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1.
J Invest Dermatol ; 144(9): 2066-2077.e6, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38431221

RESUMO

Common capillary malformations are red vascular skin lesions, most commonly associated with somatic activating GNAQ or GNA11 mutations. We focused on capillary malformations lacking such a mutation to identify previously unreported genetic causes. We used targeted next-generation sequencing on 82 lesions. Bioinformatic analysis allowed the identification of 9 somatic pathogenic variants in PIK3R1 and PIK3CA, encoding for the regulatory and catalytic subunits of phosphoinositide 3-kinase, respectively. Recharacterization of these lesions unraveled a common phenotype: a pale capillary malformation associated with visible dilated veins. Primary endothelial cells from 2 PIK3R1-mutated lesions were isolated, and PI3k-Akt-mTOR and RAS-RAF-MAPK signaling were assessed by western blot. This unveiled an abnormal increase in Akt phosphorylation, effectively reduced by PI3K pathway inhibitors, such as mTOR, Akt, and PIK3CA inhibitors. The effects of mutant PIK3R1 were further studied using zebrafish embryos. Endothelium-specific expression of PIK3R1 mutants resulted in abnormal development of the posterior capillary-venous plexus. In summary, capillary malformation associated with visible dilated veins emerges as a clinical entity associated with somatic pathogenic variants in PIK3R1 or PIK3CA (nonhotspot). Our findings suggest that the activated Akt signaling can be effectively reversed by PI3K pathway inhibitors. In addition, the proposed zebrafish model holds promise as a valuable tool for future drug screening aimed at developing patient-tailored treatments.


Assuntos
Capilares , Classe I de Fosfatidilinositol 3-Quinases , Classe Ia de Fosfatidilinositol 3-Quinase , Malformações Vasculares , Peixe-Zebra , Humanos , Classe I de Fosfatidilinositol 3-Quinases/genética , Peixe-Zebra/genética , Capilares/anormalidades , Capilares/patologia , Animais , Classe Ia de Fosfatidilinositol 3-Quinase/genética , Masculino , Feminino , Malformações Vasculares/genética , Malformações Vasculares/patologia , Adulto , Mutação com Perda de Função , Pessoa de Meia-Idade , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Transdução de Sinais/genética , Veias/anormalidades , Veias/patologia , Sequenciamento de Nucleotídeos em Larga Escala , Criança , Adolescente , Idoso
2.
Am J Med Genet A ; 194(6): e63551, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38321651

RESUMO

Capillary malformations (CMs) are the most common type of vascular anomalies, affecting around 0.3% of newborns. They are usually caused by somatic pathogenic variants in GNAQ or GNA11. PIK3CA and PIK3R1, part of the phosphoinositide 3-kinase-protein kinase B-mammalian target of rapamycin pathway, are mutated in fainter CMs such as diffuse CM with overgrowth and megalencephaly CM. In this study, we present two young patients with a CM-like phenotype associated with cerebral anomalies and severe epilepsy. Pathogenic variants in PIK3CA and PIK3R1, as well as GNAQ and GNA11, were absent in affected cutaneous tissue biopsies. Instead, we identified two somatic pathogenic variants in the AKT3 gene. Subsequent analysis of the DNA obtained from surgically resected brain tissue of one of the two patients confirmed the presence of the AKT3 variant. Focal cortical dysplasia was also detected in this patient. Genetic analysis thus facilitated workup to reach a precise diagnosis for these patients, associating the vascular anomaly with the neurological symptoms. This study underscores the importance of searching for additional signs and symptoms to guide the diagnostic workup, especially in cases with atypical vascular malformations. In addition, it strongly emphasizes the significance of genotype-phenotype correlation studies in guiding clinicians' informed decision-making regarding patient care.


Assuntos
Capilares , Epilepsia , Proteínas Proto-Oncogênicas c-akt , Telangiectasia , Malformações Vasculares , Feminino , Humanos , Recém-Nascido , Masculino , Capilares/anormalidades , Capilares/patologia , Epilepsia/genética , Epilepsia/patologia , Estudos de Associação Genética , Predisposição Genética para Doença , Mosaicismo , Mutação/genética , Fenótipo , Proteínas Proto-Oncogênicas c-akt/genética , Telangiectasia/genética , Telangiectasia/patologia , Telangiectasia/diagnóstico , Malformações Vasculares/genética , Malformações Vasculares/patologia , Malformações Vasculares/diagnóstico , Malformações Vasculares/complicações , Adolescente
3.
Eur J Cancer ; 195: 113372, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37913682

RESUMO

BACKGROUND: Only 15-20% of recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN) patients derive long-term benefit from nivolumab or pembrolizumab. We developed a circulating tumour DNA (ctDNA) tumour-agnostic assay aimed at the early prediction of single agent programmed cell death 1 (PD1) inhibitor efficacy in R/M SCCHN. PATIENTS AND METHODS: Our tumour-agnostic assay included 37 genes frequently mutated in R/M SCCHN and two HPV16 genes. Primary endpoint was the concordance between ctDNA kinetics (ΔctDNA) and the best overall response according to Response Evaluation Criteria in Solid Tumors version 1.1. ΔctDNA was defined as the difference in mean variant allele frequency (VAF) between the on-treatment sample harvested 6-10 weeks (FU1) after PD1 inhibitor initiation and the pre-treatment plasma sample (ΔctDNA = mean FU1 VAF - mean pre-treatment VAF). RESULTS: ctDNA was detected in 35/44 (80%) of the pre-treatment plasma samples. The concordance between ΔctDNA and imaging response was observed in 74%. Median progression-free survival was 8.6 months in the favourable ΔctDNA group and 2.5 months in the unfavourable ΔctDNA group (p = 0.057). Median overall survival (OS) was 18.1 and 8.2 months in the favourable and unfavourable ΔctDNA groups, respectively (p = 0.13). In patients with PD-L1 expressing SCCHN (Combined Positive Score ≥1), OS was significantly better in patients with favourable ΔctDNA compared with patients with unfavourable ΔctDNA: median OS was 41.5 and 8.4 months (p = 0.033), respectively. CONCLUSIONS: Tumour-agnostic ctDNA analysis for human papillomavirus (HPV)-negative and HPV-positive R/M SCCHN is feasible. ctDNA kinetics show promising results in predicting the efficacy of PD1 inhibitors in R/M SCCHN.


Assuntos
Carcinoma de Células Escamosas , DNA Tumoral Circulante , Neoplasias de Cabeça e Pescoço , Infecções por Papillomavirus , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Inibidores de Checkpoint Imunológico/uso terapêutico , DNA Tumoral Circulante/genética , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/genética , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/secundário
4.
JCI Insight ; 6(15)2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34156985

RESUMO

Gorham-Stout disease (GSD) is a sporadically occurring lymphatic disorder. Patients with GSD develop ectopic lymphatics in bone, gradually lose bone, and can have life-threatening complications, such as chylothorax. The etiology of GSD is poorly understood, and current treatments for this disease are inadequate for most patients. To explore the pathogenesis of GSD, we performed targeted high-throughput sequencing with samples from a patient with GSD and identified an activating somatic mutation in KRAS (p.G12V). To characterize the effect of hyperactive KRAS signaling on lymphatic development, we expressed an active form of KRAS (p.G12D) in murine lymphatics (iLECKras mice). We found that iLECKras mice developed lymphatics in bone, which is a hallmark of GSD. We also found that lymphatic valve development and maintenance was altered in iLECKras mice. Because most iLECKras mice developed chylothorax and died before they had significant bone disease, we analyzed the effect of trametinib (an FDA-approved MEK1/2 inhibitor) on lymphatic valve regression in iLECKras mice. Notably, we found that trametinib suppressed this phenotype in iLECKras mice. Together, our results demonstrate that somatic activating mutations in KRAS can be associated with GSD and reveal that hyperactive KRAS signaling stimulates the formation of lymphatics in bone and impairs the development of lymphatic valves. These findings provide insight into the pathogenesis of GSD and suggest that trametinib could be an effective treatment for GSD.


Assuntos
Osso e Ossos/patologia , Vasos Linfáticos , Osteólise Essencial , Proteínas Proto-Oncogênicas p21(ras)/genética , Piridonas/farmacologia , Pirimidinonas/farmacologia , Acrilonitrila/análogos & derivados , Acrilonitrila/farmacologia , Compostos de Anilina/farmacologia , Animais , Modelos Animais de Doenças , Mutação com Ganho de Função , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Linfangiogênese/genética , Vasos Linfáticos/anormalidades , Vasos Linfáticos/patologia , Camundongos , Osteólise Essencial/genética , Osteólise Essencial/patologia , Transdução de Sinais , Estruturas Linfoides Terciárias/genética , Estruturas Linfoides Terciárias/patologia
5.
Orphanet J Rare Dis ; 16(1): 267, 2021 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-34112235

RESUMO

BACKGROUND: Theragnostic management, treatment according to precise pathological molecular targets, requests to unravel patients' genotypes. We used targeted next-generation sequencing (NGS) or digital droplet polymerase chain reaction (ddPCR) to screen for somatic PIK3CA mutations on DNA extracted from resected lesional tissue or lymphatic endothelial cells (LECs) isolated from lesions. Our cohort (n = 143) was composed of unrelated patients suffering from a common lymphatic malformation (LM), a combined lymphatic malformation [lymphatico-venous malformation (LVM), capillaro-lymphatic malformation (CLM), capillaro-lymphatico-venous malformation (CLVM)], or a syndrome [CLVM with hypertrophy (Klippel-Trenaunay-Weber syndrome, KTS), congenital lipomatous overgrowth-vascular malformations-epidermal nevi -syndrome (CLOVES), unclassified PIK3CA-related overgrowth syndrome (PROS) or unclassified vascular (lymphatic) anomaly syndrome (UVA)]. RESULTS: We identified a somatic PIK3CA mutation in resected lesions of 108 out of 143 patients (75.5%). The frequency of the variant allele ranged from 0.54 to 25.33% in tissues, and up to 47% in isolated endothelial cells. We detected a statistically significant difference in the distribution of mutations between patients with common and combined LM compared to the syndromes, but not with KTS. Moreover, the variant allele frequency was higher in the syndromes. CONCLUSIONS: Most patients with an common or combined lymphatic malformation with or without overgrowth harbour a somatic PIK3CA mutation. However, in about a quarter of patients, no such mutation was detected, suggesting the existence of (an)other cause(s). We detected a hotspot mutation more frequently in common and combined LMs compared to syndromic cases (CLOVES and PROS). Diagnostic genotyping should thus not be limited to PIK3CA hotspot mutations. Moreover, the higher mutant allele frequency in syndromes suggests a wider distribution in patients' tissues, facilitating detection. Clinical trials have demonstrated efficacy of Sirolimus and Alpelisib in treating patients with an LM or PROS. Genotyping might lead to an increase in efficacy, as treatments could be more targeted, and responses could vary depending on presence and type of PIK3CA-mutation.


Assuntos
Síndrome de Klippel-Trenaunay-Weber , Lipoma , Anormalidades Linfáticas , Malformações Vasculares , Classe I de Fosfatidilinositol 3-Quinases/genética , Células Endoteliais , Humanos , Mutação
6.
Breast Cancer Res ; 22(1): 36, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32295625

RESUMO

BACKGROUND: Multigene panels are routinely used to assess for predisposing germline mutations in families at high breast cancer risk. The number of variants of unknown significance thereby identified increases with the number of sequenced genes. We aimed to determine whether tumor sequencing can help refine the analysis of germline variants based on second somatic genetic events in the same gene. METHODS: Whole-exome sequencing (WES) was performed on whole blood DNA from 70 unrelated breast cancer patients referred for genetic testing and without a BRCA1, BRCA2, TP53, or CHEK2 mutation. Rare variants were retained in a list of 735 genes. WES was performed on matched tumor DNA to identify somatic second hits (copy number alterations (CNAs) or mutations) in the same genes. Distinct methods (among which immunohistochemistry, mutational signatures, homologous recombination deficiency, and tumor mutation burden analyses) were used to further study the role of the variants in tumor development, as appropriate. RESULTS: Sixty-eight patients (97%) carried at least one germline variant (4.7 ± 2.0 variants per patient). Of the 329 variants, 55 (17%) presented a second hit in paired tumor tissue. Of these, 53 were CNAs, resulting in tumor enrichment (28 variants) or depletion (25 variants) of the germline variant. Eleven patients received variant disclosure, with clinical measures for five of them. Seven variants in breast cancer-predisposing genes were considered not implicated in oncogenesis. One patient presented significant tumor enrichment of a germline variant in the oncogene ERBB2, in vitro expression of which caused downstream signaling pathway activation. CONCLUSION: Tumor sequencing is a powerful approach to refine variant interpretation in cancer-predisposing genes in high-risk breast cancer patients. In this series, the strategy provided clinically relevant information for 11 out of 70 patients (16%), adapted to the considered gene and the familial clinical phenotype.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Sequenciamento do Exoma/métodos , Testes Genéticos/métodos , Mutação em Linhagem Germinativa , Adulto , Idoso , Variações do Número de Cópias de DNA , Feminino , Predisposição Genética para Doença , Humanos , Pessoa de Meia-Idade , Gradação de Tumores , Fatores de Risco
7.
Oral Oncol ; 104: 104631, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32169746

RESUMO

OBJECTIVES: The molecular landscape of head and neck squamous cell carcinoma (HNSCC) harbors potentially actionable genomic alterations. We aimed to study the utility of liquid biopsy to (i) characterize the mutational landscape of recurrent/metastatic HNSCC using a comprehensive gene panel and (ii) estimate the concordance between DNA mutations identified from circulating tumor DNA (ctDNA) and matched tumor tissues. MATERIALS AND METHODS: Targeted next-generation sequencing (NGS) was performed on cell-free DNA (cfDNA) of 39 patients with locoregional recurrent (n = 19) and/or metastatic (n = 20) HNSCC. Tumor biopsy (n = 18) was sequenced using the same technique. RESULTS: ctDNA was detected in 51% of patients (20/39) with a higher probability of detection in metastatic than locoregional recurrent disease (70% versus 30%, p = 0.025). 81% and 58% of the tissue tumor variants were not detected in plasma when considering all patients and only metastatic patients with detectable ctDNA, respectively. In a multivariate analysis, the likelihood of detecting the tissue tumor variant in plasma was related to metastatic status (p = 0.012), tumor variant allele frequency (p < 0.001) and ctDNA quantity (p < 0.001). 26% of the variants were detected only in liquid and not in the solid biopsy. Three patients without an available tumor sample had plasma containing three different potentially actionable PIK3CA mutations. CONCLUSION: CtDNA detection and characterization using targeted NGS is feasible in metastatic HNSCC. Liquid biopsies do not reflect the complete mutation profile of the tumor but have the potential to identify actionable mutations when tumor biopsies are not available as well as variants not found in matched tumor tissue.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala/métodos , Biópsia Líquida/métodos , Carcinoma de Células Escamosas de Cabeça e Pescoço/cirurgia , Feminino , Humanos , Masculino , Metástase Neoplásica , Recidiva Local de Neoplasia
8.
J Med Genet ; 57(1): 48-52, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31300548

RESUMO

BACKGROUND: Capillary malformation-arteriovenous malformation is an autosomal dominant disorder, characterised by capillary malformations and increased risk of fast-flow vascular malformations, caused by loss-of-function mutations in the RASA1 or EPHB4 genes. Around 25% of the patients do not seem to carry a germline mutation in either one of these two genes. Even if other genes could be involved, some individuals may have mutations in the known genes that escaped detection by less sensitive techniques. We tested the hypothesis that mosaic mutations could explain some of previously negative cases. METHODS: DNA was extracted from peripheral blood lymphocytes, saliva or vascular malformation tissues from four patients. RASA1 and EPHB4 coding regions and exon/intron boundaries were analysed by targeted custom gene panel sequencing. A second panel and/or Sanger sequencing were used to confirm the identified mutations. RESULTS: Four distinct mosaic RASA1 mutations, with an allele frequency ranging from 3% to 25%, were identified in four index patients with classical capillary malformation-arteriovenous malformation phenotype. Three mutations were known, one was novel. In one patient, a somatic second hit was also identified. One index case had three affected children, illustrating that the mosaicism was also present in the germline. CONCLUSION: This study shows that RASA1 mosaic mutations can cause capillary malformation-arteriovenous malformation. Thus, highly sensitive sequencing techniques should be considered as diagnostic tools, especially for patients with no family history. Even low-level mosaicism can cause the classical phenotype and increased risk for offspring. In addition, our study further supports the second-hit pathophysiological mechanism to explain the multifocality of vascular lesions in this disorder.


Assuntos
Malformações Arteriovenosas/genética , Capilares/anormalidades , Mosaicismo , Mutação , Mancha Vinho do Porto/genética , Proteína p120 Ativadora de GTPase/genética , Malformações Arteriovenosas/diagnóstico , Malformações Arteriovenosas/metabolismo , Capilares/metabolismo , Análise Mutacional de DNA , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mancha Vinho do Porto/diagnóstico , Mancha Vinho do Porto/metabolismo
9.
Mem. Inst. Oswaldo Cruz ; 115: e200504, 2020. graf
Artigo em Inglês | LILACS, Sec. Est. Saúde SP | ID: biblio-1135260

RESUMO

BACKGROUND Biodiversity screens and phylogenetic studies are dependent on reliable DNA sequences in public databases. Biological collections possess vouchered specimens with a traceable history. Therefore, DNA sequencing of samples available at institutional collections can greatly contribute to taxonomy, and studies on evolution and biodiversity. METHODS We sequenced part of the glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) and the SSU rRNA (V7/V8) genes from 102 trypanosomatid cultures, which are available on request at www.colprot.fiocruz.br. OBJECTIVE The main objective of this work was to use phylogenetic inferences, using the obtained DNA sequences and those from representatives of all Trypanosomatidae genera, to generate phylogenetic trees that can simplify new isolates screenings. FINDINGS A DNA sequence is provided for the first time for several isolates, the phylogenetic analysis allowed the classification or reclassification of several specimens, identification of candidates for new genera and species, as well as the taxonomic validation of several deposits. MAIN CONCLUSIONS This survey aimed at presenting a list of validated species and their associated DNA sequences combined with a short historical overview of each isolate, which can support taxonomic and biodiversity research and promote culture collections.


Assuntos
Trypanosomatina/classificação , Trypanosomatina/genética , Biodiversidade , Código de Barras de DNA Taxonômico , Filogenia
10.
J Med Genet ; 55(7): 449-458, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29500247

RESUMO

BACKGROUND: Oral clefts, that is, clefts of the lip and/or cleft palate (CL/P), are the most common craniofacial birth defects with an approximate incidence of ~1/700. To date, physicians stratify patients with oral clefts into either syndromic CL/P (syCL/P) or non-syndromic CL/P (nsCL/P) depending on whether the CL/P is associated with another anomaly or not. In general, patients with syCL/P follow Mendelian inheritance, while those with nsCL/P have a complex aetiology and, as such, do not adhere to Mendelian inheritance. Genome-wide association studies have identified approximately 30 risk loci for nsCL/P, which could explain a small fraction of heritability. METHODS: To identify variants causing nsCL/P, we conducted whole exome sequencing on 84 individuals with nsCL/P, drawn from multiplex families (n=46). RESULTS: We identified rare damaging variants in four genes known to be mutated in syCL/P: TP63 (one family), TBX1 (one family), LRP6 (one family) and GRHL3 (two families), and clinical reassessment confirmed the isolated nature of their CL/P. CONCLUSION: These data demonstrate that patients with CL/P without cardinal signs of a syndrome may still carry a mutation in a gene linked to syCL/P. Rare coding and non-coding variants in syCL/P genes could in part explain the controversial question of 'missing heritability' for nsCL/P. Therefore, gene panels designed for diagnostic testing of syCL/P should be used for patients with nsCL/P, especially when there is at least third-degree family history. This would allow a more precise management, follow-up and genetic counselling. Moreover, stratified cohorts would allow hunting for genetic modifiers.


Assuntos
Anormalidades Múltiplas/genética , Encéfalo/anormalidades , Fenda Labial/genética , Fissura Palatina/genética , Proteínas de Ligação a DNA/genética , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteínas com Domínio T/genética , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor/genética , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/fisiopatologia , Adulto , Encéfalo/fisiopatologia , Pré-Escolar , Fenda Labial/diagnóstico , Fenda Labial/fisiopatologia , Fissura Palatina/diagnóstico , Fissura Palatina/fisiopatologia , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Masculino , Mutação/genética , Linhagem , Polimorfismo de Nucleotídeo Único/genética , Sequenciamento do Exoma/métodos , Adulto Jovem
11.
Circulation ; 136(11): 1037-1048, 2017 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-28687708

RESUMO

BACKGROUND: Most arteriovenous malformations (AVMs) are localized and occur sporadically. However, they also can be multifocal in autosomal-dominant disorders, such as hereditary hemorrhagic telangiectasia and capillary malformation (CM)-AVM. Previously, we identified RASA1 mutations in 50% of patients with CM-AVM. Herein we studied non-RASA1 patients to further elucidate the pathogenicity of CMs and AVMs. METHODS: We conducted a genome-wide linkage study on a CM-AVM family. Whole-exome sequencing was also performed on 9 unrelated CM-AVM families. We identified a candidate gene and screened it in a large series of patients. The influence of several missense variants on protein function was also studied in vitro. RESULTS: We found evidence for linkage in 2 loci. Whole-exome sequencing data unraveled 4 distinct damaging variants in EPHB4 in 5 families that cosegregated with CM-AVM. Overall, screening of EPHB4 detected 47 distinct mutations in 54 index patients: 27 led to a premature stop codon or splice-site alteration, suggesting loss of function. The other 20 are nonsynonymous variants that result in amino acid substitutions. In vitro expression of several mutations confirmed loss of function of EPHB4. The clinical features included multifocal CMs, telangiectasias, and AVMs. CONCLUSIONS: We found EPHB4 mutations in patients with multifocal CMs associated with AVMs. The phenotype, CM-AVM2, mimics RASA1-related CM-AVM1 and also hereditary hemorrhagic telangiectasia. RASA1-encoded p120RASGAP is a direct effector of EPHB4. Our data highlight the pathogenetic importance of this interaction and indicts EPHB4-RAS-ERK signaling pathway as a major cause for AVMs.


Assuntos
Malformações Arteriovenosas/diagnóstico , Malformações Arteriovenosas/genética , Capilares/anormalidades , Mutação em Linhagem Germinativa/genética , Sistema de Sinalização das MAP Quinases/fisiologia , Mancha Vinho do Porto/diagnóstico , Mancha Vinho do Porto/genética , Receptor EphB4/genética , Proteína p120 Ativadora de GTPase/genética , Bases de Dados Genéticas , Feminino , Estudo de Associação Genômica Ampla/métodos , Humanos , Masculino , Linhagem
13.
Hum Mol Genet ; 26(10): 1801-1810, 2017 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-28334876

RESUMO

Infantile myofibromatosis is one of the most prevalent soft tissue tumors of infancy and childhood. Multifocal nodules with visceral lesions are associated with a poor prognosis. A few familial cases have been linked to mutations in various genes including PDGFRB. In this study, we sequenced PDGFRB, which encodes a receptor tyrosine kinase, in 16 cases of myofibromatosis or solitary myofibroma. Mutations in the coding sequence of PDGFRB were identified in 6 out of 8 patients with the sporadic multicentric form of the disease and in 1 out of 8 patients with isolated myofibroma. Two patients had the same mutation in multiple separated lesions. By contrast, a third patient had three different PDGFRB mutations in the three nodules analyzed. Mutations were located in the transmembrane, juxtamembrane and kinase domains of the receptor. We showed that these mutations activated receptor signaling in the absence of ligand and transformed fibroblasts. In one case, a weakly-activating germline variant was associated with a stronger somatic mutation, suggesting a two-hit model for familial myofibromatosis. Furthermore, the mutant receptors were sensitive to the tyrosine kinase inhibitor imatinib, except D850V, which was inhibited by dasatinib and ponatinib, suggesting a targeted therapy for severe myofibromatosis. In conclusion, we identified gain-of-function PDGFRB mutations in the majority of multifocal infantile myofibromatosis cases, shedding light on the mechanism of disease development, which is reminiscent of multifocal venous malformations induced by TIE2 mutations. Our results provide a genetic test to facilitate diagnosis, and preclinical data for development of molecular therapies.


Assuntos
Mutação , Miofibromatose/congênito , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Miofibromatose/genética , Miofibromatose/metabolismo , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Receptor TIE-2/genética
14.
J Invest Dermatol ; 137(1): 207-216, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27519652

RESUMO

Blue rubber bleb nevus syndrome (Bean syndrome) is a rare, severe disorder of unknown cause, characterized by numerous cutaneous and internal venous malformations; gastrointestinal lesions are pathognomonic. We discovered somatic mutations in TEK, the gene encoding TIE2, in 15 of 17 individuals with blue rubber bleb nevus syndrome. Somatic mutations were also identified in five of six individuals with sporadically occurring multifocal venous malformations. In contrast to common unifocal venous malformation, which is most often caused by the somatic L914F TIE2 mutation, multifocal forms are predominantly caused by double (cis) mutations, that is, two somatic mutations on the same allele of the gene. Mutations are identical in all lesions from a given individual. T1105N-T1106P is recurrent in blue rubber bleb nevus, whereas Y897C-R915C is recurrent in sporadically occurring multifocal venous malformation: both cause ligand-independent activation of TIE2, and increase survival, invasion, and colony formation when expressed in human umbilical vein endothelial cells.


Assuntos
Neoplasias Gastrointestinais/genética , Predisposição Genética para Doença/epidemiologia , Mutação , Nevo Azul/genética , Receptor TIE-2/genética , Neoplasias Cutâneas/genética , Malformações Vasculares/genética , Bélgica , Estudos de Coortes , Feminino , Neoplasias Gastrointestinais/diagnóstico , Humanos , Incidência , Masculino , Nevo Azul/diagnóstico , Doenças Raras , Neoplasias Cutâneas/diagnóstico , Malformações Vasculares/diagnóstico
15.
Am J Hum Genet ; 97(6): 914-21, 2015 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-26637981

RESUMO

Somatic mutations in TEK, the gene encoding endothelial cell tyrosine kinase receptor TIE2, cause more than half of sporadically occurring unifocal venous malformations (VMs). Here, we report that somatic mutations in PIK3CA, the gene encoding the catalytic p110α subunit of PI3K, cause 54% (27 out of 50) of VMs with no detected TEK mutation. The hotspot mutations c.1624G>A, c.1633G>A, and c.3140A>G (p.Glu542Lys, p.Glu545Lys, and p.His1047Arg), frequent in PIK3CA-associated cancers, overgrowth syndromes, and lymphatic malformation (LM), account for >92% of individuals who carry mutations. Like VM-causative mutations in TEK, the PIK3CA mutations cause chronic activation of AKT, dysregulation of certain important angiogenic factors, and abnormal endothelial cell morphology when expressed in human umbilical vein endothelial cells (HUVECs). The p110α-specific inhibitor BYL719 restores all abnormal phenotypes tested, in PIK3CA- as well as TEK-mutant HUVECs, demonstrating that they operate via the same pathogenic pathways. Nevertheless, significant genotype-phenotype correlations in lesion localization and histology are observed between individuals with mutations in PIK3CA versus TEK, pointing to gene-specific effects.


Assuntos
Mutação , Neovascularização Patológica/genética , Fosfatidilinositol 3-Quinases/genética , Malformações Vasculares/genética , Alelos , Classe I de Fosfatidilinositol 3-Quinases , Regulação da Expressão Gênica , Frequência do Gene , Estudos de Associação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/enzimologia , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Neovascularização Patológica/enzimologia , Neovascularização Patológica/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/farmacologia , Receptor TIE-2/antagonistas & inibidores , Receptor TIE-2/genética , Receptor TIE-2/metabolismo , Transdução de Sinais , Tiazóis/farmacologia , Transfecção , Malformações Vasculares/enzimologia , Malformações Vasculares/patologia , Veias/enzimologia , Veias/patologia
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