RESUMO
Next-generation sequencing (NGS) assays based on plasma cell-free DNA (cfDNA) are increasingly used for clinical trials inclusion. Their optimized limit of detection applied to a large number of genes leads to the identification of mutations not confirmed in tissue. It becomes essential to describe the characteristics and consequences of these liquid biopsy-only mutations. In the STING protocol (Gustave Roussy, NCT04932525), 542 patients with advanced solid cancer had cfDNA-based and tissue-based NGS analysis (performed by FoundationOne® Liquid CDx and FoundationOne CDx™, respectively). Mutations identified in the liquid biopsy but not in the paired tissue were considered as liquid biopsy-only mutations irrespective of their variant allelic frequency (VAF). Out of 542 patients, 281 (51.8%) harbored at least one liquid biopsy-only mutation. These patients were significantly older, and more heavily pretreated. Liquid biopsy-only mutations occurring in TP53, and in DDR genes (ATM, CHEK2, ATR, BRCA2, and BRCA1) accounted for 90.8% of all the mutations. The median VAF of these mutations was generally low (0.37% and 0.40% for TP53 and DDR genes respectively). The variant type repartition depended on the gene. Liquid biopsy-only mutations affected hotspot in TP53 codon 273, 125, 195, 176, 237 or 280 and ATM codon 2891 and 3008. In a subset of 37 patients, 75.0%, 53.5% and 83.3% of the liquid biopsy-only mutations occurring respectively in ATM, TP53, and CHEK2 were confirmed in the matching whole blood sample. Although liquid biopsy-only mutations makes the interpretation of liquid biopsy results more complex, they have distinct characteristics making them more easily identifiable.
RESUMO
BRCA2 is a clinically actionable gene implicated in breast and ovarian cancer predisposition that has become a high priority target for improving the classification of variants of unknown significance (VUS). Among all BRCA2 VUS, those causing partial/leaky splicing defects are the most challenging to classify because the minimal level of full-length (FL) transcripts required for normal function remains to be established. Here, we explored BRCA2 exon 3 (BRCA2e3) as a model for calibrating variant-induced spliceogenicity and estimating thresholds for BRCA2 haploinsufficiency. In silico predictions, minigene splicing assays, patients' RNA analyses, a mouse embryonic stem cell (mESC) complementation assay and retrieval of patient-related information were combined to determine the minimal requirement of FL BRCA2 transcripts. Of 100 BRCA2e3 variants tested in the minigene assay, 64 were found to be spliceogenic, causing mild to severe RNA defects. Splicing defects were also confirmed in patients' RNA when available. Analysis of a neutral leaky variant (c.231T>G) showed that a reduction of approximately 60% of FL BRCA2 transcripts from a mutant allele does not cause any increase in cancer risk. Moreover, data obtained from mESCs suggest that variants causing a decline in FL BRCA2 with approximately 30% of wild-type are not pathogenic, given that mESCs are fully viable and resistant to DNA-damaging agents in those conditions. In contrast, mESCs producing lower relative amounts of FL BRCA2 exhibited either null or hypomorphic phenotypes. Overall, our findings are likely to have broader implications on the interpretation of BRCA2 variants affecting the splicing pattern of other essential exons. SIGNIFICANCE: These findings demonstrate that BRCA2 tumor suppressor function tolerates substantial reduction in full-length transcripts, helping to determine the pathogenicity of BRCA2 leaky splicing variants, some of which may not increase cancer risk.
Assuntos
Neoplasias da Mama/genética , Genes BRCA2 , Predisposição Genética para Doença/genética , Neoplasias Ovarianas/genética , Processamento Alternativo , Animais , Éxons , Feminino , Humanos , Camundongos , Isoformas de ProteínasRESUMO
Nijmegen breakage syndrome caused by biallelic pathogenic variants of the DNA-damage response gene NBN, is characterized by severe microcephaly, cancer proneness, infertility, and karyotype abnormalities. We previously reported NBN variants in siblings suffering from fertility defects. Here, we identify a new founder NBN variant (c.442A>G, p.(Thr148Ala)) in Lebanese patients associated with isolated infertility. Functional analyses explored preserved or altered functions correlated with their remarkably mild phenotype. Transcript and protein analyses supported the use of an alternative transcript with in-frame skipping of exons 4-5, leading to p84-NBN protein with a preserved forkhead-associated (FHA) domain. The level of NBN was dramatically reduced and the MRN complex delocalized to the cytoplasm. Interestingly, ataxia-elangiectasia mutated (ATM) also shifted from the nucleus to the cytoplasm, suggesting some interaction between ATM and the MRN complex at a steady state. The ATM pathway activation, attenuated in typical patients with NBS, appeared normal under camptothecin treatment in these new NBN-related infertile patients. Cell cycle checkpoint defect was present in these atypical patients, although to a lesser extent than in typical patients with NBS. In conclusion, we report three new NBN-related infertile patients and we suggest that preserved FHA domain could be responsible for the mild phenotype and intermediate DNA-damage response defects.
Assuntos
Proteínas de Ciclo Celular/genética , Reparo do DNA , Estudos de Associação Genética , Predisposição Genética para Doença , Variação Genética , Infertilidade/diagnóstico , Infertilidade/genética , Proteínas Nucleares/genética , Adulto , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas de Ciclo Celular/metabolismo , Análise Mutacional de DNA , Feminino , Citometria de Fluxo , Regulação da Expressão Gênica , Estudos de Associação Genética/métodos , Humanos , Infertilidade/metabolismo , Masculino , Síndrome de Quebra de Nijmegen/diagnóstico , Síndrome de Quebra de Nijmegen/genética , Síndrome de Quebra de Nijmegen/metabolismo , Proteínas Nucleares/metabolismo , Ligação Proteica , Transdução de SinaisRESUMO
Ataxia-telangiectasia (A-T) is a recessive disorder caused by biallelic pathogenic variants of ataxia-telangiectasia mutated (ATM). This disease is characterized by progressive ataxia, telangiectasia, immune deficiency, predisposition to malignancies, and radiosensitivity. However, hypomorphic variants may be discovered associated with very atypical phenotypes, raising the importance of evaluating their pathogenic effects. In this study, multiple functional analyses were performed on lymphoblastoid cell lines from 36 patients, comprising 49 ATM variants, 24 being of uncertain significance. Thirteen patients with atypical phenotype and presumably hypomorphic variants were of particular interest to test strength of functional analyses and to highlight discrepancies with typical patients. Western-blot combined with transcript analyses allowed the identification of one missing variant, confirmed suspected splice defects and revealed unsuspected minor transcripts. Subcellular localization analyses confirmed the low level and abnormal cytoplasmic localization of ATM for most A-T cell lines. Interestingly, atypical patients had lower kinase defect and less altered cell-cycle distribution after genotoxic stress than typical patients. In conclusion, this study demonstrated the pathogenic effects of the 49 variants, highlighted the strength of KAP1 phosphorylation test for pathogenicity assessment and allowed the establishment of the Ataxia-TeLangiectasia Atypical Score to predict atypical phenotype. Altogether, we propose strategies for ATM variant detection and classification.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Variação Genética , Processamento Alternativo , Ciclo Celular , Linhagem Celular , Análise Mutacional de DNA , Estudos de Associação Genética/métodos , Genótipo , Humanos , Mutação , FenótipoRESUMO
Ataxia-telangiectasia-like disorder (ATLD) is a rare genomic instability syndrome caused by biallelic variants of MRE11 (meiotic recombination 11) characterized by progressive cerebellar ataxia and typical karyotype abnormalities. These symptoms are common to those of ataxia-telangiectasia, which is consistent with the key role of MRE11 in ataxia-telangiectasia mutated (ATM) activation after DNA double-strand breaks. Three unrelated French patients were referred with ataxia. Only one had typical karyotype abnormalities. Unreported biallelic MRE11 variants were found in these three cases. Interestingly, one variant (c.424G>A) was present in two cases and haplotype analysis strongly suggested a French founder variant. Variants c.544G>A and c.314+4_314+7del lead to splice defects. The level of MRE11 in lymphoblastoid cell lines was consistently and dramatically reduced. Functional consequences were evaluated on activation of the ATM pathway via phosphorylation of ATM targets (KAP1 and CHK2), but no consistent defect was observed. However, an S-phase checkpoint activation defect after camptothecin was observed in these patients with ATLD. In conclusion, we report the first three French ATLD patients and a French founder variant, and propose an S-phase checkpoint activation study to evaluate the pathogenicity of MRE11 variants.
Assuntos
Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/etiologia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Linhagem Celular Tumoral , Criança , Suscetibilidade a Doenças , Feminino , Perfilação da Expressão Gênica , Estudos de Associação Genética , Predisposição Genética para Doença , Haplótipos , Humanos , Lactente , Proteína Homóloga a MRE11/genética , Proteína Homóloga a MRE11/metabolismo , Imageamento por Ressonância Magnética , Mutação , Fenótipo , Splicing de RNA , Pontos de Checagem da Fase S do Ciclo Celular/genética , Transdução de Sinais , TranscriptomaRESUMO
BACKGROUND: Ataxia telangiectasia (A-T) is a neurodegenerative disorder. While patients with classic A-T generally die in their 20s, some patients with variant A-T, who have residual ataxia-telangiectasia mutated (ATM) kinase activity, have a milder phenotype. We noticed two commonly occurring ATM mutations that appeared to be associated with prolonged survival and decided to study patients carrying one of these mutations. METHODS: Data were retrospectively collected from the Dutch, Italian, German and French A-T cohorts. To supplement these data, we searched the literature for patients with identical genotypes. RESULTS: This study included 35 patients who were homozygous or compound heterozygous for the ATM c.3576G>A; p.(Ser1135_Lys1192del58) mutation and 24 patients who were compound heterozygous for the ATM c.8147T>C; p.(Val2716Ala) mutation. Compared with 51 patients with classic A-T from the Dutch cohort, patients with ATM c.3576G>A had a longer survival and were less likely to develop cancer, respiratory disease or immunodeficiency. This was also true for patients with ATM c.8147T>C, who additionally became wheelchair users later in life and had fewer telangiectasias. The oldest patient with A-T reported so far was a 78-year-old patient who was compound heterozygous for ATM c.8147T>C. ATM kinase activity was demonstrated in cells from all patients tested with the ATM c.8147T>C mutant protein and only at a low level in some patients with ATM c.3576G>A. CONCLUSION: Compared with classic A-T, the presence of ATM c.3576G>A results in a milder classic phenotype. Patients with ATM c.8147T>C have a variant phenotype with prolonged survival, which in exceptional cases may approach a near-normal lifespan.
Assuntos
Alelos , Proteínas Mutadas de Ataxia Telangiectasia/genética , Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/genética , Estudos de Associação Genética , Genótipo , Mutação , Fenótipo , Ataxia Telangiectasia/mortalidade , Humanos , Prognóstico , Sítios de Splice de RNA , Deleção de Sequência , Índice de Gravidade de DoençaAssuntos
Neoplasias da Mama/genética , Neoplasias Colorretais/genética , Exodesoxirribonucleases/genética , Predisposição Genética para Doença , Neoplasias Ovarianas/genética , Códon sem Sentido , Biologia Computacional , Endodesoxirribonucleases , Feminino , Mutação da Fase de Leitura , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Enzimas Multifuncionais , LinhagemRESUMO
BACKGROUND: V(D)J recombination ensures the diversity of the adaptive immune system. Although its complete defect causes severe combined immunodeficiency (ie, T-B- severe combined immunodeficiency), its suboptimal activity is associated with a broad spectrum of immune manifestations, such as late-onset combined immunodeficiency and autoimmunity. The earliest molecular diagnosis of these patients is required to adopt the best therapy strategy, particularly when it involves a myeloablative conditioning regimen for hematopoietic stem cell transplantation. OBJECTIVE: We aimed at developing biomarkers based on analysis of the T-cell receptor (TCR) α repertoire to assist in the diagnosis of patients with primary immunodeficiencies with V(D)J recombination and DNA repair deficiencies. METHODS: We used flow cytometric (fluorescence-activated cell sorting) analysis to quantify TCR-Vα7.2-expressing T lymphocytes in peripheral blood and developed PROMIDISα, a multiplex RT-PCR/next-generation sequencing assay, to evaluate a subset of the TCRα repertoire in T lymphocytes. RESULTS: The combined fluorescence-activated cell sorting and PROMIDISα analyses revealed specific signatures in patients with V(D)J recombination-defective primary immunodeficiencies or ataxia telangiectasia/Nijmegen breakage syndromes. CONCLUSION: Analysis of the TCRα repertoire is particularly appropriate in a prospective way to identify patients with partial immune defects caused by suboptimal V(D)J recombination activity, a DNA repair defect, or both. It also constitutes a valuable tool for the retrospective in vivo functional validation of variants identified through exome or panel sequencing. Its broader implementation might be of interest to assist early diagnosis of patients presenting with hypomorphic DNA repair defects inclined to experience acute toxicity during prehematopoietic stem cell transplantation conditioning.
Assuntos
Síndromes de Imunodeficiência , Receptores de Antígenos de Linfócitos T alfa-beta , Recombinação V(D)J/imunologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/imunologia , Síndromes de Imunodeficiência/patologia , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Estudos RetrospectivosAssuntos
Transformação Celular Neoplásica/genética , Endodesoxirribonucleases/fisiologia , Melanoma/genética , Mutagênese/genética , Neoplasias Uveais/genética , Transformação Celular Neoplásica/efeitos da radiação , Análise Mutacional de DNA , Endodesoxirribonucleases/genética , Humanos , Melanoma/patologia , Mutagênese/efeitos da radiação , Fenótipo , Mutação Puntual , Timina DNA Glicosilase/genética , Timina DNA Glicosilase/metabolismo , Raios Ultravioleta , Neoplasias Uveais/patologiaRESUMO
Metastatic uveal melanoma is a deadly disease with no proven standard of care. Here we present a metastatic uveal melanoma patient with an exceptional high sensitivity to a PD-1 inhibitor associated with outlier CpG>TpG mutation burden, MBD4 germline deleterious mutation, and somatic MBD4 inactivation in the tumor. We identify additional tumors in The Cancer Genome Atlas (TCGA) cohorts with similar hypermutator profiles in patients carrying germline deleterious MBD4 mutations and somatic loss of heterozygosity. This MBD4-related hypermutator phenotype may explain unexpected responses to immune checkpoint inhibitors.
Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Endodesoxirribonucleases/genética , Mutação em Linhagem Germinativa , Melanoma/genética , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Neoplasias Uveais/genética , Idoso , Atlas como Assunto , Ilhas de CpG , Endodesoxirribonucleases/imunologia , Enucleação Ocular , Feminino , Genoma Humano , Humanos , Perda de Heterozigosidade , Metástase Linfática , Melanoma/tratamento farmacológico , Melanoma/imunologia , Melanoma/cirurgia , Fenótipo , Mutação Puntual , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/imunologia , Neoplasias Uveais/tratamento farmacológico , Neoplasias Uveais/imunologia , Neoplasias Uveais/cirurgiaRESUMO
The invalidation of the Mismatch Repair (MMR) system is responsible for a so-called "deficient MMR" phenotype (dMMR) characterized by microsatellite instability and abnormal pattern of expression of MMR proteins in tumor tissue. This phenotype occurs in at least 20% of sporadic endometrial adenocarcinomas by epigenetic silencing of MLH1 gene. It is also observed in virtually all tumors occurring in patients with Lynch syndrome by monoallelic germline mutation in one of the MMR genes. The determination of this phenotype (dMMR vs. proficient MMR-pMMR) has therefore a pivotal place in the diagnosis algorithm for Lynch syndrome by monoallelic germline mutation in one of the MMR genes. The determination of this phenotype (dMMR vs. proficient MMR-pMMR) has therefore a pivotal place in the diagnosis algorithm for Lynch syndrome. We report the case of a woman with an early-onset endometrial adenocarcinoma who was suspected to be affected with Lynch syndrome based on tumor dMMR phenotype (MSI associated with loss of expression of MSH2 and MSH6 proteins). After complete germline and somatic evaluations, this phenotype was eventually explained by two MSH2 somatic mutations and the diagnosis of Lynch-like syndrome due to an unidentified MSH2 germline mutation was ruled out. Somatic mosaicism at low mutation rate was unlikely as no mutation was detected by DNA analysis from various tissue samples. Nevertheless, the three patient's children were tested for the two mutations and these tests were negative. Biallelic somatic mutations of one MMR gene is a mechanism of invalidation of the MMR system in sporadic cases. Clinicians have to be aware of this mechanism because of the great clinical implication for the patients and their relatives.
Assuntos
Adenocarcinoma/genética , Reparo de Erro de Pareamento de DNA/genética , Neoplasias do Endométrio/genética , Proteína 2 Homóloga a MutS/genética , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Idade de Início , Proteínas de Ligação a DNA/metabolismo , Neoplasias do Endométrio/diagnóstico por imagem , Neoplasias do Endométrio/patologia , Neoplasias do Endométrio/cirurgia , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Humanos , Imageamento por Ressonância Magnética , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Proteína 2 Homóloga a MutS/metabolismoRESUMO
BACKGROUND: Lung cancer represents the leading cause of cancer-related death worldwide. Despite great advances in lung cancer management with the recent emergence of molecular targeted therapies for non-squamous non-small-cell lung cancer, no dramatic improvements have been achieved in lung squamous cell carcinoma (SCC). Mutations in discoidin domain receptor 2 (DDR2) gene were recently identified as promising molecular targets in this histology. The aim of this study is to describe the DDR2 mutational landscape of lung SCC and investigate the associated clinical factors. METHODS: Next-generation sequencing of the DDR2 gene was performed on 271 samples of lung SCC. Patients followed in our institution from January 2011 to August 2014 were retrospectively selected for data collection. Other driver gene alterations (EGFR, KRAS, BRAF, HER2, and PI3KCA) were analyzed using pyrosequencing. RESULTS: A total of 11 patients harboring a DDR2 mutation was detected among the 271 sequenced lung SCC samples (4%). We describe 10 unreported mutations, comprising a novel DDR2 exon 7 splice mutant. DDR2 mutations were not mutually exclusive with other driver gene alterations. One hundred thirty-six patients were included for clinical comparison and logistic regression analysis. No difference was detected between DDR2-mutant and DDR2 wild-type lung SCC regarding clinical characteristics or survival. CONCLUSION: DDR2 mutations were observed in 4% of cases of lung SCC of European descent. DDR2-mutated tumors can exhibit other driver gene alterations. No clinical characteristics were significantly associated with DDR2 mutation.
Assuntos
Carcinoma de Células Escamosas/genética , Receptor com Domínio Discoidina 2/genética , Éxons/genética , Neoplasias Pulmonares/genética , Mutação/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Estudos de Coortes , Análise Mutacional de DNA , Feminino , Seguimentos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Análise de Sobrevida , População BrancaRESUMO
The tumor suppressor BAP1 associates with ASXL1/2 to form the core Polycomb complex PR-DUB, which catalyzes the removal of mono-ubiquitin from several substrates including histone H2A. This complex also mediates the poly-deubiquitination of HCFC1, OGT and PCG1-α, preventing them from proteasomal degradation. Surprisingly, considering its role in a Polycomb complex, no transcriptional signature was consistently found among BAP1-inactivated tumor types. It was hypothesized that BAP1 tumor suppressor activity could reside, at least in part, in stabilizing proteins through its poly-deubiquitinase activity. Quantitative mass spectrometry and gene expression arrays were used to investigate the consequences of BAP1 expression modulation in the NCI-H226 mesothelioma cell line. Analysis of differentially expressed proteins revealed enrichment in cytoskeleton organization, mitochondrial activity and ROS management, while gene expression analysis revealed enrichment in the epithelial-to-mesenchymal transition pathway. Functional assessments in BAP1 inactivated, BAP1 wild-type and BAP1 catalytically dead-expressing NCI-H226 and QR mesothelioma cell lines confirmed alteration of these pathways and demonstrated that BAP1 deubiquitinase activity was mandatory to maintain these phenotypes. Interestingly, monitoring intracellular ROS levels partly restored the morphology and the mitochondrial activity. Finally, the study suggests new tumorigenic and cellular functions of BAP1 and shows for the first time the interest of studying the proteome as readout of BAP1 inactivation.
RESUMO
Ataxia Telangiectasia (A-T) is caused by biallelic inactivation of the Ataxia Telangiectasia Mutated (ATM) gene, due to nonsense or missense mutations, small insertions/deletions (indels), splicing alterations, and large genomic rearrangements. After establishing A-T clinical diagnosis, a molecular confirmation is needed, based on the detection of one of these loss-of-function mutations in at least one allele. In most cases, the pathogenicity of the detected mutations is sufficient to make a definitive diagnosis. More rarely, mutations of unknown consequences are identified and direct biological analyses are required to establish their pathogenic characters. In such cases, complementary analyses of ATM expression, localization, and activity allow fine characterization of these mutations and facilitate A-T diagnosis. Here, we present genetic and biochemical protocols currently used in the laboratory that have proven to be highly accurate, reproducible, and quantitative. We also provide additional discussion on the critical points of the techniques presented here.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Ataxia Telangiectasia/genética , Análise Mutacional de DNA , Humanos , Mutação/genética , Mutação de Sentido Incorreto/genética , Proteínas Supressoras de Tumor/genéticaRESUMO
OBJECTIVE: The aim of this study was to document the association between pancreatic agenesis or hypoplasia and multicystic renal dysplasia related to transcription factor 2 (TCF2) or hepatocyte nuclear factor 1 beta mutations. METHODOLOGY: We describe the phenotype of the pancreas and the kidneys from three fetuses heterozygous for a mutation of TCF2. CASES: Case 1 had bilateral hyperechogenic, multicystic kidneys, bilateral clubfoot and pancreatic agenesis. Case 2 had two enlarged polycystic kidneys, anamnios and pancreatic agenesis. Case 3 had multicystic renal dysplasia, oligohydramnios and hypoplasia of the tail of the pancreas. CONCLUSION: TCF2 mutations are frequently discovered in fetuses presenting with bilateral hyperechogenic kidneys. The association between pancreatic agenesis and a TCF2 mutation has not previously been reported. TCF2 deficiency in mice leads to pancreatic agenesis, suggesting that the gene is essential for pancreatic development. Our observations indicate the importance of visualizing the pancreas during ultrasound examinations if renal malformations are discovered.
Assuntos
Fator 1-beta Nuclear de Hepatócito/genética , Rim Displásico Multicístico/genética , Mutação , Pâncreas/anormalidades , Adulto , Pé Torto Equinovaro/genética , Feminino , Idade Gestacional , Heterozigoto , Humanos , Rim Displásico Multicístico/diagnóstico por imagem , Rim Displásico Multicístico/patologia , Oligo-Hidrâmnio/genética , Pâncreas/diagnóstico por imagem , Pâncreas/patologia , Fenótipo , Gravidez , Ultrassonografia Pré-NatalRESUMO
This report concerns a 3-year-old girl with prenatal bilateral nephroblastomatosis and a family history of nephroblastoma. This girl had a chromosome 8 pericentric inversion inherited from her father. This inversion was observed in healthy individuals of the family and was absent in other individuals suffering from embryonic kidney tumor. We then supposed that another genetic anomaly predisposed her to tumorogenesis. Additional cryptic imbalances are reported in cases of apparently balanced chromosomal rearrangements with an abnormal phenotype. Array-CGH analysis showed a 569 kb duplication at 2p24.3 including the DDX1 and MYCN genes. This duplication was inherited from the patient's father who also had a nephroblastoma. A link between germline MYCN duplication and the occurrence of other embryonic cancers such as neuroblastoma has already been described. We supposed that germline DDX1-MYCN duplication could also be involved in the apparition of nephroblastomas.