RESUMO
We report 5 children with bone marrow failure (BMF) after primary varicella zoster virus (VZV) infection or VZV vaccination, highlighting the highly variable course. Two patients were treated with intravenous immunoglobulins; one had a slow hematologic recovery, and the other was rescued by allogeneic hematopoietic stem cell transplantation (HSCT). Of the 2 patients treated with immunosuppressive therapy with antithymocyte globulin and cyclosporine, one had a complete response, and the other was transplanted for nonresponse. One patient underwent a primary allograft. All patients are alive. This study demonstrated that VZV-associated BMF is a life-threatening disorder that often requires HSCT.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Infecção pelo Vírus da Varicela-Zoster , Humanos , Masculino , Feminino , Criança , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Pré-Escolar , Herpesvirus Humano 3 , Transtornos da Insuficiência da Medula Óssea/etiologia , Vacinação/efeitos adversos , Doenças da Medula Óssea/etiologia , Vacina contra Varicela/efeitos adversos , Adolescente , Imunoglobulinas Intravenosas/uso terapêutico , LactenteAssuntos
Anemia Aplástica , Soro Antilinfocitário , Ciclosporina , Imunossupressores , Humanos , Soro Antilinfocitário/uso terapêutico , Anemia Aplástica/tratamento farmacológico , Ciclosporina/uso terapêutico , Criança , Imunossupressores/uso terapêutico , Cavalos , Animais , Masculino , Coelhos , Feminino , Adolescente , Pré-Escolar , Resultado do Tratamento , Lactente , Estudos RetrospectivosRESUMO
Myelodysplastic/myeloproliferative diseases of childhood cause a relevant disease burden, and many of these diseases may have a fatal course. The use of next-generation sequencing (NGS) has led to the identification of novel genetic variants in patients with these diseases, advancing our understanding of the underlying pathophysiology. However, novel mutations can often only be interpreted as variants of unknown significance (VUS), hindering adequate diagnosis and the use of a targeted therapy. To improve variant interpretation and test targeted therapies in a preclinical setting, we are using a rapid zebrafish embryo model that allows functional evaluation of the novel variant and possible therapeutic approaches within days. Thereby, we accelerate the translation from genetic findings to treatment options. Here, we establish this workflow on a novel in-frame tandem duplication in NRAS (c.192_227dup; p.G75_E76insDS65_G75) identified by Sanger sequencing in a 2.5-year-old patient with an unclassifiable myelodysplastic/myeloproliferative neoplasm (MDS/MPN-U). We show that this variant results in a myeloproliferative phenotype in zebrafish embryos with expansion of immature myeloid cells in the caudal hematopoietic tissue, which can be reversed by MEK inhibition. Thus, we could reclassify the variant from likely pathogenic to pathogenic using the American College of Medical Genetics (ACMG) criteria.
Assuntos
GTP Fosfo-Hidrolases , Proteínas de Membrana , Doenças Mieloproliferativas-Mielodisplásicas , Peixe-Zebra , Animais , Pré-Escolar , Feminino , Humanos , Masculino , Duplicação Gênica , GTP Fosfo-Hidrolases/genética , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas de Membrana/genética , Doenças Mieloproliferativas-Mielodisplásicas/genética , Sequências de Repetição em Tandem , Peixe-Zebra/genéticaRESUMO
Lomustine is an oral chemotherapy drug commonly used in pediatric neuro-oncology. We report on a 15-year-old formerly healthy boy, who was erroneously prescribed lomustine instead of an antibiotic for tonsillitis. He subsequently suffered from prolonged bone marrow aplasia with secondary fever in neutropenia and ubiquitous bleeding. Bone marrow regeneration started approximately 7 weeks after lomustine intake. No other permanent organ damage has been detected thus far. Oral chemotherapeutic drugs should only be prescribed by experts and dispensed in the smallest possible pack size.
RESUMO
Juvenile myelomonocytic leukaemia (JMML) is characterized by gene variants that deregulate the RAS signalling pathway. Children with neurofibromatosis type 1 (NF-1) carry a defective NF1 allele in the germline and are predisposed to JMML, which presumably requires somatic inactivation of the NF1 wild-type allele. Here we examined the two-hit concept in leukaemic cells of 25 patients with JMML and NF-1. Ten patients with JMML/NF-1 exhibited a NF1 loss-of-function variant in combination with uniparental disomy of the 17q arm. Five had NF1 microdeletions combined with a pathogenic NF1 variant and nine carried two compound-heterozygous NF1 variants. We also examined 16 patients without clinical signs of NF-1 and no variation in the JMML-associated driver genes PTPN11, KRAS, NRAS or CBL (JMML-5neg) and identified eight patients with NF1 variants. Three patients had microdeletions combined with hemizygous NF1 variants, three had compound-heterozygous NF1 variants and two had heterozygous NF1 variants. In addition, we found a high incidence of secondary ASXL1 and/or SETBP1 variants in both groups. We conclude that the clinical diagnosis of JMML/NF-1 reliably indicates a NF1-driven JMML subtype, and that careful NF1 analysis should be included in the genetic workup of JMML even in the absence of clinical evidence of NF-1.
Assuntos
Leucemia Mielomonocítica Juvenil , Neurofibromatose 1 , Criança , Humanos , Leucemia Mielomonocítica Juvenil/genética , Neurofibromatose 1/genética , Mutação , Transdução de Sinais , Genes Supressores de TumorRESUMO
Monosomy 7 is the most common cytogenetic abnormality in pediatric myelodysplastic syndrome (MDS) and associated with a high risk of disease progression. However, in young children, spontaneous loss of monosomy 7 with concomitant hematologic recovery has been described, especially in the presence of germline mutations in SAMD9 and SAMD9L genes. Here, we report on our experience of close surveillance instead of upfront hematopoietic stem cell transplantation (HSCT) in seven patients diagnosed with SAMD9L syndrome and monosomy 7 at a median age of 0.6 years (range, 0.4-2.9). Within 14 months from diagnosis, three children experienced spontaneous hematological remission accompanied by a decrease in monosomy 7 clone size. Subclones with somatic SAMD9L mutations in cis were identified in five patients, three of whom attained hematological remission. Two patients acquired RUNX1 and EZH2 mutations during the observation period, of whom one progressed to myelodysplastic syndrome with excess of blasts (MDS-EB). Four patients underwent allogeneic HSCT at a median time of 26 months (range, 14-40) from diagnosis for MDSEB, necrotizing granulomatous lymphadenitis, persistent monosomy 7, and severe neutropenia. At last follow-up, six patients were alive, while one passed away due to transplant-related causes. These data confirm previous observations that monosomy 7 can be transient in young children with SAMD9L syndrome. However, they also indicate that delaying HSCT poses a substantial risk of severe infection and disease progression. Finally, surveillance of patients with SAMD9L syndrome and monosomy 7 is critical to define the evolving genetic landscape and to determine the appropriate timing of HSCT (clinicaltrials gov. Identifier: NCT00662090).
Assuntos
Deleção Cromossômica , Síndromes Mielodisplásicas , Humanos , Criança , Pré-Escolar , Lactente , Remissão Espontânea , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/terapia , Progressão da Doença , Fatores de Transcrição/genética , Monossomia , Cromossomos Humanos Par 7/genética , Peptídeos e Proteínas de Sinalização Intracelular/genéticaRESUMO
GATA2 deficiency is a heterogeneous, multisystem disorder associated with a high risk of developing myelodysplastic syndrome (MDS) and the progression to acute myeloid leukemia. The mechanisms underlying malignant transformation in GATA2 deficiency remain poorly understood, necessitating predictive markers to assess an individual's risk of progression and guide therapeutic decisions. In this study, we performed a systematic analysis of bone marrow biopsies from 57 pediatric MDS patients. Focusing on hematopoiesis and the hematopoietic niche, including its microenvironment, we used multiplex immunofluorescence combined with multispectral imaging, gene expression profiling, and multiplex RNA in situ hybridization. Patients with a GATA2 deficiency exhibited a dysregulated GATA2 transcriptional network. Disease progression (GATA2-EB, n = 6) was associated with increased GATA2 mRNA levels, restored expression of the GATA2 target EZH2, and increased H3K27me3. GATA2-EB was further characterized by the high expression of the anti-apoptotic protein BCL2, a feature absent in children with a GATA2 deficiency and refractory cytopenia of childhood (GATA2-RCC, n = 24) or other pediatric MDS subgroups (RCC, n = 17; MDS-EB, n = 10). The multispectral imaging analysis of additional BCL2 family members revealed significantly elevated Mediators of Apoptosis Combinatorial (MAC) scores in GATA2-EB patients. Taken together, our findings highlight the potential drivers of disease progression in GATA2 deficiency, particularly increased histone trimethylation and dysregulated apoptosis. Furthermore, upregulated BCL2 and EZH2 and increased MAC scores provide a strong rationale for the use of venetoclax and azacitidine in therapeutic regimens for GATA2-EB.
RESUMO
C-terminal variants in CDC42 encoding cell division control protein 42 homolog underlie neonatal-onset cytopenia, autoinflammation, rash, and hemophagocytic lymphohistiocytosis (NOCARH). Pyrin inflammasome hyperactivation has been shown to contribute to disease pathophysiology. However, mortality of NOCARH patients remains high despite inflammasome-focused treatments. Here, we demonstrate in four NOCARH patients from three families that cell-intrinsic activation of type I interferon (IFN) is a previously unrecognized driver of autoinflammation in NOCARH. Our data show that aberrant innate immune activation is caused by sensing of cytosolic nucleic acids released from mitochondria, which exhibit disturbances in integrity and dynamics due to CDC42 dysfunction. In one of our patients, treatment with the Janus kinase inhibitor ruxolitinib led to complete remission, indicating that inhibition of type I IFN signaling may have an important role in the management of autoinflammation in patients with NOCARH.
Assuntos
Interferon Tipo I , Linfo-Histiocitose Hemofagocítica , Humanos , Recém-Nascido , Proteína cdc42 de Ligação ao GTP , Inflamassomos/genética , Linfo-Histiocitose Hemofagocítica/etiologia , Nitrilas , SíndromeRESUMO
Myeloid/lymphoid neoplasms with eosinophilia (MLN-eos) are rare haematological neoplasms primarily affecting adults. The heterogeneous clinical picture and the rarity of the disease, especially in children, may delay an early diagnosis. MLN-eos are characterized by constitutive tyrosine kinase (TK) activity due to gene fusions. It is thus of importance to obtain a prompt genetic diagnosis to start a specific therapy. Here, we outline the clinical, genetic, and biochemical background of TK driven MLN-eos and report two extremely rare paediatric cases of MLN-eo, the used diagnostic methods, therapy and clinical outcomes. Our results demonstrate that, standard cytogenetic and molecular methods may not be sufficient to diagnose MLN-eo due to cytogenetically cryptic aberrations. We therefore recommend performing additional evaluation with fluorescence in-situ hybridization and molecular genetic methods (array-based comparative genomic hybridization and RNA sequencing) which will lead to the correct diagnosis. Following this diagnostic route we detected a TNIP1::PDGFRB and a PCM1::FGFR1 fusion in our patients. Thus, genetic diagnosis must be precise and quick in order to initiate adequate therapies with tyrosine kinase inhibitors or HSCT.
Assuntos
Eosinofilia , Transtornos Mieloproliferativos , Neoplasias , Adulto , Humanos , Criança , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Hibridização Genômica Comparativa , Transtornos Mieloproliferativos/genética , Transtornos Mieloproliferativos/tratamento farmacológico , Eosinofilia/genética , Proteínas de Fusão Oncogênica/genética , Proteínas de Ligação a DNA/genética , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genéticaRESUMO
Pearson syndrome (PS) is a rare fatal mitochondrial disorder caused by single large-scale mitochondrial DNA deletions (SLSMDs). Most patients present with anemia in infancy. Bone marrow cytology with vacuolization in erythroid and myeloid precursors and ring-sideroblasts guides to the correct diagnosis, which is established by detection of SLSMDs. Non hematological symptoms suggesting a mitochondrial disease are often lacking at initial presentation, thus PS is an important differential diagnosis in isolated hypogenerative anemia in infancy. Spontaneous resolution of anemia occurs in two-third of patients at the age of 1-3 years, while multisystem non-hematological complications such as failure to thrive, muscle hypotonia, exocrine pancreas insufficiency, renal tubulopathy and cardiac dysfunction develop during the clinical course. Some patients with PS experience a phenotypical change to Kearns-Sayre syndrome. In the absence of curative therapy, the prognosis of patients with PS is dismal. Most patients die of acute lactic acidosis and multi-organ failure in early childhood. There is a great need for the development of novel therapies to alter the natural history of patients with PS.
Assuntos
Anemia , Síndrome de Kearns-Sayre , Doenças Mitocondriais , Anemia/complicações , Anemia/genética , Pré-Escolar , Síndrome Congênita de Insuficiência da Medula Óssea , DNA Mitocondrial/genética , Humanos , Lactente , Síndrome de Kearns-Sayre/complicações , Síndrome de Kearns-Sayre/genética , Erros Inatos do Metabolismo Lipídico , Doenças Mitocondriais/genética , Doenças MuscularesRESUMO
Regulation of mitochondrial respiration and morphology is important for maintaining steady-state hematopoiesis, yet few studies have comparatively evaluated the effects of abnormal mitochondrial respiration and dynamics on blood-cell differentiation in isolation or combination. This study sought to explore these effects in mouse models with one or both of the following deficits: a large-scale deletion of mitochondrial DNA (ΔmtDNA), accumulated to varying extents, or knockout of the mitochondrial fission factor Drp1. Each deficit was found to independently provoke anemia but with clearly different manifestations. The former showed signs of aberrant respiration, analogous to Pearson syndrome, while the latter showed signs of abnormal mitochondrial dynamics and was associated with changes in the relative proportions of leukocyte lineages. Combining these deficits acted to amplify abnormal iron metabolism in erythropoiesis, exacerbating anemia in an additive manner. Our results indicate that mitochondrial respiration and dynamics play distinct roles in different sets of processes and cell lineages in hematopoietic differentiation.
Assuntos
Anemia , DNA Mitocondrial , Camundongos , Animais , DNA Mitocondrial/genética , Modelos Animais de Doenças , Anemia/genética , LeucócitosRESUMO
BACKGROUND: CBL syndrome is a RASopathy caused by heterozygous germline mutations of the Casitas B-lineage lymphoma (CBL) gene. It is characterized by heterogeneous clinical phenotype, including developmental delay, facial dysmorphisms, cardiovascular malformations and an increased risk of cancer development, particularly juvenile myelomonocytic leukemia (JMML). Although the clinical phenotype has been progressively defined in recent years, immunological manifestations have not been well elucidated to date. METHODS: We studied the genetic, immunological, coagulative, and clinical profile of a family with CBL syndrome that came to our observation after the diagnosis of JMML, with homozygous CBL mutation, in one of the members. RESULTS: Variant analysis revealed the co-occurrence of CBL heterozygous mutation (c.1141 T > C) and SH2B3 mutation (c.1697G > A) in two other members. Patients carrying both mutations showed an ALPS-like phenotype characterized by lymphoproliferation, cytopenia, increased double-negative T-cells, impaired Fas-mediated lymphocyte apoptosis, altered cell death in PBMC and low TRECs expression. A coagulative work-up was also performed and showed the presence of subclinical coagulative alterations in patients carrying both mutations. CONCLUSION: In the reported family, we described immune dysregulation, as part of the clinical spectrum of CBL mutation with the co-occurrence of SH2B3.
Assuntos
Leucemia Mielomonocítica Juvenil , Proteínas Proto-Oncogênicas c-cbl , Células Germinativas/metabolismo , Mutação em Linhagem Germinativa/genética , Humanos , Leucemia Mielomonocítica Juvenil/complicações , Leucemia Mielomonocítica Juvenil/genética , Leucócitos Mononucleares/metabolismo , Proteínas Proto-Oncogênicas c-cbl/genética , Proteínas Proto-Oncogênicas c-cbl/metabolismoRESUMO
Dyskeratosis congenita (DC) is a bone marrow failure syndrome with extrahematopoietic abnormalities. DC is a paradigmatic telomere biology disorder (TBD) caused by germline mutations in genes responsible for telomere maintenance including TERT. Cryptic TBD is a bone marrow failure syndrome due to premature telomere shortening but without additional symptoms, frequently clinically indistinguishable from severe aplastic anemia (SAA) or hypoplastic myelodysplastic syndrome. We present the complex diagnostic pathway in a boy with a rare germline p.Thr726Met TERT variant with previous reports of SAA association and compromised enzymatic function who presented with juvenile myelomonocytic leukemia, which is a rare myelodysplastic/myeloproliferative neoplasm of childhood.
Assuntos
Anemia Aplástica , Disceratose Congênita , Leucemia Mielomonocítica Juvenil , Telomerase , Anemia Aplástica/genética , Transtornos da Insuficiência da Medula Óssea , Disceratose Congênita/genética , Células Germinativas , Humanos , Leucemia Mielomonocítica Juvenil/complicações , Leucemia Mielomonocítica Juvenil/genética , Masculino , Mutação , Telomerase/genéticaRESUMO
We diagnosed a 13-month-old girl with severe neurological deficits and hyporegenerative macrocytic anemiawith Brown-Vialetto-Van Laere syndrome type 2 (BVVL 2), a rare disorder of the riboflavin transporter, caused by variants in the SLC52A2 gene. Bone marrow aspiration revealed hypoplastic erythropoiesis and vacuolization of myelocytes, proerythroblasts, and micromegakaryocytes. We suggest BVVL 2 as an important differential diagnosis in hyporegenerative macrocytic anemia as rapid diagnosis and initiation of therapy are crucial for the remedy of hematological and neurological impairment.
Assuntos
Anemia Macrocítica , Paralisia Bulbar Progressiva , Perda Auditiva Neurossensorial , Anemia Macrocítica/diagnóstico , Anemia Macrocítica/genética , Paralisia Bulbar Progressiva/etiologia , Paralisia Bulbar Progressiva/genética , Feminino , Perda Auditiva Neurossensorial/genética , Humanos , Lactente , RiboflavinaRESUMO
The congenital sideroblastic anemias (CSAs) are a heterogeneous group of inherited disorders of erythropoiesis characterized by pathologic deposits of iron in the mitochondria of developing erythroblasts. Mutations in the mitochondrial glycine carrier SLC25A38 cause the most common recessive form of CSA. Nonetheless, the disease is still rare, there being fewer than 70 reported families. Here we describe the clinical phenotype and genotypes of 31 individuals from 24 families, including 11 novel mutations. We also review the spectrum of reported mutations and genotypes associated with the disease, describe the unique localization of missense mutations in transmembrane domains and account for the presence of several alleles in different populations.
Assuntos
Anemia Sideroblástica/congênito , Genótipo , Proteínas de Transporte da Membrana Mitocondrial/genética , Mutação , Fenótipo , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , MasculinoRESUMO
GATA2 deficiency is a heterogeneous multi-system disorder characterized by a high risk of developing myelodysplastic syndrome (MDS) and myeloid leukemia. We analyzed the outcome of 65 patients reported to the registry of the European Working Group (EWOG) of MDS in childhood carrying a germline GATA2 mutation (GATA2mut) who had undergone hematopoietic stem cell transplantation (HSCT). At 5 years the probability of overall survival and disease-free survival (DFS) was 75% and 70%, respectively. Non-relapse mortality and relapse equally contributed to treatment failure. There was no evidence of increased incidence of graft-versus-host-disease or excessive rates of infections or organ toxicities. Advanced disease and monosomy 7 (-7) were associated with worse outcome. Patients with refractory cytopenia of childhood (RCC) and normal karyotype showed an excellent outcome (DFS 90%) compared to RCC and -7 (DFS 67%). Comparing outcome of GATA2mut with GATA2wt patients, there was no difference in DFS in patients with RCC and normal karyotype. The same was true for patients with -7 across morphological subtypes. We demonstrate that HSCT outcome is independent of GATA2 germline mutations in pediatric MDS suggesting the application of standard MDS algorithms and protocols. Our data support considering HSCT early in the course of GATA2 deficiency in young individuals.