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1.
Eur J Med Genet ; 63(1): 103617, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30664951

RESUMO

Mutations in LZTR1, already known to be causal in familial schwannomatosis type 2, have been recently involved in a small proportion of patients with autosomal dominant and autosomal recessive Noonan syndrome. LZTR1 is also a driver gene in non syndromal glioblastoma. We report a 26-year-old patient with typical Noonan syndrome, and the dominantly transmitted c.850C > T (p.(Arg284Cys)) variant in LZTR1. An oligoastrocytoma was diagnosed in the patient at the age of 22 years; recurrence of the tumor occurred at age 26, as a ganglioblastoma. The patient had been transiently treated with growth hormone between ages 15 and 17. Considering the implication of LZTR1 in sporadic tumors of the nervous system, we hypothesize that gliomas are a possible complication of LZTR1-related Noonan syndrome. This report also supports a possible link between occurrence of a cerebral tumor in Noonan syndrome and a previous treatment with growth hormone.


Assuntos
Astrocitoma/genética , Glioblastoma/genética , Síndrome de Noonan/genética , Fatores de Transcrição/genética , Adolescente , Adulto , Astrocitoma/complicações , Astrocitoma/diagnóstico , Astrocitoma/patologia , Feminino , Predisposição Genética para Doença , Glioblastoma/complicações , Glioblastoma/diagnóstico , Glioblastoma/patologia , Humanos , Masculino , Mutação , Síndrome de Noonan/complicações , Síndrome de Noonan/diagnóstico , Síndrome de Noonan/patologia , Linhagem
2.
Blood ; 134(25): 2304-2317, 2019 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-31562133

RESUMO

Src homology 2 domain-containing phosphatase 2 (SHP2), encoded by the PTPN11 gene, is a ubiquitous protein tyrosine phosphatase that is a critical regulator of signal transduction. Germ line mutations in the PTPN11 gene responsible for catalytic gain or loss of function of SHP2 cause 2 disorders with multiple organ defects: Noonan syndrome (NS) and NS with multiple lentigines (NSML), respectively. Bleeding anomalies have been frequently reported in NS, but causes remain unclear. This study investigates platelet activation in patients with NS and NSML and in 2 mouse models carrying PTPN11 mutations responsible for these 2 syndromes. Platelets from NS mice and patients displayed a significant reduction in aggregation induced by low concentrations of GPVI and CLEC-2 agonists and a decrease in thrombus growth on a collagen surface under arterial shear stress. This was associated with deficiencies in GPVI and αIIbß3 integrin signaling, platelet secretion, and thromboxane A2 generation. Similarly, arterial thrombus formation was significantly reduced in response to a local carotid injury in NS mice, associated with a significant increase in tail bleeding time. In contrast, NSML mouse platelets exhibited increased platelet activation after GPVI and CLEC-2 stimulation and enhanced platelet thrombotic phenotype on collagen matrix under shear stress. Blood samples from NSML patients also showed a shear stress-dependent elevation of platelet responses on collagen matrix. This study brings new insights into the understanding of SHP2 function in platelets, points to new thrombopathies linked to platelet signaling defects, and provides important information for the medical care of patients with NS in situations involving risk of bleeding.


Assuntos
Plaquetas/enzimologia , Mutação em Linhagem Germinativa , Síndrome de Noonan/enzimologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Transdução de Sinais , Animais , Plaquetas/patologia , Humanos , Camundongos , Camundongos Mutantes , Síndrome de Noonan/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética
3.
Am J Hum Genet ; 104(6): 1223-1232, 2019 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-31130282

RESUMO

Aberrant signaling through pathways controlling cell response to extracellular stimuli constitutes a central theme in disorders affecting development. Signaling through RAS and the MAPK cascade controls a variety of cell decisions in response to cytokines, hormones, and growth factors, and its upregulation causes Noonan syndrome (NS), a developmental disorder whose major features include a distinctive facies, a wide spectrum of cardiac defects, short stature, variable cognitive impairment, and predisposition to malignancies. NS is genetically heterogeneous, and mutations in more than ten genes have been reported to underlie this disorder. Despite the large number of genes implicated, about 10%-20% of affected individuals with a clinical diagnosis of NS do not have mutations in known RASopathy-associated genes, indicating that additional unidentified genes contribute to the disease, when mutated. By using a mixed strategy of functional candidacy and exome sequencing, we identify RRAS2 as a gene implicated in NS in six unrelated subjects/families. We show that the NS-causing RRAS2 variants affect highly conserved residues localized around the nucleotide binding pocket of the GTPase and are predicted to variably affect diverse aspects of RRAS2 biochemical behavior, including nucleotide binding, GTP hydrolysis, and interaction with effectors. Additionally, all pathogenic variants increase activation of the MAPK cascade and variably impact cell morphology and cytoskeletal rearrangement. Finally, we provide a characterization of the clinical phenotype associated with RRAS2 mutations.


Assuntos
Mutação com Ganho de Função , Guanosina Trifosfato/metabolismo , Proteínas de Membrana/genética , Proteínas Monoméricas de Ligação ao GTP/genética , Síndrome de Noonan/etiologia , Adulto , Criança , Feminino , Estudos de Associação Genética , Células HEK293 , Humanos , Lactente , Recém-Nascido , Masculino , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Proteínas Monoméricas de Ligação ao GTP/química , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Síndrome de Noonan/patologia , Linhagem , Conformação Proteica
4.
Am J Hum Genet ; 104(6): 1233-1240, 2019 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-31130285

RESUMO

Noonan syndrome (NS) is characterized by distinctive craniofacial appearance, short stature, and congenital heart disease. Approximately 80% of individuals with NS harbor mutations in genes whose products are involved in the RAS/mitogen-activating protein kinase (MAPK) pathway. However, the underlying genetic causes in nearly 20% of individuals with NS phenotype remain unexplained. Here, we report four de novo RRAS2 variants in three individuals with NS. RRAS2 is a member of the RAS subfamily and is ubiquitously expressed. Three variants, c.70_78dup (p.Gly24_Gly26dup), c.216A>T (p.Gln72His), and c.215A>T (p.Gln72Leu), have been found in cancers; our functional analyses showed that these three changes induced elevated association of RAF1 and that they activated ERK1/2 and ELK1. Notably, prominent activation of ERK1/2 and ELK1 by p.Gln72Leu associates with the severe phenotype of the individual harboring this change. To examine variant pathogenicity in vivo, we generated zebrafish models. Larvae overexpressing c.70_78dup (p.Gly24_Gly26dup) or c.216A>T (p.Gln72His) variants, but not wild-type RRAS2 RNAs, showed craniofacial defects and macrocephaly. The same dose injection of mRNA encoding c.215A>T (p.Gln72Leu) caused severe developmental impairments and low dose overexpression of this variant induced craniofacial defects. In contrast, the RRAS2 c.224T>G (p.Phe75Cys) change, located on the same allele with p.Gln72His in an individual with NS, resulted in no aberrant in vitro or in vivo phenotypes by itself. Together, our findings suggest that activating RRAS2 mutations can cause NS and expand the involvement of RRAS2 proto-oncogene to rare germline disorders.


Assuntos
Mutação com Ganho de Função , Mutação em Linhagem Germinativa , Proteínas de Membrana/genética , Proteínas Monoméricas de Ligação ao GTP/genética , Síndrome de Noonan/etiologia , Peixe-Zebra/crescimento & desenvolvimento , Sequência de Aminoácidos , Animais , Criança , Pré-Escolar , Exoma , Feminino , Humanos , Masculino , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Proteínas Monoméricas de Ligação ao GTP/química , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Síndrome de Noonan/patologia , Fenótipo , Conformação Proteica , Homologia de Sequência , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
5.
Horm Res Paediatr ; 91(1): 46-55, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30939478

RESUMO

BACKGROUND/AIMS: There is little information how rhGH treatment affects height in NS. This study aims to analyze data from the NS patients assembled in KIGS over 25 years. PATIENTS/METHODS: Of 613 (389 m/224 f) NS patients documented, 476 (302 m/174 f) were treated for 1 year, 237 (160 m/77 f) of which served to develop a 1st year height velocity (HV) prediction algorithm. One-hundred and forty (74 m/66 f) had reached near adult height (NAH). Factors affecting NAH on rhGH were determined. RESULTS: At the start of rhGH, the NAH groups were (median, m, f) 11.0 and 10.3 years, with a height SDS of -3.2 and -3.8 SDS (Prader), respectively. The total gain after 6.3 and 5.6 years on rhGH (0.27 and 0.30 mg/kg/week) was 1.2 and 1.3 SDS. Age at the start of rhGH (negative), height at the start of rhGH, rhGH dose, number of rhGH injections/wk and birth weight (all positive) explained 36% of the variability of 1st year HV. Height at the start of rhGH, 1st year growth on rhGH, birth weight, and gender explained 74% of the variability of NAH. Causes for rhGH treatment discontinuation and adverse events were also analyzed. CONCLUSION: rhGH treatment increases NAH in NS. Prediction algorithms may optimize treatment in the future.


Assuntos
Desenvolvimento do Adolescente/efeitos dos fármacos , Estatura/efeitos dos fármacos , Desenvolvimento Infantil/efeitos dos fármacos , Hormônio do Crescimento Humano/administração & dosagem , Síndrome de Noonan , Adolescente , Adulto , Fatores Etários , Criança , Feminino , Seguimentos , Humanos , Masculino , Síndrome de Noonan/tratamento farmacológico , Síndrome de Noonan/patologia , Síndrome de Noonan/fisiopatologia
6.
Am J Med Genet C Semin Med Genet ; 181(2): 208-217, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30896080

RESUMO

RASopathies are a group of genetic disorders due to dysregulation of the RAS-MAPK signaling pathway, which is important in regulating cell growth, proliferation, and differentiation. These include Noonan syndrome (NS), Noonan syndrome with multiple lentigines (NSML), cardiofaciocutaneous (CFC) syndrome, and Costello syndrome (CS), clinical manifestations include growth retardation, developmental delay, cardiac defects, and specific dysmorphic features. There were abundant publications describing the genotype and phenotype from the Western populations. However, detailed study of RASopathies in Chinese population is lacking. We present here the largest cohort of RASopathies ever reported in Chinese populations, detailing the mutation spectrum and clinical phenotypes of these patients. The Clinical Genetic Service, Department of Health, and Queen Mary Hospital are tertiary referral centers for genetic disorders in Hong Kong. We retrospectively reviewed all the genetically confirmed cases of RASopathies, including NS, NSML, CFC syndrome, and CS, over the past 29 years (from 1989 to 2017). Analyses of the mutation spectrum and clinical phenotypes were performed. One hundred and ninety-one ethnic Chinese patients with genetically confirmed RASopathies were identified, including 148 patients with NS, 23 NSML, 12 CFC syndrome, and eight CS. We found a lower incidence of hypertrophic cardiomyopathy in individuals with NSML (27.3%), and NS caused by RAF1 mutations (62.5%). Another significant finding was for those NS patients with myeloproliferative disorder, the mutations fall within Exon 3 of PTPN11 but not only restricted to the well-known hotspots, that is, p.Asp61 and p.Thr731, which suggested that re-evaluation of the current tumor surveillance recommendation maybe warranted.


Assuntos
Mutação , Fenótipo , Proteínas ras/genética , Síndrome de Costello/genética , Síndrome de Costello/patologia , Displasia Ectodérmica/genética , Displasia Ectodérmica/patologia , Facies , Insuficiência de Crescimento/genética , Insuficiência de Crescimento/patologia , Feminino , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/patologia , Hong Kong , Humanos , Síndrome LEOPARD/genética , Síndrome LEOPARD/patologia , Sistema de Sinalização das MAP Quinases/genética , Masculino , Síndrome de Noonan/genética , Síndrome de Noonan/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Estudos Retrospectivos
7.
Mol Genet Genomic Med ; 7(4): e00581, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30784236

RESUMO

BACKGROUND: Noonan syndrome (NS) is an autosomal dominant disorder that belongs to a group of developmental disorders called RASopathies with overlapping features and multiple causative genes. The aim of the study was to identify mutations underlying this disorder in patients from Southeast Asia and characterize their clinical presentations. METHODS: Patients were identified from the hospital's Genetics clinics after assessment by attending clinical geneticists. A targeted gene panel was used for next-generation sequencing on genomic DNA extracted from the blood samples of 17 patients. RESULTS: Heterozygous missense variants were identified in 13 patients: eight were in PTPN11, three in SOS1, and one each in RIT1 and KRAS. All are known variants that have been reported in patients with NS. Of the 13 patients with identified variants, 10 had short stature, the most common feature for NS. Four of the eight patients with PTPN11 variants had atrial septal defect. Only two had pulmonary stenosis which is reported to be common for PTPN11 mutation carriers. Another two had hypertrophic cardiomyopathy, a feature which is negatively associated with PTPN11 mutations. CONCLUSIONS: Our study provides the mutation and phenotypic spectrum of NS from a new population group. The molecular testing yield of 76% is similar to other studies and shows that the targeted panel approach is useful for identifying genetic mutations in NS which has multiple causative genes. The molecular basis for the phenotypes of the remaining patients remains unknown and would need to be uncovered via sequencing of additional genes or other investigative methods.


Assuntos
Taxa de Mutação , Síndrome de Noonan/genética , Fenótipo , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Mutação de Sentido Incorreto , Síndrome de Noonan/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteína SOS1/genética , Singapura , Proteínas ras/genética
8.
Pediatr Dev Pathol ; 22(4): 386-390, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30665336

RESUMO

Noonan syndrome is a genetic condition with a heterogeneous phenotype and multisystem involvement. The pathogenesis of this disorder has been attributed to the mutations in the RAS/MAPK signaling pathway involved in cell proliferation and differentiation. The most common clinical presentations are related to cardiovascular abnormalities with congestive heart failure as the most common mechanism of death. We present the autopsy findings from a Noonan syndrome patient who died as a result of an unusual form of right ventricular obstruction associated with a rare PTPN11 variant previously reported without details of the cardiac findings. Discussion follows that includes overview of the incidence, genetic causes, types of right-sided obstructive lesions, PTPN11 genotype-cardiac phenotype correlations, and other potential mechanisms that may contribute to disease heterogeneity.


Assuntos
Cardiomiopatia Hipertrófica/diagnóstico , Síndrome de Noonan/diagnóstico , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Transdução de Sinais/genética , Autopsia , Cardiomiopatia Hipertrófica/genética , Cardiomiopatia Hipertrófica/patologia , Humanos , Recém-Nascido , Masculino , Mutação , Mutação de Sentido Incorreto , Síndrome de Noonan/genética , Síndrome de Noonan/patologia , Fenótipo
9.
Hum Genet ; 138(1): 21-35, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30368668

RESUMO

RASopathies are a group of developmental disorders caused by mutations in genes that regulate the RAS/MAPK pathway and include Noonan syndrome (NS), Costello syndrome, cardiofaciocutaneous syndrome and other related disorders. Whole exome sequencing studies recently identified LZTR1, PPP1CB and MRAS as new causative genes in RASopathies. However, information on the phenotypes of LZTR1 mutation-positive patients and functional properties of the mutations are limited. To identify variants of LZTR1, PPP1CB, and MRAS, we performed a targeted next-generation sequencing and reexamined previously analyzed exome data in 166 patients with suspected RASopathies. We identified eight LZTR1 variants, including a de novo variant, in seven probands who were suspicious for NS and one known de novo PPP1CB variant in a patient with NS. One of the seven probands had two compound heterozygous LZTR1 variants, suggesting autosomal recessive inheritance. All probands with LZTR1 variants had cardiac defects, including hypertrophic cardiomyopathy and atrial septal defect. Five of the seven probands had short stature or intellectual disabilities. Immunoprecipitation of endogenous LZTR1 followed by western blotting showed that LZTR1 bound to the RAF1-PPP1CB complex. Cells transfected with a small interfering RNA against LZTR1 exhibited decreased levels of RAF1 phosphorylated at Ser259. These are the first results to demonstrate LZTR1 in association with the RAF1-PPP1CB complex as a component of the RAS/MAPK pathway.


Assuntos
Biomarcadores/análise , Mutação , Síndrome de Noonan/genética , Proteína Fosfatase 1/metabolismo , Proteínas Proto-Oncogênicas c-raf/metabolismo , Fatores de Transcrição/metabolismo , Adolescente , Adulto , Criança , Pré-Escolar , Exoma , Feminino , Seguimentos , Humanos , Masculino , Síndrome de Noonan/metabolismo , Síndrome de Noonan/patologia , Fenótipo , Prognóstico , Ligação Proteica , Proteína Fosfatase 1/genética , Proteínas Proto-Oncogênicas c-raf/genética , Fatores de Transcrição/genética , Adulto Jovem
12.
Cereb Cortex ; 29(7): 2915-2923, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-30059958

RESUMO

The Ras-MAPK pathway has an established role in neural development and synaptic signaling. Mutations in this pathway are associated with a collection of neurodevelopmental syndromes, Rasopathies; among these, Noonan syndrome (NS) is the most common (1:2000). Prior research has focused on identifying genetic mutations and cellular mechanisms of the disorder, however, effects of NS on the human brain remain unknown. Here, imaging and cognitive data were collected from 12 children with PTPN11-related NS, ages 4.0-11.0 years (8.98 ± 2.33) and 12 age- and sex-matched typically developing controls (8.79 ± 2.17). We observe reduced gray matter volume in bilateral corpus striatum (Cohen's d = -1.0:-1.3), reduced surface area in temporal regions (d = -1.8:-2.2), increased cortical thickness in frontal regions (d = 1.2-1.3), and reduced cortical thickness in limbic regions (d = -1.6), including limbic structures integral to the circuitry of the hippocampus. Further, we find high levels of inattention, hyperactivity, and memory deficits in children with NS. Taken together, these results identify effects of NS on specific brain regions associated with ADHD and learning in children. While our research lays the groundwork for elucidating the neural and behavioral mechanisms of NS, it also adds an essential tier to understanding the Ras-MAPK pathway's role in human brain development.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/genética , Encéfalo/patologia , Transtornos da Memória/genética , Síndrome de Noonan/genética , Síndrome de Noonan/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Atenção/fisiologia , Criança , Pré-Escolar , Feminino , Mutação com Ganho de Função , Humanos , Imagem por Ressonância Magnética , Masculino , Síndrome de Noonan/fisiopatologia
13.
BMC Med Genet ; 19(1): 212, 2018 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-30541462

RESUMO

BACKGROUND: Dwarfism is a common severe growth disorder, but the etiology is unclear in the majority of cases. Recombinant human growth hormone may be a treatment option, but it has limited efficacy. The currently known laboratory assays do not meet the precision requirements for clinical diagnosis. Here, we have constructed a targeted next-generation sequencing (NGS) panel of selected genes that are suspected to be associated with dwarfism for genetic screening. METHODS: Genetic screening of 91 children with short stature of unknown etiology was performed with the help of the NGS panel. All the coding regions and exon-intron boundaries of 166 genes were included in the panel. To clarify the pathogenicity of these mutations, their clinical data were reviewed and analyzed. RESULTS: The assay identified p.A72G, p.I282V, and p.P491S variants of the PTPN11 gene and a p.I437T variant of the SOS1 gene in 4 cases with Noonan syndrome. A frameshift mutation (p.D2407fs) of the ACAN gene was identified in a case of idiopathic short stature with moderately advanced bone age. A p.R904C variant of the COL2A1 gene was found in a patient, who was accordingly diagnosed with Stickler syndrome. Severe short stature without limb deformity was associated with a p.G11A variant of HOXD13. In addition, we evaluated evidence that a p.D401N variant of the COMP gene may cause multiple epiphyseal dysplasia. CONCLUSIONS: Our findings suggest that syndromes, particularly Noonan syndrome, may be overlooked due to atypical clinical features. This gene panel has been verified to be effective for the rapid screening of genetic etiologies associated with short stature and for guiding precision medicine-based clinical management.


Assuntos
Artrite/genética , Doenças do Tecido Conjuntivo/genética , Nanismo/genética , Perda Auditiva Neurossensorial/genética , Mutação , Síndrome de Noonan/genética , Osteocondrodisplasias/genética , Descolamento Retiniano/genética , Adolescente , Agrecanas/genética , Artrite/diagnóstico , Artrite/etnologia , Artrite/patologia , Grupo com Ancestrais do Continente Asiático , Proteína de Matriz Oligomérica de Cartilagem/genética , Criança , Pré-Escolar , Colágeno Tipo II/genética , Doenças do Tecido Conjuntivo/diagnóstico , Doenças do Tecido Conjuntivo/etnologia , Doenças do Tecido Conjuntivo/patologia , Nanismo/diagnóstico , Nanismo/etnologia , Nanismo/patologia , Feminino , Expressão Gênica , Testes Genéticos/métodos , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/etnologia , Perda Auditiva Neurossensorial/patologia , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas de Homeodomínio/genética , Humanos , Masculino , Síndrome de Noonan/diagnóstico , Síndrome de Noonan/etnologia , Síndrome de Noonan/patologia , Osteocondrodisplasias/diagnóstico , Osteocondrodisplasias/etnologia , Osteocondrodisplasias/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Descolamento Retiniano/diagnóstico , Descolamento Retiniano/etnologia , Descolamento Retiniano/patologia , Proteína SOS1/genética , Fatores de Transcrição/genética
14.
Int Heart J ; 59(5): 1096-1105, 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30101858

RESUMO

Hypertrophic cardiomyopathy (HCM) is a genetic disorder that is characterized by hypertrophy of the myocardium. Some of the patients are diagnosed for HCM during infancy, and the prognosis of infantile HCM is worse than general HCM. Nevertheless, pathophysiology of infantile HCM is less investigated and remains largely unknown. In the present study, we generated induced pluripotent stem cells (iPSCs) from two patients with infantile HCM: one with Noonan syndrome and the other with idiopathic HCM. We found that iPSC-derived cardiomyocytes (iPSC-CMs) from idiopathic HCM patient were significantly larger and showed higher diastolic intracellular calcium concentration compared with the iPSC-CMs from healthy subject. Unlike iPSC-CMs from the adult/adolescent HCM patient, arrhythmia was not observed as a disease-related phenotype in iPSC-CMs from idiopathic infantile HCM patient. Phenotypic screening revealed that Pyr3, a transient receptor potential channel 3 channel inhibitor, decreased both the cell size and diastolic intracellular calcium concentration in iPSC-CMs from both Noonan syndrome and idiopathic infantile HCM patients, suggesting that the target of Pyr3 may play a role in the pathogenesis of infantile HCM, regardless of the etiology. Further research may unveil the possibility of Pyr3 or its derivatives in the treatment of infantile HCM.


Assuntos
Cardiomiopatia Hipertrófica/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Programas de Rastreamento/métodos , Síndrome de Noonan/metabolismo , Canais de Receptores Transientes de Potencial/antagonistas & inibidores , Adulto , Cálcio/metabolismo , Cardiomiopatia Hipertrófica/diagnóstico , Cardiomiopatia Hipertrófica/tratamento farmacológico , Cardiomiopatia Hipertrófica/patologia , Pré-Escolar , Humanos , Masculino , Mutação , Miocárdio/patologia , Miócitos Cardíacos/patologia , Síndrome de Noonan/diagnóstico , Síndrome de Noonan/tratamento farmacológico , Síndrome de Noonan/patologia , Fenótipo , Prevalência , Canais de Receptores Transientes de Potencial/uso terapêutico
15.
Hum Mol Genet ; 27(13): 2276-2289, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29659837

RESUMO

Growth retardation is a constant feature of Noonan syndrome (NS) but its physiopathology remains poorly understood. We previously reported that hyperactive NS-causing SHP2 mutants impair the systemic production of insulin-like growth factor 1 (IGF1) through hyperactivation of the RAS/extracellular signal-regulated kinases (ERK) signalling pathway. Besides endocrine defects, a direct effect of these mutants on growth plate has not been explored, although recent studies have revealed an important physiological role for SHP2 in endochondral bone growth. We demonstrated that growth plate length was reduced in NS mice, mostly due to a shortening of the hypertrophic zone and to a lesser extent of the proliferating zone. These histological features were correlated with decreased expression of early chondrocyte differentiation markers, and with reduced alkaline phosphatase staining and activity, in NS murine primary chondrocytes. Although IGF1 treatment improved growth of NS mice, it did not fully reverse growth plate abnormalities, notably the decreased hypertrophic zone. In contrast, we documented a role of RAS/ERK hyperactivation at the growth plate level since 1) NS-causing SHP2 mutants enhance RAS/ERK activation in chondrocytes in vivo (NS mice) and in vitro (ATDC5 cells) and 2) inhibition of RAS/ERK hyperactivation by U0126 treatment alleviated growth plate abnormalities and enhanced chondrocyte differentiation. Similar effects were obtained by chronic treatment of NS mice with statins. In conclusion, we demonstrated that hyperactive NS-causing SHP2 mutants impair chondrocyte differentiation during endochondral bone growth through a local hyperactivation of the RAS/ERK signalling pathway, and that statin treatment may be a possible therapeutic approach in NS.


Assuntos
Condrócitos/metabolismo , Fator de Crescimento Insulin-Like I/genética , Síndrome de Noonan/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Animais , Butadienos/administração & dosagem , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Condrócitos/efeitos dos fármacos , Modelos Animais de Doenças , Lâmina de Crescimento/anormalidades , Lâmina de Crescimento/efeitos dos fármacos , Humanos , Fator de Crescimento Insulin-Like I/administração & dosagem , Sistema de Sinalização das MAP Quinases , Nitrilos/administração & dosagem , Síndrome de Noonan/tratamento farmacológico , Síndrome de Noonan/patologia
16.
Am J Hum Genet ; 102(2): 309-320, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29394990

RESUMO

Exome sequencing has markedly enhanced the discovery of genes implicated in Mendelian disorders, particularly for individuals in whom a known clinical entity could not be assigned. This has led to the recognition that phenotypic heterogeneity resulting from allelic mutations occurs more commonly than previously appreciated. Here, we report that missense variants in CDC42, a gene encoding a small GTPase functioning as an intracellular signaling node, underlie a clinically heterogeneous group of phenotypes characterized by variable growth dysregulation, facial dysmorphism, and neurodevelopmental, immunological, and hematological anomalies, including a phenotype resembling Noonan syndrome, a developmental disorder caused by dysregulated RAS signaling. In silico, in vitro, and in vivo analyses demonstrate that mutations variably perturb CDC42 function by altering the switch between the active and inactive states of the GTPase and/or affecting CDC42 interaction with effectors, and differentially disturb cellular and developmental processes. These findings reveal the remarkably variable impact that dominantly acting CDC42 mutations have on cell function and development, creating challenges in syndrome definition, and exemplify the importance of functional profiling for syndrome recognition and delineation.


Assuntos
Anormalidades Múltiplas/genética , Anormalidades Craniofaciais/genética , Heterogeneidade Genética , Atrofia Muscular/genética , Mutação de Sentido Incorreto , Transtornos do Neurodesenvolvimento/genética , Síndrome de Noonan/genética , Proteína cdc42 de Ligação ao GTP/genética , Anormalidades Múltiplas/metabolismo , Anormalidades Múltiplas/patologia , Adolescente , Adulto , Criança , Pré-Escolar , Anormalidades Craniofaciais/metabolismo , Anormalidades Craniofaciais/patologia , Feminino , Expressão Gênica , Humanos , Lactente , Masculino , Modelos Moleculares , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Transtornos do Neurodesenvolvimento/metabolismo , Transtornos do Neurodesenvolvimento/patologia , Síndrome de Noonan/metabolismo , Síndrome de Noonan/patologia , Fenótipo , Estrutura Secundária de Proteína , Índice de Gravidade de Doença , Proteína cdc42 de Ligação ao GTP/química , Proteína cdc42 de Ligação ao GTP/metabolismo
17.
Genet Med ; 20(10): 1175-1185, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29469822

RESUMO

PURPOSE: To characterize the molecular genetics of autosomal recessive Noonan syndrome. METHODS: Families underwent phenotyping for features of Noonan syndrome in children and their parents. Two multiplex families underwent linkage analysis. Exome, genome, or multigene panel sequencing was used to identify variants. The molecular consequences of observed splice variants were evaluated by reverse-transcription polymerase chain reaction. RESULTS: Twelve families with a total of 23 affected children with features of Noonan syndrome were evaluated. The phenotypic range included mildly affected patients, but it was lethal in some, with cardiac disease and leukemia. All of the parents were unaffected. Linkage analysis using a recessive model supported a candidate region in chromosome 22q11, which includes LZTR1, previously shown to harbor mutations in patients with Noonan syndrome inherited in a dominant pattern. Sequencing analyses of 21 live-born patients and a stillbirth identified biallelic pathogenic variants in LZTR1, including putative loss-of-function, missense, and canonical and noncanonical splicing variants in the affected children, with heterozygous, clinically unaffected parents and heterozygous or normal genotypes in unaffected siblings. CONCLUSION: These clinical and genetic data confirm the existence of a form of Noonan syndrome that is inherited in an autosomal recessive pattern and identify biallelic mutations in LZTR1.


Assuntos
Predisposição Genética para Doença , Síndrome de Noonan/genética , Fatores de Transcrição/genética , Adolescente , Criança , Pré-Escolar , Exoma/genética , Feminino , Ligação Genética , Genótipo , Heterozigoto , Humanos , Lactente , Masculino , Mutação , Síndrome de Noonan/patologia , Linhagem , Isoformas de Proteínas/genética , Processamento de RNA/genética , Irmãos
18.
Sci Rep ; 8(1): 2421, 2018 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-29402968

RESUMO

RASopathies are a group of heterogeneous conditions caused by germline mutations in RAS/MAPK signalling pathway genes. With next-generation sequencing (NGS), sequencing capacity is no longer a limitation to molecular diagnosis. Instead, the rising number of variants of unknown significance (VUSs) poses challenges to clinical interpretation and genetic counselling. We investigated the potential of an integrated pipeline combining NGS and the functional assessment of variants for the diagnosis of RASopathies. We included 63 Chinese patients with RASopathies that had previously tested negative for PTPN11 and HRAS mutations. In these patients, we performed a genetic analysis of genes associated with RASopathies using a multigene NGS panel and Sanger sequencing. For the VUSs, we evaluated evidence from genetic, bioinformatic and functional data. Twenty disease-causing mutations were identified in the 63 patients, providing a primary diagnostic yield of 31.7%. Four VUSs were identified in five patients. The functional assessment supported the pathogenicity of the RAF1 and RIT1 VUSs, while the significance of two VUSs in A2ML1 remained unclear. In summary, functional analysis improved the diagnostic yield from 31.7% to 36.5%. Although technically demanding and time-consuming, a functional genetic diagnostic analysis can ease the clinical translation of these findings to aid bedside interpretation.


Assuntos
Síndrome de Costello/genética , Displasia Ectodérmica/genética , Insuficiência de Crescimento/genética , Cardiopatias Congênitas/genética , Neurofibromatose 1/genética , Síndrome de Noonan/genética , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas ras/genética , Adolescente , Animais , Bioensaio , Criança , Pré-Escolar , Biologia Computacional , Síndrome de Costello/patologia , Displasia Ectodérmica/patologia , Facies , Insuficiência de Crescimento/patologia , Feminino , Expressão Gênica , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Mutação em Linhagem Germinativa , Cardiopatias Congênitas/patologia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , MAP Quinase Quinase 1/genética , Masculino , Mutação de Sentido Incorreto , Neurofibromatose 1/patologia , Síndrome de Noonan/patologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteína SOS1/genética , Peixe-Zebra , alfa-Macroglobulinas/genética
19.
Clin Genet ; 93(1): 138-143, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28456002

RESUMO

Neurofibromatosis type 1 (NF1) has long been considered a well-defined, recognizable monogenic disorder, with neurofibromas constituting a pathognomonic sign. This dogma has been challenged by recent descriptions of patients with enlarged nerves or paraspinal tumors, suggesting that neurogenic tumors and hypertrophic neuropathy may be a complication of Noonan syndrome with multiple lentigines (NSML) or RASopathy phenotype. We describe a 15-year-old boy, whose mother previously received clinical diagnosis of NF1 due to presence of bilateral cervical and lumbar spinal lesions resembling plexiform neurofibromas and features suggestive of NS. NF1 molecular analysis was negative in the mother. The boy presented with Noonan features, multiple lentigines and pectus excavatum. Next-generation sequencing analysis of all RASopathy genes identified p.Ser548Arg missense mutation in SOS1 in the boy, confirmed in his mother. Brain and spinal magnetic resonance imaging scans were negative in the boy. No heart involvement or deafness was observed in proband or mother. This is the first report of a SOS1 mutation associated with hypertrophic neuropathy resembling plexiform neurofibromas, a rare complication in Noonan phenotypes with mutations in RASopathy genes. Our results highlight the overlap between RASopathies, suggesting that NF1 diagnostic criteria need rethinking. Genetic analysis of RASopathy genes should be considered when diagnosis is uncertain.


Assuntos
Mutação de Sentido Incorreto , Neurofibromatose 1/genética , Síndrome de Noonan/genética , Proteína SOS1/genética , Nervos Espinhais/metabolismo , Adolescente , Adulto , Saúde da Família , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Mães , Neurofibromatose 1/patologia , Síndrome de Noonan/patologia , Fenótipo , Nervos Espinhais/patologia
20.
Exp Cell Res ; 362(2): 293-301, 2018 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-29197556

RESUMO

BACKGROUND: Recent reports have demonstrated that RAF-1L613V (a mutant of RAF-1) mutant mice show bone deformities similar to Noonan syndrome. It has been suggested that RAF-1L613V might abnormally activate osteoblast differentiation of MC3T3-E1 cells. METHODS: To demonstrate that RAF-1 is associated with bone deformity and that RAF-1L613V dependent bone deformity could be inhibited by microRNA-195 (miR-195), we first investigated the amplifying influence of wild-type RAF-1 (WT) or RAF-1L613V (L613V) on the viability and differentiation of MC3T3-E1 cells induced by bone morphogenetic protein-2 (BMP-2) via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) and Alizarin Red S (ARS) staining, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis. Subsequently, we investigated the blocking effect and its mechanism of miR-195 for abnormal activation of osteoblast differentiation of MC3T3-E1 cells via targeting RAF-1. RESULTS: RAF-1, especially RAF-1L613V, abnormally activates osteoblast differentiation of MC3T3-E1 cells induced by BMP-2. Meanwhile, miR-195 could inhibit the cell viability and differentiation of MC3T3-E1 cells. Transfection of miR-195 largely suppressed the L613V-induced viability and osteoblast differentiation of MC3T3-E1 cells and attenuated the accelerative effect of L613V on runt-related transcription factor-2 (Runx2), Osterix (OSX), alkaline phosphatase (ALP), osteocalcin (OCN), and distal-less homeobox 5 (DLX5) osteogenic gene expressions. In addition, miR-195 decreased the expression of RAF-1 mRNA and protein by directly targeting the 3'-untranslated regions (3'-UTR) of RAF-1 mRNA in MC3T3-E1 cells. CONCLUSIONS: Our findings indicated that miR-195 inhibited WT and L613V RAF-1 induced hyperactive osteoblast differentiation in MC3T3-E1 cells by targeting RAF-1. miR-195 might be a novel therapeutic agent for the treatment of L613V-induced bone deformity in Noonan syndrome.


Assuntos
Diferenciação Celular/genética , MicroRNAs/genética , Síndrome de Noonan/genética , Osteogênese/genética , Proteínas Proto-Oncogênicas c-raf/genética , Células 3T3-L1 , Animais , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Camundongos , Mutação , Síndrome de Noonan/patologia , Osteoblastos , Osteocalcina/genética , Transfecção
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