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1.
Am J Med Genet A ; 194(8): e63627, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38613168

RESUMO

Casitas B-lineage lymphoma (CBL) encodes an adaptor protein with E3-ligase activity negatively controlling intracellular signaling downstream of receptor tyrosine kinases. Somatic CBL mutations play a driver role in a variety of cancers, particularly myeloid malignancies, whereas germline defects in the same gene underlie a RASopathy having clinical overlap with Noonan syndrome (NS) and predisposing to juvenile myelomonocytic leukemia and vasculitis. Other features of the disorder include cardiac defects, postnatal growth delay, cryptorchidism, facial dysmorphisms, and predisposition to develop autoimmune disorders. Here we report a novel CBL variant (c.1202G>T; p.Cys401Phe) occurring de novo in a subject with café-au-lait macules, feeding difficulties, mild dysmorphic features, psychomotor delay, autism spectrum disorder, thrombocytopenia, hepatosplenomegaly, and recurrent hypertransaminasemia. The identified variant affects an evolutionarily conserved residue located in the RING finger domain, a known mutational hot spot of both germline and somatic mutations. Functional studies documented enhanced EGF-induced ERK phosphorylation in transiently transfected COS1 cells. The present findings further support the association of pathogenic CBL variants with immunological and hematological manifestations in the context of a presentation with only minor findings reminiscent of NS or a clinically related RASopathy.


Assuntos
Mutação em Linhagem Germinativa , Proteínas Proto-Oncogênicas c-cbl , Humanos , Proteínas Proto-Oncogênicas c-cbl/genética , Mutação em Linhagem Germinativa/genética , Masculino , Síndrome de Noonan/genética , Síndrome de Noonan/patologia , Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/patologia , Transtorno do Espectro Autista/imunologia , Transtorno do Espectro Autista/sangue , Predisposição Genética para Doença , Pré-Escolar , Criança , Animais , Fenótipo , Células COS , Trombocitopenia/genética , Trombocitopenia/patologia
3.
Environ Sci Pollut Res Int ; 30(38): 89140-89152, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37442937

RESUMO

The state of Rio Grande do Norte, located in the Northeast region of Brazil, has areas of granites and pegmatites with minerals that have varying concentrations of uranium. Consequently, high concentrations of radon gas, a carcinogenic substance for humans, can occur. The present study aimed to assess the occurrence of cancer and its association with exposure to sources of natural radioactivity using geological and geophysical information in the aforementioned state. The spatial dependence of pulmonary, breast, stomach, leukemia, and skin cancer cases with the location of radioisotope sources were analyzed using geoprocessing tools. The geoprocessing analysis showed a differential pattern of uranium emission throughout the state, with the highest emission from areas with pegmatites outcrops. A spatial dependency of cancer cases was shown (Moran index: 0.43; p < 0.01). Moreover, a higher rate of natural radioactivity-cancer cases was associated with the high-intensity natural radioactivity areas: odds ratio:1.21 (95% CI 1.20; 1.23), following the same pattern when separately compared the different related types of cancer. These results highlight the importance of natural radioactivity as a public health problem in the Brazilian environmental scenario, confirming the need for further studies as the first toward understanding and implementing health management strategies mitigating the exposures, especially in areas of environmental risk.


Assuntos
Neoplasias , Radioatividade , Radônio , Urânio , Humanos , Brasil/epidemiologia
4.
Front Mol Neurosci ; 16: 1170061, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37324589

RESUMO

De novo CLTC mutations underlie a spectrum of early-onset neurodevelopmental phenotypes having developmental delay/intellectual disability (ID), epilepsy, and movement disorders (MD) as major clinical features. CLTC encodes the widely expressed heavy polypeptide of clathrin, a major component of the coated vesicles mediating endocytosis, intracellular trafficking, and synaptic vesicle recycling. The underlying pathogenic mechanism is largely unknown. Here, we assessed the functional impact of the recurrent c.2669C > T (p.P890L) substitution, which is associated with a relatively mild ID/MD phenotype. Primary fibroblasts endogenously expressing the mutated protein show reduced transferrin uptake compared to fibroblast lines obtained from three unrelated healthy donors, suggesting defective clathrin-mediated endocytosis. In vitro studies also reveal a block in cell cycle transition from G0/G1 to the S phase in patient's cells compared to control cells. To demonstrate the causative role of the p.P890L substitution, the pathogenic missense change was introduced at the orthologous position of the Caenorhabditis elegans gene, chc-1 (p.P892L), via CRISPR/Cas9. The resulting homozygous gene-edited strain displays resistance to aldicarb and hypersensitivity to PTZ, indicating defective release of acetylcholine and GABA by ventral cord motor neurons. Consistently, mutant animals show synaptic vesicle depletion at the sublateral nerve cords, and slightly defective dopamine signaling, highlighting a generalized deficit in synaptic transmission. This defective release of neurotransmitters is associated with their secondary accumulation at the presynaptic membrane. Automated analysis of C. elegans locomotion indicates that chc-1 mutants move slower than their isogenic controls and display defective synaptic plasticity. Phenotypic profiling of chc-1 (+/P892L) heterozygous animals and transgenic overexpression experiments document a mild dominant-negative behavior for the mutant allele. Finally, a more severe phenotype resembling that of chc-1 null mutants is observed in animals harboring the c.3146 T > C substitution (p.L1049P), homologs of the pathogenic c.3140 T > C (p.L1047P) change associated with a severe epileptic phenotype. Overall, our findings provide novel insights into disease mechanisms and genotype-phenotype correlations of CLTC-related disorders.

5.
Genes (Basel) ; 14(2)2023 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-36833246

RESUMO

De novo mutations affecting the G protein α o subunit (Gαo)-encoding gene (GNAO1) cause childhood-onset developmental delay, hyperkinetic movement disorders, and epilepsy. Recently, we established Caenorhabditis elegans as an informative experimental model for deciphering pathogenic mechanisms associated with GNAO1 defects and identifying new therapies. In this study, we generated two additional gene-edited strains that harbor pathogenic variants which affect residues Glu246 and Arg209-two mutational hotspots in Gαo. In line with previous findings, biallelic changes displayed a variable hypomorphic effect on Gαo-mediated signaling that led to the excessive release of neurotransmitters by different classes of neurons, which, in turn, caused hyperactive egg laying and locomotion. Of note, heterozygous variants showed a cell-specific dominant-negative behavior, which was strictly dependent on the affected residue. As with previously generated mutants (S47G and A221D), caffeine was effective in attenuating the hyperkinetic behavior of R209H and E246K animals, indicating that its efficacy is mutation-independent. Conversely, istradefylline, a selective adenosine A2A receptor antagonist, was effective in R209H animals but not in E246K worms, suggesting that caffeine acts through both adenosine receptor-dependent and receptor-independent mechanisms. Overall, our findings provide new insights into disease mechanisms and further support the potential efficacy of caffeine in controlling dyskinesia associated with pathogenic GNAO1 mutations.


Assuntos
Caenorhabditis elegans , Epilepsia , Animais , Cafeína , Mutação , Epilepsia/genética , Proteínas de Ligação ao GTP/genética
6.
J Allergy Clin Immunol ; 150(1): 223-228, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35157921

RESUMO

BACKGROUND: Pathogenic missense variants in cell division control protein 42 (CDC42) differentially affect protein function, causing a clinically wide phenotypic spectrum variably affecting neurodevelopment, hematopoiesis, and immune response. More recently, 3 variants at the C-terminus of CDC42 were proposed to similarly impact protein function and cause a novel autoinflammatory disorder. OBJECTIVES: We sought to clinically and functionally classify these variants to improve patient management. METHODS: Comparative analysis of the available clinical data and medical history of patients was performed. In vitro and in vivo studies were carried out to functionally characterize individual variants. RESULTS: Differently from what had previously been observed for the p.R186C change causing neonatal-onset cytopenia, autoinflammation, and recurrent hemophagocytic lymphohistiocytosis, p.C188Y and p.∗192Cext∗24 promoted accelerated protein degradation. Unprenylated CDC42C188Y did not behave as a membrane-bound protein, whereas the residual CDC42∗192Cext∗24 mutant replicated the CDC42R186C behavior, being targeted to the Golgi apparatus in a palmitoylation-dependent manner. Assessment of in vitro polarized migration and development in Caenorhabditis elegans documented a loss-of-function behavior of the p.C188Y and p.∗192Cext∗24 variants. Consistently, the 3 pathogenic variants were associated with different clinical presentations, with dysmorphisms, severity, and age of onset of cytopenia and extent of autoinflammation representing major differences. CONCLUSIONS: Pathogenic variants at the CDC42 C-terminus differently impact protein stability, localization, and function, and cause different diseases, with p.R186C specifically associated with neonatal-onset pancytopenia and severe autoinflammation/hemophagocytic lymphohistiocytosis requiring emapalumab and bone marrow transplantation, and p.C188Y and p.∗192Cext∗24 causing anakinra-sensitive autoinflammation.


Assuntos
Doenças do Sistema Imunitário , Linfo-Histiocitose Hemofagocítica , Proteína cdc42 de Ligação ao GTP , Hematopoese , Humanos , Recém-Nascido , Linfo-Histiocitose Hemofagocítica/genética , Mutação , Proteína cdc42 de Ligação ao GTP/genética
7.
Hum Mol Genet ; 31(6): 929-941, 2022 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-34622282

RESUMO

Dominant GNAO1 mutations cause an emerging group of childhood-onset neurological disorders characterized by developmental delay, intellectual disability, movement disorders, drug-resistant seizures and neurological deterioration. GNAO1 encodes the α-subunit of an inhibitory GTP/GDP-binding protein regulating ion channel activity and neurotransmitter release. The pathogenic mechanisms underlying GNAO1-related disorders remain largely elusive and there are no effective therapies. Here, we assessed the functional impact of two disease-causing variants associated with distinct clinical features, c.139A > G (p.S47G) and c.662C > A (p.A221D), using Caenorhabditis elegans as a model organism. The c.139A > G change was introduced into the orthologous position of the C. elegans gene via CRISPR/Cas9, whereas a knock-in strain carrying the p.A221D variant was already available. Like null mutants, homozygous knock-in animals showed increased egg laying and were hypersensitive to aldicarb, an inhibitor of acetylcholinesterase, suggesting excessive neurotransmitter release by different classes of motor neurons. Automated analysis of C. elegans locomotion indicated that goa-1 mutants move faster than control animals, with more frequent body bends and a higher reversal rate and display uncoordinated locomotion. Phenotypic profiling of heterozygous animals revealed a strong hypomorphic effect of both variants, with a partial dominant-negative activity for the p.A221D allele. Finally, caffeine was shown to rescue aberrant motor function in C. elegans harboring the goa-1 variants; this effect is mainly exerted through adenosine receptor antagonism. Overall, our findings establish a suitable platform for drug discovery, which may assist in accelerating the development of new therapies for this devastating condition, and highlight the potential role of caffeine in controlling GNAO1-related dyskinesia.


Assuntos
Proteínas de Caenorhabditis elegans , Discinesias , Acetilcolinesterase/metabolismo , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Cafeína/farmacologia , Avaliação Pré-Clínica de Medicamentos , Discinesias/tratamento farmacológico , Discinesias/genética , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/farmacologia , Proteínas de Ligação ao GTP/genética , Mutação , Neurotransmissores/metabolismo
8.
J Clin Endocrinol Metab ; 107(3): 668-684, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-34718610

RESUMO

CONTEXT: Genes causing familial forms of diabetes mellitus are only partially known. OBJECTIVE: We set out to identify the genetic cause of hyperglycemia in multigenerational families with an apparent autosomal dominant form of adult-onset diabetes not due to mutations in known monogenic diabetes genes. METHODS: Existing whole-exome sequencing (WES) data were used to identify exonic variants segregating with diabetes in 60 families from the United States and Italy. Functional studies were carried out in vitro (transduced MIN6-K8 cells) and in vivo (Caenorhabditis elegans) to assess the diabetogenic potential of 2 variants in the malate dehydrogenase 2 (MDH2) gene linked with hyperglycemia in 2 of the families. RESULTS: A very rare mutation (p.Arg52Cys) in MDH2 strongly segregated with hyperglycemia in 1 family from the United States. An infrequent MDH2 missense variant (p.Val160Met) also showed disease cosegregation in a family from Italy, although with reduced penetrance. In silico, both Arg52Cys and Val160Met were shown to affect MDH2 protein structure and function. In transfected HepG2 cells, both variants significantly increased MDH2 enzymatic activity, thereby decreasing the NAD+/NADH ratio-a change known to affect insulin signaling and secretion. Stable expression of human wild-type MDH2 in MIN6-K8 cell lines enhanced glucose- and GLP-1-stimulated insulin secretion. This effect was blunted by the Cys52 or Met160 substitutions. Nematodes carrying equivalent changes at the orthologous positions of the mdh-2 gene showed impaired glucose-stimulated insulin secretion. CONCLUSION: Our findings suggest a central role of MDH2 in human glucose homeostasis and indicate that gain of function variants in this gene may be involved in the etiology of familial forms of diabetes.


Assuntos
Glicemia/metabolismo , Hiperglicemia/genética , Malato Desidrogenase/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Animais Geneticamente Modificados , Glicemia/análise , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Estudos de Casos e Controles , Linhagem Celular Tumoral , Análise Mutacional de DNA , Feminino , Mutação com Ganho de Função , Humanos , Hiperglicemia/sangue , Insulina/análise , Insulina/metabolismo , Secreção de Insulina/genética , Ilhotas Pancreáticas , Malato Desidrogenase/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Modelos Animais , Cultura Primária de Células , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sequenciamento do Exoma
9.
J Med Chem ; 64(21): 15973-15990, 2021 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-34714648

RESUMO

We developed a new class of inhibitors of protein-protein interactions of the SHP2 phosphatase, which is pivotal in cell signaling and represents a central target in the therapy of cancer and rare diseases. Currently available SHP2 inhibitors target the catalytic site or an allosteric pocket but lack specificity or are ineffective for disease-associated SHP2 mutants. Considering that pathogenic lesions cause signaling hyperactivation due to increased levels of SHP2 association with cognate proteins, we developed peptide-based molecules with nanomolar affinity for the N-terminal Src homology domain of SHP2, good selectivity, stability to degradation, and an affinity for pathogenic variants of SHP2 that is 2-20 times higher than for the wild-type protein. The best peptide reverted the effects of a pathogenic variant (D61G) in zebrafish embryos. Our results provide a novel route for SHP2-targeted therapies and a tool for investigating the role of protein-protein interactions in the function of SHP2.


Assuntos
Oncogenes , Proteína Tirosina Fosfatase não Receptora Tipo 11/antagonistas & inibidores , Domínios de Homologia de src/efeitos dos fármacos , Animais , Sítios de Ligação , Mutação , Ligação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Transdução de Sinais , Peixe-Zebra/embriologia
10.
Clin Genet ; 100(5): 563-572, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34346503

RESUMO

Neurofibromatosis 1 (NF1) is a disorder characterized by variable expressivity caused by loss-of-function variants in NF1, encoding neurofibromin, a protein negatively controlling RAS signaling. We evaluated whether concurrent variation in proteins functionally linked to neurofibromin contribute to the variable expressivity of NF1. Parallel sequencing of a RASopathy gene panel in 138 individuals with molecularly confirmed clinical diagnosis of NF1 identified missense variants in PTPN11, encoding SHP2, a positive regulator of RAS signaling, in four subjects from three unrelated families. Three subjects were heterozygous for a gain-of-function variant and showed a severe expression of NF1 (developmental delay, multiple cerebral neoplasms and peculiar cortical MRI findings), and features resembling Noonan syndrome (a RASopathy caused by activating variants in PTPN11). Conversely, the fourth subject, who showed an attenuated presentation, carried a previously unreported PTPN11 variant that had a hypomorphic behavior in vitro. Our findings document that functionally relevant PTPN11 variants occur in a small but significant proportion of subjects with NF1 modulating disease presentation, suggesting a model in which the clinical expression of pathogenic NF1 variants is modified by concomitant dysregulation of protein(s) functionally linked to neurofibromin. We also suggest targeting of SHP2 function as an approach to treat evolutive complications of NF1.


Assuntos
Encéfalo/anormalidades , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética , Mutação , Neurofibromatose 1/diagnóstico , Neurofibromatose 1/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Adolescente , Criança , Análise Mutacional de DNA , Família , Feminino , Genes da Neurofibromatose 1 , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Modelos Moleculares , Mutação de Sentido Incorreto , Linhagem , Fenótipo , Conformação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 11/química , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Relação Estrutura-Atividade
11.
Sci Rep ; 11(1): 17133, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34429473

RESUMO

Chemosensory receptors play a crucial role in distinguishing the wide range of volatile/soluble molecules by binding them with high accuracy. Chemosensation is the main sensory modality in organisms lacking long-range sensory mechanisms like vision/hearing. Despite its low number of sensory neurons, the nematode Caenorhabditis elegans possesses several chemosensory receptors, allowing it to detect about as many odorants as mammals. Here, we show that C. elegans displays attraction towards urine samples of women with breast cancer, avoiding control ones. Behavioral assays on animals lacking AWC sensory neurons demonstrate the relevance of these neurons in sensing cancer odorants: calcium imaging on AWC increases the accuracy of the discrimination (97.22%). Also, chemotaxis assays on animals lacking GPCRs expressed in AWC allow to identify receptors involved in binding cancer metabolites, suggesting that an alteration of a few metabolites is sufficient for the cancer discriminating behavior of C. elegans, which may help identify a fundamental fingerprint of breast cancer.


Assuntos
Biomarcadores Tumorais/urina , Neoplasias da Mama/urina , Caenorhabditis elegans/fisiologia , Quimiotaxia , Animais , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Células Quimiorreceptoras/metabolismo , Células Quimiorreceptoras/fisiologia , Feminino , Humanos , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo
12.
Am J Hum Genet ; 107(3): 499-513, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32721402

RESUMO

Signal transduction through the RAF-MEK-ERK pathway, the first described mitogen-associated protein kinase (MAPK) cascade, mediates multiple cellular processes and participates in early and late developmental programs. Aberrant signaling through this cascade contributes to oncogenesis and underlies the RASopathies, a family of cancer-prone disorders. Here, we report that de novo missense variants in MAPK1, encoding the mitogen-activated protein kinase 1 (i.e., extracellular signal-regulated protein kinase 2, ERK2), cause a neurodevelopmental disease within the RASopathy phenotypic spectrum, reminiscent of Noonan syndrome in some subjects. Pathogenic variants promote increased phosphorylation of the kinase, which enhances translocation to the nucleus and boosts MAPK signaling in vitro and in vivo. Two variant classes are identified, one of which directly disrupts binding to MKP3, a dual-specificity protein phosphatase negatively regulating ERK function. Importantly, signal dysregulation driven by pathogenic MAPK1 variants is stimulus reliant and retains dependence on MEK activity. Our data support a model in which the identified pathogenic variants operate with counteracting effects on MAPK1 function by differentially impacting the ability of the kinase to interact with regulators and substrates, which likely explains the minor role of these variants as driver events contributing to oncogenesis. After nearly 20 years from the discovery of the first gene implicated in Noonan syndrome, PTPN11, the last tier of the MAPK cascade joins the group of genes mutated in RASopathies.


Assuntos
Carcinogênese/genética , Proteína Quinase 1 Ativada por Mitógeno/genética , Transtornos do Neurodesenvolvimento/genética , Síndrome de Noonan/genética , Pré-Escolar , Feminino , Humanos , Sistema de Sinalização das MAP Quinases/genética , Masculino , Mutação de Sentido Incorreto/genética , Transtornos do Neurodesenvolvimento/patologia , Síndrome de Noonan/fisiopatologia , Fenótipo , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Transdução de Sinais , Sequenciamento do Exoma , Proteínas ras/genética
13.
Hum Mutat ; 41(6): 1171-1182, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32112654

RESUMO

Germline PTPN11 mutations cause Noonan syndrome (NS), the most common disorder among RASopathies. PTPN11 encodes SHP2, a protein tyrosine-phosphatase controlling signaling through the RAS-MAPK and PI3K-AKT pathways. Generally, NS-causing PTPN11 mutations are missense changes destabilizing the inactive conformation of the protein or enhancing its binding to signaling partners. Here, we report on two PTPN11 variants resulting in the deletion or duplication of one of three adjacent glutamine residues (Gln255 -to-Gln257 ). While p.(Gln257dup) caused a typical NS phenotype in carriers of a first family, p.(Gln257del) had incomplete penetrance in a second family. Missense mutations involving Gln256 had previously been reported in NS. This poly-glutamine stretch is located on helix B of the PTP domain, a region involved in stabilizing SHP2 in its autoinhibited state. Molecular dynamics simulations predicted that changes affecting this motif perturb the SHP2's catalytically inactive conformation and/or substrate recognition. Biochemical data showed that duplication and deletion of Gln257 variably enhance SHP2's catalytic activity, while missense changes involving Gln256 affect substrate specificity. Expression of mutants in HEK293T cells documented their activating role on MAPK signaling, uncoupling catalytic activity and modulation of intracellular signaling. These findings further document the relevance of helix B in the regulation of SHP2's function.


Assuntos
Síndrome de Noonan/genética , Peptídeos/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Adolescente , Criança , Pré-Escolar , Feminino , Glutamina/genética , Células HEK293 , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Domínios Proteicos , Transdução de Sinais
14.
J Exp Med ; 216(12): 2778-2799, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31601675

RESUMO

Hemophagocytic lymphohistiocytosis (HLH) is characterized by immune dysregulation due to inadequate restraint of overactivated immune cells and is associated with a variable clinical spectrum having overlap with more common pathophysiologies. HLH is difficult to diagnose and can be part of inflammatory syndromes. Here, we identify a novel hematological/autoinflammatory condition (NOCARH syndrome) in four unrelated patients with superimposable features, including neonatal-onset cytopenia with dyshematopoiesis, autoinflammation, rash, and HLH. Patients shared the same de novo CDC42 mutation (Chr1:22417990C>T, p.R186C) and altered hematopoietic compartment, immune dysregulation, and inflammation. CDC42 mutations had been associated with syndromic neurodevelopmental disorders. In vitro and in vivo assays documented unique effects of p.R186C on CDC42 localization and function, correlating with the distinctiveness of the trait. Emapalumab was critical to the survival of one patient, who underwent successful bone marrow transplantation. Early recognition of the disorder and establishment of treatment followed by bone marrow transplant are important to survival.


Assuntos
Suscetibilidade a Doenças , Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfo-Histiocitose Hemofagocítica/genética , Fenótipo , Proteína cdc42 de Ligação ao GTP/genética , Proteína cdc42 de Ligação ao GTP/metabolismo , Alelos , Substituição de Aminoácidos , Animais , Sítios de Ligação , Linhagem Celular Tumoral , Criança , Feminino , Estudos de Associação Genética , Genótipo , Humanos , Lactente , Masculino , Camundongos , Modelos Moleculares , Conformação Molecular , Mutação , Ligação Proteica , Proteína cdc42 de Ligação ao GTP/química
15.
Hum Mutat ; 36(11): 1080-7, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26173643

RESUMO

The RASopathies constitute a family of autosomal-dominant disorders whose major features include facial dysmorphism, cardiac defects, reduced postnatal growth, variable cognitive deficits, ectodermal and skeletal anomalies, and susceptibility to certain malignancies. Noonan syndrome (NS), the commonest RASopathy, is genetically heterogeneous and caused by functional dysregulation of signal transducers and regulatory proteins with roles in the RAS/extracellular signal-regulated kinase (ERK) signal transduction pathway. Mutations in known disease genes account for approximately 80% of affected individuals. Here, we report that missense mutations altering Son of Sevenless, Drosophila, homolog 2 (SOS2), which encodes a RAS guanine nucleotide exchange factor, occur in a small percentage of subjects with NS. Four missense mutations were identified in five unrelated sporadic cases and families transmitting NS. Disease-causing mutations affected three conserved residues located in the Dbl homology (DH) domain, of which two are directly involved in the intramolecular binding network maintaining SOS2 in its autoinhibited conformation. All mutations were found to promote enhanced signaling from RAS to ERK. Similar to NS-causing SOS1 mutations, the phenotype associated with SOS2 defects is characterized by normal development and growth, as well as marked ectodermal involvement. Unlike SOS1 mutations, however, those in SOS2 are restricted to the DH domain.


Assuntos
Estudos de Associação Genética , Mutação , Síndrome de Noonan/genética , Domínios e Motivos de Interação entre Proteínas/genética , Proteínas Son Of Sevenless/genética , Adolescente , Adulto , Alelos , Substituição de Aminoácidos , Criança , Análise Mutacional de DNA , Exoma , Fácies , Feminino , Genótipo , Humanos , Masculino , Modelos Moleculares , Síndrome de Noonan/diagnóstico , Fenótipo , Conformação Proteica , Proteínas Son Of Sevenless/química , Adulto Jovem
16.
Hum Mutat ; 36(8): 787-96, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25952305

RESUMO

Noonan syndrome (NS) is a relatively common developmental disorder with a pleomorphic phenotype. Mutations causing NS alter genes encoding proteins involved in the RAS-MAPK pathway. We and others identified Casitas B-lineage lymphoma proto-oncogene (CBL), which encodes an E3-ubiquitin ligase acting as a tumor suppressor in myeloid malignancies, as a disease gene underlying a condition clinically related to NS. Here, we further explored the spectrum of germline CBL mutations and their associated phenotype. CBL mutation scanning performed on 349 affected subjects with features overlapping NS and no mutation in NS genes allowed the identification of five different variants with pathological significance. Among them, two splice-site changes, one in-frame deletion, and one missense mutation affected the RING domain and/or the adjacent linker region, overlapping cancer-associated defects. A novel nonsense mutation generating a v-Cbl-like protein able to enhance signal flow through RAS was also identified. Genotype-phenotype correlation analysis performed on available records indicated that germline CBL mutations cause a variable phenotype characterized by a relatively high frequency of neurological features, predisposition to juvenile myelomonocytic leukemia, and low prevalence of cardiac defects, reduced growth, and cryptorchidism. Finally, we excluded a major contribution of two additional members of the CBL family, CBLB and CBLC, to NS and related disorders.


Assuntos
Variação Genética , Mutação em Linhagem Germinativa , Proteínas Proto-Oncogênicas c-cbl/genética , Pré-Escolar , Feminino , Estudos de Associação Genética , Humanos , Masculino , Síndrome de Noonan/genética , Síndrome de Noonan/fisiopatologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-cbl/metabolismo
17.
Hum Mol Genet ; 23(16): 4315-27, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24705357

RESUMO

RASopathies, a family of disorders characterized by cardiac defects, defective growth, facial dysmorphism, variable cognitive deficits and predisposition to certain malignancies, are caused by constitutional dysregulation of RAS signalling predominantly through the RAF/MEK/ERK (MAPK) cascade. We report on two germline mutations (p.Gly39dup and p.Val55Met) in RRAS, a gene encoding a small monomeric GTPase controlling cell adhesion, spreading and migration, underlying a rare (2 subjects among 504 individuals analysed) and variable phenotype with features partially overlapping Noonan syndrome, the most common RASopathy. We also identified somatic RRAS mutations (p.Gly39dup and p.Gln87Leu) in 2 of 110 cases of non-syndromic juvenile myelomonocytic leukaemia, a childhood myeloproliferative/myelodysplastic disease caused by upregulated RAS signalling, defining an atypical form of this haematological disorder rapidly progressing to acute myeloid leukaemia. Two of the three identified mutations affected known oncogenic hotspots of RAS genes and conferred variably enhanced RRAS function and stimulus-dependent MAPK activation. Expression of an RRAS mutant homolog in Caenorhabditis elegans enhanced RAS signalling and engendered protruding vulva, a phenotype previously linked to the RASopathy-causing SHOC2(S2G) mutant. Overall, these findings provide evidence of a functional link between RRAS and MAPK signalling and reveal an unpredicted role of enhanced RRAS function in human disease.


Assuntos
Carcinogênese/genética , Mutação/fisiologia , Fenótipo , Proteínas ras/genética , Animais , Caenorhabditis elegans , Estudos de Coortes , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mielomonocítica Juvenil/genética , MAP Quinase Quinase Quinases/metabolismo , Síndrome de Noonan/genética , Proteína Oncogênica v-akt/metabolismo , Transdução de Sinais/genética , Proteínas ras/química , Proteínas ras/metabolismo
18.
Rev. bras. mastologia ; 23(4): 124-129, out-dez 2013. tab
Artigo em Português | LILACS-Express | LILACS | ID: lil-783161

RESUMO

As principais alterações encontradas após cirurgia de câncer de mama são disfunção articular no ombro e linfedema do membro superior homolateral à cirurgia, as quais podem prejudicar a qualidade de vida e a qualidade do sono das mulheres operadas. O objetivo do presente estudo foi verificar se a qualidade de sono e a força muscular estão prejudicadas em pacientes com e sem linfedema após cirurgia de câncer de mama. Estudo transversal analítico realizado com voluntárias após tratamento cirúrgico para câncer de mama, que desenvolveram (grupo linfedema) e que não desenvolveram (grupo controle) linfedema de membro superior, selecionadas no Ambulatório da Disciplina de Mastologia da Universidade Federal de São Paulo. Foi utilizado o questionário de índice de qualidade de sono de Pittsburgh (PSQI), a força muscular foi avaliada através do dinamômetro manual Lafayette® e ao final foi entregue cartilha de higiene do sono. Os dados foram compilados no Excel e o programa estatístico utilizado foi o SigmaStat 3.5®. Houve diferença significante quanto à comparação da perimetria entre os grupos, em seis de oito medidas, caracterizando o grupo linfedema; diminuição da força muscular no lado homolateral à cirurgia, sendo o grupo linfedema o mais alterado. O sono esteve prejudicado nos dois grupos, porém, com queixas diferentes. No grupo linfedema, a principal queixa foi quanto ao posicionamento para dormir e ao enfaixamento compressivo. Observou-se alteração do sono e da força muscular das mulheres que realizaram tratamento cirúrgico para o câncer de mama, sendo pior nas mulheres que desenvolveram o linfedema.


The most common consequences of breast cancer surgery includes joint dysfunction in the ipsilateral shoulder surgery and lymphedema of the upper limb ipsilateral to surgery. Such changes may affect the quality of life and women?s quality of sleep. The purpose of this study was to verify if the quality of sleep and the muscle strength are impaired in patients after surgical treatment for breast cancer, who developed and who didn?t develop lymphedema. An analytical cross study was developed with volunteers after surgical treatment for breast cancer who developed (lymphedema group) and who not developed (control group) lymphedema of the upper limb, in the Clinic of Mastology of the Federal University of São Paulo, Brazil. The questionnaire used was the Pittsburgh Sleep Quality Index (PSQI); muscle strength was assessed by manual dynamometer Lafayette® and in the end it was handed in a booklet of sleep hygiene. The data were put in Excel program and the statistic program used was the SigmaStat 3.5®. There were significant results regarding the perimeter difference between groups in six of eight measures characterizing the group lymphedema; decreased muscle strength was noted in the ipsilateral side to surgery in both groups, being the lymphedema group more affected. Sleep was impaired in both groups, but with different complaints. In the lymphedema group the main complaint was about the position for sleep and compressive bandaging. There was a change in sleeping and muscle strength of women who underwent surgical treatment for breast cancer, being worse in women who developed lymphedema

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