Congenital pancytopenia and absence of B lymphocytes in a neonate with a mutation in the ikaros gene

Goldman, Frederick D.; Gurel, Zafer; Al-Zubeidi, Duha; Fried, Ari J.; Icardi, Michael; Song, Chunhua; Dovat, Sinisa

doi:10.1002/pbc.23160

Cited by 78 publications

(52 citation statements)

References 38 publications

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“…21 The abnormal EMSA results and perinuclear localization for the N159A and H191R mutations were similar to the findings with the R162L, R162Q, H167R, and R184Q mutations. The Y210C mutation showed decreased but not absent DNA binding on an EMSA.…”

Section: Resultssupporting

confidence: 72%

“…21 The pathophysiological features and severity of the phenotype in this infant cannot be readily explained but may have been due to defects in functions of IKAROS that are unrelated to DNA binding or to additional genetic or nongenetic modifying factors. One of the more striking features of recently identified autosomal dominant genetic defects is the marked heterogeneity in phenotype caused by mutations in the same gene.…”

Section: Discussionmentioning

confidence: 96%

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Loss of B Cells in Patients with Heterozygous Mutations in IKAROS

et al. 2016

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BACKGROUND Common variable immunodeficiency (CVID) is characterized by late-onset hypogammaglobulinemia in the absence of predisposing factors. The genetic cause is unknown in the majority of cases, and less than 10% of patients have a family history of the disease. Most patients have normal numbers of B cells but lack plasma cells. METHODS We used whole-exome sequencing and array-based comparative genomic hybridization to evaluate a subset of patients with CVID and low B-cell numbers. Mutant proteins were analyzed for DNA binding with the use of an electrophoretic mobility-shift assay (EMSA) and confocal microscopy. Flow cytometry was used to analyze peripheral-blood lymphocytes and bone marrow aspirates. RESULTS Six different heterozygous mutations in IKZF1, the gene encoding the transcription factor IKAROS, were identified in 29 persons from six families. In two families, the mutation was a de novo event in the proband. All the mutations, four amino acid substitutions, an intragenic deletion, and a 4.7-Mb multigene deletion involved the DNA-binding domain of IKAROS. The proteins bearing missense mutations failed to bind target DNA sequences on EMSA and confocal microscopy; however, they did not inhibit the binding of wild-type IKAROS. Studies in family members showed progressive loss of B cells and serum immunoglobulins. Bone marrow aspirates in two patients had markedly decreased early B-cell precursors, but plasma cells were present. Acute lymphoblastic leukemia developed in 2 of the 29 patients. CONCLUSIONS Heterozygous mutations in the transcription factor IKAROS caused an autosomal dominant form of CVID that is associated with a striking decrease in B-cell numbers. (Funded by the National Institutes of Health and others.)

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Section: Resultssupporting

confidence: 72%

Section: Discussionmentioning

confidence: 96%

Loss of B Cells in Patients with Heterozygous Mutations in IKAROS

et al. 2016

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“…The deficiency of IKAROS, a zinc finger transcription factor essential during hematopoiesis, 75 has been reported to be associated with hematologic malignancies (reviewed in Wang et al 76 ) and also with congenital pancytopenia in humans. 77 It is known to impede B-and NK-cell development and is thus suspected to cause an immunodeficiency with antibody deficiency and cytopenia 3 (reviewed in John and Ward…”

Section: Bone Marrow Failure In Pidmentioning

confidence: 99%

Autoimmune and other cytopenias in primary immunodeficiencies: pathomechanisms, novel differential diagnoses, and treatment

Seidel

2014

Blood

128

140

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Autoimmunity and immune dysregulation may lead to cytopenia and represent key features of many primary immunodeficiencies (PIDs). Especially when cytopenia is the initial symptom of a PID, the order and depth of diagnostic steps have to be performed in accordance with both an immunologic and a hematologic approach and will help exclude disorders such as systemic lupus erythematosus, common variable immunodeficiency, and autoimmune lymphoproliferative syndromes, hemophagocytic disorders, lymphoproliferative diseases, and novel differential diagnoses such as MonoMac syndrome (GATA2 deficiency), CD27 deficiency, lipopolysaccharide-responsive beige-like anchor (LRBA) deficiency, activated PI3KD syndrome (APDS), X-linked immunodeficiency with magnesium defect (MAGT1 deficiency), and others. Immunosuppressive treatment often needs to be initiated urgently, which impedes further relevant immunologic laboratory analyses aimed at defining the underlying PID. Awareness of potentially involved disease spectra ranging from hematologic to rheumatologic and immunologic disorders is crucial for identifying a certain proportion of PID phenotypes and genotypes among descriptive diagnoses such as autoimmune hemolytic anemia, chronic immune thrombocytopenia, Evans syndrome, severe aplastic anemia/refractory cytopenia, and others. A synopsis of pathomechanisms, novel differential diagnoses, and advances in treatment options for cytopenias in PID is provided to facilitate multidisciplinary management and to bridge different approaches.

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“…[1][2][3][4] Ikaros knockout mice have severely impaired hematopoiesis, [5][6][7] whereas mice with the heterozygous loss of Ikaros develop T-cell leukemia. 8 In humans, impaired Ikaros activity due to the deletion or inactivating mutation of a single IKZF1 allele results in high-risk B-cell leukemia that is resistant to treatment.…”

Section: Introductionmentioning

confidence: 99%

Targeting casein kinase II restores Ikaros tumor suppressor activity and demonstrates therapeutic efficacy in high-risk leukemia

Song

Gowda

Pan

et al. 2015

Blood

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159

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• Ikaros controls cellular proliferation by repressing genes that regulate cell cycle progression and the PI3K pathway in leukemia.• CK2 inhibitor restores Ikaros tumor suppressor function in high-risk B-ALL with IKZF1 deletion and has a strong therapeutic effect in vivo.Ikaros (IKZF1) is a tumor suppressor that binds DNA and regulates expression of its target genes. The mechanism of Ikaros activity as a tumor suppressor and the regulation of Ikaros function in leukemia are unknown. Here, we demonstrate that Ikaros controls cellular proliferation by repressing expression of genes that promote cell cycle progression and the phosphatidylinositol-3 kinase (PI3K) pathway. We show that Ikaros function is impaired by the pro-oncogenic casein kinase II (CK2), and that CK2 is overexpressed in leukemia. CK2 inhibition restores Ikaros function as transcriptional repressor of cell cycle and PI3K pathway genes, resulting in an antileukemia effect. In high-risk leukemia where one IKZF1 allele has been deleted, CK2 inhibition restores the transcriptional repressor function of the remaining wild-type IKZF1 allele. CK2 inhibition demonstrated a potent therapeutic effect in a panel of patient-derived primary high-risk B-cell acute lymphoblastic leukemia xenografts as indicated by prolonged survival and a reduction of leukemia burden. We demonstrate the efficacy of a novel therapeutic approach for high-risk leukemia: restoration of Ikaros tumor suppressor activity via inhibition of CK2. These results provide a rationale for the use of CK2 inhibitors in clinical trials for high-risk leukemia, including cases with deletion of one IKZF1 allele. (Blood. 2015;126(15):1813-1822 Introduction Ikaros (IKZF1) activity is essential for normal hematopoiesis and immune development. [1][2][3][4] Ikaros knockout mice have severely impaired hematopoiesis, 5-7 whereas mice with the heterozygous loss of Ikaros develop T-cell leukemia. 8 In humans, impaired Ikaros activity due to the deletion or inactivating mutation of a single IKZF1 allele results in high-risk B-cell leukemia that is resistant to treatment.9-14 Ikaros regulates transcription of target genes via chromatin remodeling. [15][16][17] Ikaros activity is controlled through multiple mechanisms. Mouse studies suggest that the transcription of IKZF1 during normal hematopoiesis is regulated by a complex network. 18 However, Ikaros protein is expressed at high levels in most hematopoietic cells, and posttranslational modifications are hypothesized to play a critical role in regulating Ikaros activity. 19 Several groups have shown that phosphorylation, [19][20][21][22][23][24] sumoylation, 25 and ubiquitination 22 can regulate Ikaros function as a transcriptional repressor. However, the role of posttranslational modification in the regulation of Ikaros tumor suppressor activity in leukemia is unknown.Despite extensive global analyses of Ikaros DNA binding in normal murine hematopoietic cells, 26-28 the molecular mechanisms by which Ikaros exerts its tumor suppressor effects in human leukemia ...

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Congenital pancytopenia and absence of B lymphocytes in a neonate with a mutation in the ikaros gene

Cited by 78 publications

References 38 publications

Loss of B Cells in Patients with Heterozygous Mutations in IKAROS

Loss of B Cells in Patients with Heterozygous Mutations in IKAROS

Autoimmune and other cytopenias in primary immunodeficiencies: pathomechanisms, novel differential diagnoses, and treatment

Targeting casein kinase II restores Ikaros tumor suppressor activity and demonstrates therapeutic efficacy in high-risk leukemia

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