RESUMEN
Familial platelet disorder with associated myeloid malignancies (RUNX1-familial platelet disorder [RUNX1-FPD]) is caused by heterozygous pathogenic germline variants of RUNX1. In the present study, we evaluate the applicability of transactivation assays to investigate RUNX1 variants in different regions of the protein. We studied 11 variants to independently validate transactivation assays supporting variant classification following the ClinGen Myeloid Malignancies Variant Curation Expert Panel guidelines. Variant classification is key for the translation of genetic findings. We showed that new assays need to be developed to assess C-terminal RUNX1 variants. Two variants of uncertain significance (VUS) were reclassified to likely pathogenic. Additionally, our analyses supported the (likely) pathogenic classification of 2 other variants. We demonstrated functionality of 4 VUS, but reclassification to (likely) benign was challenging and suggested the need for reevaluating current classification guidelines. Finally, clinical utility of our assays was illustrated in the context of 7 families. Our data confirmed RUNX1-FPD suspicion in 3 families with RUNX1-FPD-specific family history, whereas for 3 variants identified in RUNX1-FPD-nonspecific families, no functional defect was detected. Applying functional assays to support RUNX1 variant classification can be essential for adequate care of index patients and their relatives at risk. It facilitates translation of genetic data into personalized medicine.
Asunto(s)
Trastornos de las Plaquetas Sanguíneas , Leucemia Mieloide Aguda , Trastornos de las Plaquetas Sanguíneas/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Células Germinativas , Humanos , Leucemia Mieloide Aguda/genética , Activación TranscripcionalRESUMEN
Septins play key roles in mammalian cell division and cytokinesis but have not previously been implicated in a germline human disorder. A male infant with severe neutropenia and progressive dysmyelopoiesis with tetraploid myeloid precursors was identified. No known genetic etiologies for neutropenia or bone marrow failure were found. However, next-generation sequencing of germline samples from the patient revealed a novel, de novo germline stop-loss mutation in the X-linked gene SEPT6 that resulted in reduced SEPT6 staining in bone marrow granulocyte precursors and megakaryocytes. Patient skin fibroblast-derived induced pluripotent stem cells (iPSCs) produced reduced myeloid colonies, particularly of the granulocyte lineage. CRISPR/Cas9 knock-in of the patient's mutation or complete knock-out of SEPT6 was not tolerated in non-patient-derived iPSCs or human myeloid cell lines, but SEPT6 knock-out was successful in an erythroid cell line and resulting clones revealed a propensity to multinucleation. In silico analysis predicts that the mutated protein hinders the dimerization of SEPT6 coiled-coils in both parallel and antiparallel arrangements, which could in turn impair filament formation. These data demonstrate a critical role for SEPT6 in chromosomal segregation in myeloid progenitors that can account for the unusual predisposition to aneuploidy and dysmyelopoiesis.
Asunto(s)
Enfermedades Genéticas Ligadas al Cromosoma X/genética , Mutación de Línea Germinal , Síndromes Mielodisplásicos/genética , Neutropenia/congénito , Septinas/genética , Línea Celular , Células Cultivadas , Enfermedades Genéticas Ligadas al Cromosoma X/complicaciones , Humanos , Recién Nacido , Masculino , Síndromes Mielodisplásicos/complicaciones , Neutropenia/complicaciones , Neutropenia/genética , TetraploidíaRESUMEN
To understand the mechanisms that mediate germline genetic leukemia predisposition, we studied the inherited ribosomopathy Shwachman-Diamond syndrome (SDS), a bone marrow failure disorder with high risk of myeloid malignancies at an early age. To define the mechanistic basis of clonal hematopoiesis in SDS, we investigate somatic mutations acquired by patients with SDS followed longitudinally. Here we report that multiple independent somatic hematopoietic clones arise early in life, most commonly harboring heterozygous mutations in EIF6 or TP53. We show that germline SBDS deficiency establishes a fitness constraint that drives selection of somatic clones via two distinct mechanisms with different clinical consequences. EIF6 inactivation mediates a compensatory pathway with limited leukemic potential by ameliorating the underlying SDS ribosome defect and enhancing clone fitness. TP53 mutations define a maladaptive pathway with enhanced leukemic potential by inactivating tumor suppressor checkpoints without correcting the ribosome defect. Subsequent development of leukemia was associated with acquisition of biallelic TP53 alterations. These results mechanistically link leukemia predisposition to germline genetic constraints on cellular fitness, and provide a rational framework for clinical surveillance strategies.
Asunto(s)
Hematopoyesis Clonal/genética , Hematopoyesis Clonal/fisiología , Síndrome de Shwachman-Diamond/genética , Síndrome de Shwachman-Diamond/metabolismo , Adolescente , Adulto , Enfermedades de la Médula Ósea/genética , Enfermedades de la Médula Ósea/metabolismo , Niño , Preescolar , Factores Eucarióticos de Iniciación/genética , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Mutación , Ribosomas/genética , Proteína p53 Supresora de Tumor/genética , Adulto JovenRESUMEN
BACKGROUND: Myelodysplastic syndromes (MDS) represent a group of clonal hematopoietic stem cell disorders that commonly progress to acute myeloid leukemia (AML). The diagnostics, prognostics, and treatment of adult MDS are established but do not directly translate to children and adolescents. Pediatric MDS is a rare disease, characterized by unique cytogenetics and histology compared with adult MDS, and often arises secondary to germline predisposition or cytotoxic exposures. Our objective was to highlight aspects of diagnosis/management that would benefit from further systematic review toward the development of clinical practice guidelines for pediatric MDS. PROCEDURE: The North American Pediatric Aplastic Anemia Consortium (NAPAAC) is composed of collaborative institutions with a strong interest in pediatric bone marrow failure syndromes and hematologic malignancies. The NAPAAC MDS working group developed a national survey distributed to 35 NAPAAC institutions to assess data on (1) clinical presentation of pediatric MDS, (2) diagnostic evaluation, (3) criteria for diagnosis, (4) supportive care and treatment decisions, and (5) role of hematopoietic stem cell transplantation (HSCT). RESULTS: Twenty-eight of 35 institutions returned the survey. Most centers agreed on a common diagnostic workup, though there was considerable variation regarding the criteria for diagnosis. Although there was consensus on supportive care, treatment strategies, including the role of cytoreduction and HSCT, varied across centers surveyed. CONCLUSIONS: There is lack of national consensus on diagnosis and treatment of pediatric MDS. This survey identified key aspects of MDS management that will warrant systematic review toward the goal of developing national clinical practice guidelines for pediatric MDS.
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Toma de Decisiones , Trasplante de Células Madre Hematopoyéticas/métodos , Síndromes Mielodisplásicos/diagnóstico , Síndromes Mielodisplásicos/terapia , Pautas de la Práctica en Medicina/estadística & datos numéricos , Anemia Aplásica/diagnóstico , Anemia Aplásica/terapia , Niño , Humanos , Pronóstico , Estudios Retrospectivos , Encuestas y Cuestionarios , Tasa de SupervivenciaRESUMEN
We report the outcomes of hematopoietic stem cell transplantation (HSCT) for 52 patients with Shwachman-Diamond syndrome (SDS) who underwent transplantation between 2000 and 2017. The median age at transplantation was 11 years, and the median duration of follow-up was 60 months. The indication for HSCT was bone marrow failure (BMF; cytopenia or aplastic anemia) in 39 patients and myelodysplasia (MDS)/acute myelogenous leukemia (AML) in 13 patients. The donor type was an HLA-matched sibling for 18 patients, an HLA-matched or mismatched relative for 6 patients, and an HLA-matched or mismatched unrelated donor for 28 patients. Preparative regimens for BMF were myeloablative in 13 patients and reduced intensity in 26. At the time of this report, 29 of the 39 patients with BMF were alive, and the 5-year overall survival was 72% (95% confidence interval, 57% to 86%). Graft failure and graft-versus-host disease were the predominant causes of death. Preparative regimens for patients with MDS/AML were myeloablative in 8 and reduced intensity in 5. At the time of this report, only 2 of 13 patients were alive (15%), with relapse the predominant cause of death. Survival after transplantation for SDS-related BMF is better compared with historical reports, but strategies are needed to overcome graft failure and graft-versus-host disease. For SDS- related MDS or AML, transplantation does not extend survival. Rigorous surveillance and novel treatments for leukemia are urgently needed.
Asunto(s)
Enfermedad Injerto contra Huésped , Trasplante de Células Madre Hematopoyéticas , Humanos , Síndrome de Shwachman-Diamond , Acondicionamiento Pretrasplante , Trasplante Homólogo , Donante no EmparentadoRESUMEN
Studies of genetic blood disorders have advanced our understanding of the intrinsic regulation of hematopoiesis. However, such genetic studies have only yielded limited insights into how interactions between hematopoietic cells and their microenvironment are regulated. Here, we describe two affected siblings with infantile myelofibrosis and myeloproliferation that share a common de novo mutation in the Rho GTPase CDC42 (Chr1:22417990:C>T, p.R186C) due to paternal germline mosaicism. Functional studies using human cells and flies demonstrate that this CDC42 mutant has altered activity and thereby disrupts interactions between hematopoietic progenitors and key tissue microenvironmental factors. These findings suggest that further investigation of this and other related disorders may provide insights into how hematopoietic cell-microenvironment interactions play a role in human health and can be disrupted in disease. In addition, we suggest that deregulation of CDC42 may underlie more common blood disorders, such as primary myelofibrosis.
Asunto(s)
Mutación/genética , Mielofibrosis Primaria/diagnóstico , Proteína de Unión al GTP cdc42/genética , Ciclo Celular , Microambiente Celular , Células HEK293 , Hematopoyesis/genética , Humanos , Lactante , Recién Nacido , Mielofibrosis Primaria/genética , Hermanos , Secuenciación del ExomaRESUMEN
Germline mutations in GATA2 are associated with an inherited predisposition to bone marrow failure (BMF), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). Hematopoietic stem cell transplantation (HSCT) remains the only curative therapy. However, patients may be at an increased risk for transplant-related toxicity (TRT) and transplant-related mortality (TRM) due to their underlying disease biology. We performed a retrospective case-control study of pediatric patients with BMF/MDS/AML with germline GATA2 mutations, comparing HSCT outcomes to randomly selected patients without germline GATA2 mutations and BMF/MDS (control A) and acute leukemia (control B). The 5-year overall and disease-free survival rates in the GATA2 cohort (65%, 51%) were similar to control A (58%, 49%) and B (45%, 43%) cohorts. In contrast, the 5-year event-free survival rate was significantly lower in the GATA2 cohort (7% ± 6%, 28% ± 10%, and 33% ± 8% for GATA2, A, and B, respectively), due to an increased number of unique TRTs. Specifically, neurologic toxicities occurred significantly more frequently in GATA2 patients than in the control groups, and post-HSCT thrombotic events occurred only in the GATA2 cohort. There was no difference in TRM, infections, or graft-versus-host disease across groups. The higher incidence of thrombotic and neurologic events specific to GATA2 patients warrants further investigation and has potential treatment ramifications.
Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Leucemia Mieloide Aguda , Síndromes Mielodisplásicos , Trastornos de Fallo de la Médula Ósea , Estudios de Casos y Controles , Niño , Factor de Transcripción GATA2/genética , Células Germinativas , Mutación de Línea Germinal , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/terapia , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/terapia , Estudios RetrospectivosRESUMEN
Shwachman-Diamond Syndrome (SDS) is a rare and clinically-heterogeneous bone marrow (BM) failure syndrome caused by mutations in the Shwachman-Bodian-Diamond Syndrome (SBDS) gene. Although SDS was described over 50 years ago, the molecular pathogenesis is poorly understood due, in part, to the rarity and heterogeneity of the affected hematopoietic progenitors. To address this, we used single cell RNA sequencing to profile scant hematopoietic stem and progenitor cells from SDS patients. We generated a single cell map of early lineage commitment and found that SDS hematopoiesis was left-shifted with selective loss of granulocyte-monocyte progenitors. Transcriptional targets of transforming growth factor-beta (TGFß) were dysregulated in SDS hematopoietic stem cells and multipotent progenitors, but not in lineage-committed progenitors. TGFß inhibitors (AVID200 and SD208) increased hematopoietic colony formation of SDS patient BM. Finally, TGFß3 and other TGFß pathway members were elevated in SDS patient blood plasma. These data establish the TGFß pathway as a novel candidate biomarker and therapeutic target in SDS and translate insights from single cell biology into a potential therapy.
Asunto(s)
Médula Ósea/fisiopatología , Células Madre Hematopoyéticas/patología , Síndrome de Shwachman-Diamond/fisiopatología , Factor de Crecimiento Transformador beta1/metabolismo , Adolescente , Adulto , Antígenos CD34/metabolismo , Diferenciación Celular , Linaje de la Célula , Niño , Granulocitos/citología , Hematopoyesis , Humanos , Inflamación , Monocitos/citología , Mutación , Fosforilación , Análisis de Secuencia de ARN , Transducción de Señal , Factor de Crecimiento Transformador beta/metabolismo , Adulto JovenRESUMEN
The development and function of stem and progenitor cells that produce blood cells are vital in physiology. GATA-binding protein 2 (GATA2) mutations cause GATA-2 deficiency syndrome involving immunodeficiency, myelodysplastic syndrome, and acute myeloid leukemia. GATA-2 physiological activities necessitate that it be strictly regulated, and cell type-specific enhancers fulfill this role. The +9.5 intronic enhancer harbors multiple conserved cis-elements, and germline mutations of these cis-elements are pathogenic in humans. Since mechanisms underlying how GATA2 enhancer disease mutations impact hematopoiesis and pathology are unclear, we generated mouse models of the enhancer mutations. While a multi-motif mutant was embryonically lethal, a single-nucleotide Ets motif mutant was viable, and steady-state hematopoiesis was normal. However, the Ets motif mutation abrogated stem/progenitor cell regeneration following stress. These results reveal a new mechanism in human genetics, in which a disease predisposition mutation inactivates enhancer regenerative activity, while sparing developmental activity. Mutational sensitization to stress that instigates hematopoietic failure constitutes a paradigm for GATA-2 deficiency syndrome and other contexts of GATA-2-dependent pathogenesis.
Asunto(s)
Elementos de Facilitación Genéticos , Deficiencia GATA2 , Factor de Transcripción GATA2 , Mutación de Línea Germinal , Hematopoyesis/genética , Motivos de Nucleótidos , Regeneración/genética , Animales , Deficiencia GATA2/genética , Deficiencia GATA2/metabolismo , Factor de Transcripción GATA2/genética , Factor de Transcripción GATA2/metabolismo , Humanos , Ratones , Ratones MutantesRESUMEN
The Notch signaling pathway contributes to the pathogenesis of a wide spectrum of human cancers, including hematopoietic malignancies. Its functions are highly dependent on the specific cellular context. Gain-of-function NOTCH1 mutations are prevalent in human T-cell leukemia, while loss of Notch signaling is reported in myeloid leukemias. Here, we report a novel oncogenic function of Notch signaling in oncogenic Kras-induced myeloproliferative neoplasm (MPN). We find that downregulation of Notch signaling in hematopoietic cells via DNMAML expression or Pofut1 deletion significantly blocks MPN development in KrasG12D mice in a cell-autonomous manner. Further mechanistic studies indicate that inhibition of Notch signaling upregulates Dusp1, a dual phosphatase that inactivates p-ERK, and downregulates cytokine-evoked ERK activation in KrasG12D cells. Moreover, mitochondrial metabolism is greatly enhanced in KrasG12D cells but significantly reprogrammed by DNMAML close to that in control cells. Consequently, cell proliferation and expanded myeloid compartment in KrasG12D mice are significantly reduced. Consistent with these findings, combined inhibition of the MEK/ERK pathway and mitochondrial oxidative phosphorylation effectively inhibited the growth of human and mouse leukemia cells in vitro. Our study provides a strong rational to target both ERK signaling and aberrant metabolism in oncogenic Ras-driven myeloid leukemia.
Asunto(s)
Regulación hacia Abajo/genética , Leucemia Mieloide/genética , Sistema de Señalización de MAP Quinasas/genética , Trastornos Mieloproliferativos/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Receptores Notch/genética , Transducción de Señal/genética , Animales , Proliferación Celular/genética , Citocinas/genética , Fosfatasa 1 de Especificidad Dual/genética , Ratones , Ratones Endogámicos C57BL , Mitocondrias/genética , Mutación/genética , Fosforilación Oxidativa , Regulación hacia Arriba/genéticaRESUMEN
Unlike primary myelofibrosis (PMF) in adults, myelofibrosis in children is rare. Congenital (inherited) forms of myelofibrosis (cMF) have been described, but the underlying genetic mechanisms remain elusive. Here we describe 4 families with autosomal recessive inherited macrothrombocytopenia with focal myelofibrosis due to germ line loss-of-function mutations in the megakaryocyte-specific immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing receptor G6b-B (G6b, C6orf25, or MPIG6B). Patients presented with a mild-to-moderate bleeding diathesis, macrothrombocytopenia, anemia, leukocytosis and atypical megakaryocytes associated with a distinctive, focal, perimegakaryocytic pattern of bone marrow fibrosis. In addition to identifying the responsible gene, the description of G6b-B as the mutated protein potentially implicates aberrant G6b-B megakaryocytic signaling and activation in the pathogenesis of myelofibrosis. Targeted insertion of human G6b in mice rescued the knockout phenotype and a copy number effect of human G6b-B expression was observed. Homozygous knockin mice expressed 25% of human G6b-B and exhibited a marginal reduction in platelet count and mild alterations in platelet function; these phenotypes were more severe in heterozygous mice that expressed only 12% of human G6b-B. This study establishes G6b-B as a critical regulator of platelet homeostasis in humans and mice. In addition, the humanized G6b mouse will provide an invaluable tool for further investigating the physiological functions of human G6b-B as well as testing the efficacy of drugs targeting this receptor.
Asunto(s)
Mutación con Pérdida de Función , Mielofibrosis Primaria/congénito , Receptores Inmunológicos/genética , Trombocitopenia/congénito , Adolescente , Adulto , Animales , Plaquetas/metabolismo , Plaquetas/patología , Niño , Preescolar , Femenino , Técnicas de Sustitución del Gen , Humanos , Lactante , Masculino , Megacariocitos/metabolismo , Megacariocitos/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Linaje , Mielofibrosis Primaria/genética , Mielofibrosis Primaria/patología , Trombocitopenia/genética , Trombocitopenia/patología , Adulto JovenRESUMEN
Patients with GATA2 haploinsufficiency have a significant predisposition to developing cytopenias, unique infectious manifestations, and myelodysplastic syndrome/acute myeloid leukemia (MDS/AML). We report a unique case of a patient who presented with B-cell acute lymphoblastic leukemia (B-ALL) and was subsequently diagnosed with monocytopenia and mycobacterium avium complex (MonoMAC) syndrome/GATA2 haploinsufficiency. The development of MDS/AML in patients with GATA2 haploinsufficiency is well described, however, the development of ALL has not been reported in the literature. ALL may be associated with GATA2 haploinsufficiency. Clinicians should be attuned to the features of the MonoMAC syndrome in patients with ALL that would prompt additional testing and alter treatment.
Asunto(s)
Factor de Transcripción GATA2/genética , Haploinsuficiencia/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Niño , Femenino , HumanosRESUMEN
Myeloproliferative neoplasms (MPN) are a group of clonal hematopoietic stem cell disorders characterized by aberrant proliferation of one or more myeloid lineages often with increased immature cells in the peripheral blood. The three classical BCR-ABL-negative MPNs are: 1) polycythemia vera (PV), 2) essential thrombocythemia (ET), and 3) primary myelofibrosis (PMF), which are typically disorders of older adults and are exceedingly rare in children. The diagnostic criteria for MPNs remain largely defined by clinical, laboratory and histopathology assessments in adults, but they have been applied to the pediatric population. The discovery of the JAK2 V617F mutation, and more recently, MPL and CALR mutations, are major landmarks in the understanding of MPNs. Nevertheless, they rarely occur in children, posing a significant diagnostic challenge given the lack of an objective, clonal marker. Therefore, in pediatric patients, the diagnosis must rely heavily on clinical and laboratory factors, and exclusion of secondary disorders to make an accurate diagnosis of MPN. This review focuses on the clinical presentation, diagnostic work up, differential diagnosis, treatment and prognosis of the classical BCR-ABL-negative MPNs (PV, ET and PMF) in children and highlights key differences to the adult diseases. Particular attention will be given to pediatric PMF, as it is the only disorder of this group that is observed in infants and young children, and in many ways appears to be a unique entity compared to adult PMF.
RESUMEN
Mutations in the PARN gene (encoding poly(A)-specific ribonuclease) cause telomere diseases including familial idiopathic pulmonary fibrosis (IPF) and dyskeratosis congenita, but how PARN deficiency impairs telomere maintenance is unclear. Here, using somatic cells and induced pluripotent stem cells (iPSCs) from patients with dyskeratosis congenita with PARN mutations, we show that PARN is required for the 3'-end maturation of the telomerase RNA component (TERC). Patient-derived cells as well as immortalized cells in which PARN is disrupted show decreased levels of TERC. Deep sequencing of TERC RNA 3' termini shows that PARN is required for removal of post-transcriptionally acquired oligo(A) tails that target nuclear RNAs for degradation. Diminished TERC levels and the increased proportion of oligo(A) forms of TERC are normalized by restoring PARN, which is limiting for TERC maturation in cells. Our results demonstrate a new role for PARN in the biogenesis of TERC and provide a mechanism linking PARN mutations to telomere diseases.
Asunto(s)
Regiones no Traducidas 3'/genética , Disqueratosis Congénita/genética , Exorribonucleasas/genética , Exorribonucleasas/metabolismo , Mutación/genética , ARN/genética , Telomerasa/genética , Telómero/genética , Células Cultivadas , Femenino , Fibroblastos/citología , Fibroblastos/metabolismo , Humanos , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Masculino , LinajeRESUMEN
The congenital sideroblastic anemias (CSAs) are relatively uncommon diseases characterized by defects in mitochondrial heme synthesis, iron-sulfur (Fe-S) cluster biogenesis, or protein synthesis. Here we demonstrate that mutations in HSPA9, a mitochondrial HSP70 homolog located in the chromosome 5q deletion syndrome 5q33 critical deletion interval and involved in mitochondrial Fe-S biogenesis, result in CSA inherited as an autosomal recessive trait. In a fraction of patients with just 1 severe loss-of-function allele, expression of the clinical phenotype is associated with a common coding single nucleotide polymorphism in trans that correlates with reduced messenger RNA expression and results in a pseudodominant pattern of inheritance.
Asunto(s)
Anemia Sideroblástica/genética , Enfermedades Genéticas Ligadas al Cromosoma X/genética , Proteínas HSP70 de Choque Térmico/genética , Proteínas Mitocondriales/genética , Adulto , Anciano , Secuencia de Bases , Análisis Mutacional de ADN , Femenino , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Mutación , Análisis de Secuencia por Matrices de Oligonucleótidos , Linaje , Polimorfismo de Nucleótido Simple , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Adulto JovenRESUMEN
We report germline missense mutations in ETV6 segregating with the dominant transmission of thrombocytopenia and hematologic malignancy in three unrelated kindreds, defining a new hereditary syndrome featuring thrombocytopenia with susceptibility to diverse hematologic neoplasms. Two variants, p.Arg369Gln and p.Arg399Cys, reside in the highly conserved ETS DNA-binding domain. The third variant, p.Pro214Leu, lies within the internal linker domain, which regulates DNA binding. These three amino acid sites correspond to hotspots for recurrent somatic mutation in malignancies. Functional studies show that the mutations abrogate DNA binding, alter subcellular localization, decrease transcriptional repression in a dominant-negative fashion and impair hematopoiesis. These familial genetic studies identify a central role for ETV6 in hematopoiesis and malignant transformation. The identification of germline predisposition to cytopenias and cancer informs the diagnosis and medical management of at-risk individuals.
Asunto(s)
Neoplasias Hematológicas/genética , Proteínas Proto-Oncogénicas c-ets/genética , Proteínas Represoras/genética , Trombocitopenia/genética , Proliferación Celular , Exones/genética , Femenino , Genes Reporteros , Mutación de Línea Germinal , Células HeLa , Humanos , Masculino , Modelos Moleculares , Datos de Secuencia Molecular , Mutación Missense , Linaje , Estructura Terciaria de Proteína , Proteínas Recombinantes , Análisis de Secuencia de ARN , Proteína ETS de Variante de Translocación 6RESUMEN
Pediatric acquired aplastic anemia (AA) is a bone marrow disorder that is difficult to distinguish from inherited bone marrow failure syndromes and hypocellular refractory cytopenia of childhood (RCC). Historically, patients with hypocellular RCC have been given the diagnosis of AA. To assess the clinical and histologic distinction between RCC and AA, we performed a retrospective analysis of 149 patients previously diagnosed with AA between 1976 and 2010. We evaluated event free survival (EFS), overall survival (OS), response rates to immunosuppressive therapy, treatment-related toxicities and clonal evolution. The 5-year EFS and OS were 50.8% ± 5.5% and 73.1% ± 4.7%, respectively. Patients with very severe AA had worse OS compared to patients with severe and moderately severe AA. Seventy-two patients had diagnostic pathology specimens available for review. Three pediatric hematopathologists reviewed and reclassified these specimens as AA, RCC or Other based on 2008 WHO Criteria. The concordance between pathologists in the diagnosis of AA or RCC was modest. RCC was associated with a trend toward improved OS and EFS and was not prognostic of immunosuppression therapy treatment failure. There was a low rate of clonal evolution exclusively associated with moderately severe AA. Our findings indicate that a diagnosis of RCC is difficult to establish with certainty and does not predict outcomes, calling into question the reproducibility and clinical significance of the RCC classification and warranting further studies.
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Anemia Aplásica/diagnóstico , Médula Ósea/patología , Inmunosupresores/uso terapéutico , Síndromes Mielodisplásicos/diagnóstico , Anemia Aplásica/tratamiento farmacológico , Anemia Aplásica/mortalidad , Niño , Evolución Clonal , Diagnóstico Diferencial , Femenino , Humanos , Inmunosupresores/administración & dosificación , Inmunosupresores/efectos adversos , Masculino , Registros Médicos , Síndromes Mielodisplásicos/tratamiento farmacológico , Síndromes Mielodisplásicos/mortalidad , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
Accurate and timely diagnosis of inherited bone marrow failure and inherited myelodysplastic syndromes is essential to guide clinical management. Distinguishing inherited from acquired bone marrow failure/myelodysplastic syndrome poses a significant clinical challenge. At present, diagnostic genetic testing for inherited bone marrow failure/myelodysplastic syndrome is performed gene-by-gene, guided by clinical and laboratory evaluation. We hypothesized that standard clinically-directed genetic testing misses patients with cryptic or atypical presentations of inherited bone marrow failure/myelodysplastic syndrome. In order to screen simultaneously for mutations of all classes in bone marrow failure/myelodysplastic syndrome genes, we developed and validated a panel of 85 genes for targeted capture and multiplexed massively parallel sequencing. In patients with clinical diagnoses of Fanconi anemia, genomic analysis resolved subtype assignment, including those of patients with inconclusive complementation test results. Eight out of 71 patients with idiopathic bone marrow failure or myelodysplastic syndrome were found to harbor damaging germline mutations in GATA2, RUNX1, DKC1, or LIG4. All 8 of these patients lacked classical clinical stigmata or laboratory findings of these syndromes and only 4 had a family history suggestive of inherited disease. These results reflect the extensive genetic heterogeneity and phenotypic complexity of bone marrow failure/myelodysplastic syndrome phenotypes. This study supports the integration of broad unbiased genetic screening into the diagnostic workup of children and young adults with bone marrow failure and myelodysplastic syndromes.
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Biomarcadores de Tumor/genética , Neoplasias de la Médula Ósea/diagnóstico , Neoplasias de la Médula Ósea/genética , Genómica/métodos , Mutación/genética , Síndromes Mielodisplásicos/diagnóstico , Síndromes Mielodisplásicos/genética , Adolescente , Adulto , Anciano , Neoplasias de la Médula Ósea/clasificación , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Síndromes Mielodisplásicos/clasificación , Fenotipo , Pronóstico , Adulto JovenRESUMEN
Myeloid sarcomas are extramedullary accumulations of immature myeloid cells that may present with or without evidence of pathologic involvement of the bone marrow or peripheral blood, and often coincide with or precede a diagnosis of acute myeloid leukemia (AML). A dearth of experimental models has hampered the study of myeloid sarcomas and led us to establish a new system in which tumor induction can be evaluated in an easily accessible non-hematopoietic tissue compartment. Using ex-vivo transduction of oncogenic Kras(G12V) into p16/p19(-/-) bone marrow cells, we generated transplantable leukemia-initiating cells that rapidly induced tumor formation in the skeletal muscle of immunocompromised NOD.SCID mice. In this model, murine histiocytic sarcomas, equivalent to human myeloid sarcomas, emerged at the injection site 30-50 days after cell implantation and consisted of tightly packed monotypic cells that were CD48+, CD47+ and Mac1+, with low or absent expression of other hematopoietic lineage markers. Tumor cells also infiltrated the bone marrow, spleen and other non-hematopoietic organs of tumor-bearing animals, leading to systemic illness (leukemia) within two weeks of tumor detection. P16/p19(-/-); Kras(G12V) myeloid sarcomas were multi-clonal, with dominant clones selected during secondary transplantation. The systemic leukemic phenotypes exhibited by histiocytic sarcoma-bearing mice were nearly identical to those of animals in which leukemia was introduced by intravenous transplantation of the same donor cells. Moreover, murine histiocytic sarcoma could be similarly induced by intramuscular injection of MLL-AF9 leukemia cells. This study establishes a novel, transplantable model of murine histiocytic/myeloid sarcoma that recapitulates the natural progression of these malignancies to systemic disease and indicates a cell autonomous leukemogenic mechanism.
Asunto(s)
Sarcoma Histiocítico/patología , Músculo Esquelético/patología , Lesiones Precancerosas/patología , Animales , Médula Ósea/patología , Células Clonales , Inhibidor p16 de la Quinasa Dependiente de Ciclina/deficiencia , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , ADN de Neoplasias/genética , Sarcoma Histiocítico/genética , Humanos , Leucemia/genética , Leucemia/patología , Ratones , Ratones Endogámicos NOD , Ratones SCID , Mutación/genética , Trasplante de Neoplasias , Oncogenes/genética , Fenotipo , Lesiones Precancerosas/genética , Proteínas Proto-Oncogénicas p21(ras)/genéticaRESUMEN
Dyskeratosis congenita (DC) is a rare inherited bone marrow failure syndrome caused by mutations in seven genes involved in telomere biology, with approximately 50% of cases remaining genetically uncharacterized. We report a patient with classic DC carrying a compound heterozygous mutation in the CTC1 (conserved telomere maintenance component 1) gene, which has recently implicated in the pleiotropic syndrome Coats plus. This report confirms a molecular link between DC and Coats plus and expands the genotype-phenotype complexity observed in telomere-related genetic disorders.