymphoid lineages in GATA2 deficiency was partly due to expression of aberrant gene programs in HSCs prior to lineage commitment. We computationally defined cells with chromosomal abnormalities and described gene expression of these cells. DNA repair genes were downregulated in trisomy 8 cells, possibly rendering these cells vulnerable to second-hit somatic mutations and additional chromosomal abnormalities. Cells with complex cytogenetics had defects in multi-lineage differentiation and cell cycle. Conclusion: Germline GATA2 mutations modulate gene expression and change gene coexpression patterns. Distinct lineages show different transcriptional profiles resulting from GATA2 mutations. The prominent deficiency in myeloid/lymphoid lineages in GATA2 deficiency was partly due to expression of aberrant gene programs in HSCs prior to lineage commitment.
Project description:While certain human genetic variants are conspicuously loss-of-function, decoding the functional impact of many variants is challenging. Previously, we described a leukemia predisposition syndrome (GATA2-deficiency) patient with a germline GATA2 variant that inserts nine amino acids between the two zinc fingers (9aa-Ins). Here, we conducted mechanistic analyses using genomic technologies in Gata2 enhancer-mutant hematopoietic progenitor cells to reveal how the insertion impacts GATA2 function genome-wide. Despite being nuclear-localized, 9aa-Ins was severely defective, with activation more impaired than repression. Variation of the inter-zinc finger spacer length revealed that repression tolerated insertions that were detrimental to activation. GATA2 deficiency generated a hematopoiesis-disrupting signaling network in progenitor cells with reduced Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) signaling and elevated Interleukin-6 (IL-6) signaling. As insufficient GM-CSF signaling causes pulmonary alveolar proteinosis and excessive IL-6 signaling causes bone marrow failure, hallmark phenotypes of GATA2-deficiency patients, these results establish molecular mechanisms underlying GATA2-linked pathologies.
Project description:While certain human genetic variants are conspicuously loss-of-function, decoding the functional impact of many variants is challenging. Previously, we described a leukemia predisposition syndrome (GATA2-deficiency) patient with a germline GATA2 variant that inserts nine amino acids between the two zinc fingers (9aa-Ins). Here, we conducted mechanistic analyses using genomic technologies in Gata2 enhancer-mutant hematopoietic progenitor cells to reveal how the insertion impacts GATA2 function genome-wide. Despite being nuclear-localized, 9aa-Ins was severely defective, with activation more impaired than repression. Variation of the inter-zinc finger spacer length revealed that repression tolerated insertions that were detrimental to activation. GATA2 deficiency generated a hematopoiesis-disrupting signaling network in progenitor cells with reduced Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) signaling and elevated Interleukin-6 (IL-6) signaling. As insufficient GM-CSF signaling causes pulmonary alveolar proteinosis and excessive IL-6 signaling causes bone marrow failure, hallmark phenotypes of GATA2-deficiency patients, these results establish molecular mechanisms underlying GATA2-linked pathologies.