Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Med Genet ; 56(8): 521-525, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30580288

RESUMO

IMPORTANCE: Genetic testing of hereditary cancer using comprehensive gene panels can identify patients with more than one pathogenic mutation in high and/or moderate-risk-associated cancer genes. This phenomenon is known as multilocus inherited neoplasia alleles syndrome (MINAS), which has been potentially linked to more severe clinical manifestations. OBJECTIVE: To determine the prevalence and clinical features of MINAS in a large cohort of adult patients with hereditary cancer homogeneously tested with the same gene panel. PATIENTS AND METHODS: A cohort of 1023 unrelated patients with suspicion of hereditary cancer was screened using a validated panel including up to 135 genes associated with hereditary cancer and phakomatoses. RESULTS: Thirteen (1.37%) patients harbouring two pathogenic mutations in dominant cancer-predisposing genes were identified, representing 5.7% (13/226) of patients with pathogenic mutations. Most (10/13) of these cases presented clinical manifestations associated with only one of the mutations identified. One case showed mutations in MEN1 and MLH1 and developed tumours associated with both cancer syndromes. Interestingly, three of the double mutants had a young age of onset or severe breast cancer phenotype and carried mutations in moderate to low-risk DNA damage repair-associated genes; two of them presented biallelic inactivation of CHEK2. We included these two patients for the sake of their clinical interest although we are aware that they do not exactly fulfil the definition of MINAS since both mutations are in the same gene. CONCLUSIONS AND RELEVANCE: Genetic analysis of a broad cancer gene panel identified the largest series of patients with MINAS described in a single study. Overall, our data do not support the existence of more severe manifestations in double mutants at the time of diagnosis although they do confirm previous evidence of severe phenotype in biallelic CHEK2 and other DNA repair cancer-predisposing genes.

2.
Br J Cancer ; 119(8): 978-987, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30283143

RESUMO

BACKGROUND: Constitutional MLH1 epimutations are characterised by monoallelic methylation of the MLH1 promoter throughout normal tissues, accompanied by allele-specific silencing. The mechanism underlying primary MLH1 epimutations is currently unknown. The aim of this study was to perform an in-depth characterisation of constitutional MLH1 epimutations targeting the aberrantly methylated region around MLH1 and other genomic loci. METHODS: Twelve MLH1 epimutation carriers, 61 Lynch syndrome patients, and 41 healthy controls, were analysed by Infinium 450 K array. Targeted molecular techniques were used to characterise the MLH1 epimutation carriers and their inheritance pattern. RESULTS: No nucleotide or structural variants were identified in-cis on the epimutated allele in 10 carriers, in which inter-generational methylation erasure was demonstrated in two, suggesting primary type of epimutation. CNVs outside the MLH1 locus were found in two cases. EPM2AIP1-MLH1 CpG island was identified as the sole differentially methylated region in MLH1 epimutation carriers compared to controls. CONCLUSION: Primary constitutional MLH1 epimutations arise as a focal epigenetic event at the EPM2AIP1-MLH1 CpG island in the absence of cis-acting genetic variants. Further molecular characterisation is needed to elucidate the mechanistic basis of MLH1 epimutations and their heritability/reversibility.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais/genética , Metilação de DNA/genética , Epigênese Genética/genética , Predisposição Genética para Doença/genética , Proteína 1 Homóloga a MutL/genética , Sequência de Bases , Neoplasias Colorretais/epidemiologia , Ilhas de CpG/genética , Feminino , Haplótipos/genética , Humanos , Masculino , Mutação/genética , Regiões Promotoras Genéticas/genética , Análise de Sequência de DNA
3.
Technol Health Care ; 24(6): 965-968, 2016 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-27447408

RESUMO

INTRODUCTION: Doctor-patient communication is essential to the establishment of a therapeutic relationship and to the clinical improvement of the patient. Medical Interpreter Services (MIS) allow the doctors to communicate with patients that do not speak the same language of the clinical staff. However, MIS are not always available and when that happens it is of the upmost importance to find alternatives. OBJECTIVES AND METHODS: Presentation of a clinical case in which Google Translate^© (GT^©) was used as a translation tool to communicate with a patient. Discussion of the utility and validity of GT^© as a translation tool in Medicine. A Pubmed search for articles concerning the use of technological innovations as translation tools was performed using the key words: GT^©, language barriers, foreign language, and communication barriers. RESULTS: In the reported clinical case, GT^© allowed the translation and the establishment of communication with a foreign patient. The Pubmed search found two articles concerning the use and validity of GT^© as a translation tool in Medicine. CONCLUSIONS: GT^© is the most readily available and free initial mode of communication between a doctor and a patient when language is a barrier. Nonetheless, GT^


Assuntos
Barreiras de Comunicação , Comunicação , Internet , Tradução , Adulto , Animais , Humanos , Masculino , Relações Médico-Paciente , Portugal , Ucrânia
4.
Breast Cancer Res Treat ; 155(2): 253-60, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26780556

RESUMO

Germline inactivating mutations in the BRCA1 and BRCA2 genes are responsible for hereditary breast and ovarian cancer syndrome (HBOCS). Genetic testing of these genes identifies a significant proportion of variants of uncertain significance (VUS). Elucidation of the clinical impact of these variants is an important challenge in genetic diagnostics and counseling. In this study, we assess the RNA effect of 28 BRCA1 and BRCA2 VUS identified in our set of HBOCS families with the aim of gaining insight into their clinical relevance. mRNA was extracted from VUS carriers and controls lymphocytes cultured for 5-6 days and treated with puromycin. RNA was reverse transcribed to perform transcriptional analysis for the study of splicing aberrations. In silico prediction tools were used to select those variants most likely to affect the RNA splicing process. Six out of the 28 variants analyzed showed an aberrant splicing pattern and could therefore be classified as probably pathogenic mutations. Reclassification of VUS improves the genetic counseling and clinical surveillance of carriers of these mutations and highlights the importance of RNA studies in routine diagnostic laboratories.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Mutação em Linhagem Germinativa/genética , Síndrome Hereditária de Câncer de Mama e Ovário/genética , RNA Mensageiro/genética , Feminino , Humanos , Processamento de RNA/genética , Transcrição Genética/genética
6.
Eur J Cancer ; 50(13): 2241-50, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24953332

RESUMO

BACKGROUND AND AIMS: Individuals with tumours showing mismatch repair (MMR) deficiency not linked to germline mutations or somatic methylation of MMR genes have been recently referred as having 'Lynch-like syndrome' (LLS). The genetic basis of these LLS cases is unknown. MUTYH-associated polyposis patients show some phenotypic similarities to Lynch syndrome patients. The aim of this study was to investigate the prevalence of germline MUTYH mutations in a large series of LLS patients. METHODS: Two hundred and twenty-five probands fulfilling LLS criteria were included in this study. Screening of MUTYH recurrent mutations, whole coding sequencing and a large rearrangement analysis were undertaken. Age, sex, clinical, pathological and molecular characteristics of tumours including KRAS mutations were assessed. RESULTS: We found a prevalence of 3.1% of MAP syndrome in the whole series of LLS (7/225) and 3.9% when only cases fulfilling clinical criteria were considered (7/178). Patients with MUTYH biallelic mutations had more adenomas than monoallelic (P=0.02) and wildtype patients (P<0.0001). Six out of nine analysed tumours from six biallelic MUTYH carriers harboured KRAS-p.G12C mutation. This mutation was found to be associated with biallelic MUTYH germline mutation when compared with reported series of unselected colorectal cancer cohorts (P<0.0001). CONCLUSIONS: A proportion of unexplained LLS cases is caused by biallelic MUTYH mutations. The obtained results further justify the inclusion of MUTYH in the diagnostic strategy for Lynch syndrome-suspected patients.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , DNA Glicosilases/genética , Mutação em Linhagem Germinativa , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas p21(ras) , Proteínas ras/genética
7.
Hum Mutat ; 35(3): 271-7, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24227591

RESUMO

Next-generation sequencing (NGS) has revolutionized genomic research and is set to have a major impact on genetic diagnostics thanks to the advent of benchtop sequencers and flexible kits for targeted libraries. Among the main hurdles in NGS are the difficulty of performing bioinformatic analysis of the huge volume of data generated and the high number of false positive calls that could be obtained, depending on the NGS technology and the analysis pipeline. Here, we present the development of a free and user-friendly Web data analysis tool that detects and filters sequence variants, provides coverage information, and allows the user to customize some basic parameters. The tool has been developed to provide accurate genetic analysis of targeted sequencing of common high-risk hereditary cancer genes using amplicon libraries run in a GS Junior System. The Web resource is linked to our own mutation database, to assist in the clinical classification of identified variants. We believe that this tool will greatly facilitate the use of the NGS approach in routine laboratories.


Assuntos
Biologia Computacional/métodos , Genes Neoplásicos , Testes Genéticos/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Internet , Genoma Humano , Genômica/métodos , Humanos , Interface Usuário-Computador
8.
Eur J Hum Genet ; 21(8): 864-70, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23249957

RESUMO

Next-generation sequencing (NGS) is changing genetic diagnosis due to its huge sequencing capacity and cost-effectiveness. The aim of this study was to develop an NGS-based workflow for routine diagnostics for hereditary breast and ovarian cancer syndrome (HBOCS), to improve genetic testing for BRCA1 and BRCA2. A NGS-based workflow was designed using BRCA MASTR kit amplicon libraries followed by GS Junior pyrosequencing. Data analysis combined Variant Identification Pipeline freely available software and ad hoc R scripts, including a cascade of filters to generate coverage and variant calling reports. A BRCA homopolymer assay was performed in parallel. A research scheme was designed in two parts. A Training Set of 28 DNA samples containing 23 unique pathogenic mutations and 213 other variants (33 unique) was used. The workflow was validated in a set of 14 samples from HBOCS families in parallel with the current diagnostic workflow (Validation Set). The NGS-based workflow developed permitted the identification of all pathogenic mutations and genetic variants, including those located in or close to homopolymers. The use of NGS for detecting copy-number alterations was also investigated. The workflow meets the sensitivity and specificity requirements for the genetic diagnosis of HBOCS and improves on the cost-effectiveness of current approaches.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Síndrome Hereditária de Câncer de Mama e Ovário/diagnóstico , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Algoritmos , Análise Custo-Benefício , DNA de Neoplasias/química , DNA de Neoplasias/genética , Feminino , Testes Genéticos/economia , Testes Genéticos/métodos , Humanos , Mutação , Reação em Cadeia da Polimerase , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
10.
Eur J Hum Genet ; 20(12): 1256-64, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22763379

RESUMO

Recently, constitutional MLH1 epimutations have been identified in a subset of Lynch syndrome (LS) cases. The aim of this study was the identification of patients harboring constitutional MLH1 epimutations in a set of 34 patients with a clinical suspicion of LS, MLH1-methylated tumors and non-detected germline mutations in mismatch repair (MMR) genes. MLH1 promoter methylation was analyzed in lymphocyte DNA samples by MS-MLPA (Methylation-specific multiplex ligation-dependent probe amplification). Confirmation of MLH1 constitutional methylation was performed by MS-MCA (Methylation-specific melting curve analysis), bisulfite sequencing and pyrosequencing in different biological samples. Allelic expression was determined using heterozygous polymorphisms. Vertical transmission was evaluated by MS-MLPA and haplotype analyses. MS-MLPA analysis detected constitutional MLH1 methylation in 2 of the 34 individuals whose colorectal cancers showed MLH1 methylation (5.9%). These results were confirmed by bisulfite-based methods. Both epimutation carriers had developed metachronous early-onset LS tumors, with no family history of LS-associated cancers in their first-degree relatives. In one of the cases, the identified MLH1 constitutional methylation was monoallelic and results in MLH1 and EPM2AIP1 allele-specific transcriptional silencing. It was present in normal somatic tissues and absent in spermatozoa. The methylated MLH1 allele was maternally transmitted and methylation was reversed in a daughter who inherited the same allele. MLH1 methylation screening in lymphocyte DNA from patients with early-onset MLH1-methylated LS-associated tumors allows the identification of epimutation carriers. The present study adds further evidence to the emerging entity of soma-wide MLH1 epimutation and its heritability.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Metilação de DNA , Triagem de Portadores Genéticos , Heterozigoto , Proteínas Nucleares/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Epigênese Genética , Feminino , Inativação Gênica , Mutação em Linhagem Germinativa , Haplótipos , Humanos , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL , Especificidade de Órgãos , Linhagem , Polimorfismo Genético , Análise de Sequência de DNA , Transcrição Genética
11.
Breast Cancer Res Treat ; 130(1): 341-4, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21761158

RESUMO

In this study, we present a novel complex rearrangement in the BRCA1 gene. The genomic rearrangement was identified using one of the two commercially available MLPA BRCA1 kits but was not confirmed with the other. In this report, we present the full characterization at the DNA and RNA levels of a new partial deletion of exon 20 of BRCA1. This is a complex deletion with four breakpoints which promotes aberrant splicing with partial deletion of exon 20 plus the insertion of a cryptic exon corresponding to a fragment of intron 20. The aberrant splicing generates an abnormal transcript with a frameshift that will result in a truncated BRCA1 protein.


Assuntos
Éxons , Genes BRCA1 , Neoplasias Ovarianas/genética , Deleção de Sequência , Adulto , Sequência de Bases , Feminino , Ordem dos Genes , Humanos , Dados de Sequência Molecular , Linhagem , Processamento de RNA , Alinhamento de Sequência
12.
Clin Chem ; 54(7): 1132-40, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18487285

RESUMO

BACKGROUND: approximately 20% of classic familial adenomatous polyposis (FAP) cases and 70% to 80% of attenuated FAP (AFAP) cases are negative for the APC/MUTYH point mutation. Quantitative multiplex PCR of short fluorescent fragments (QMPSF), a technique for detecting copy number alterations, has been successfully applied to several cancer syndrome genes. We used QMPSF for the APC gene to screen FAP APC/MUTYH mutation-negative families to improve their diagnostic surveillance. METHODS: we set up and validated APC-gene QMPSF using 23 negative and 1 positive control and examined 45 (13 FAP and 32 AFAP) unrelated members of APC/MUTYH mutation-negative families for copy number alterations. We confirmed the results using multiplex ligation-dependent probe amplification (MLPA). We used different approaches such as sequencing, quantitative real time-PCR (QRT-PCR), and fluorescence in situ hybridization (FISH) to further characterize the identified deletions. RESULTS: APC QMPSF was capable of detecting deletions with an acceptable variability, as shown by mean values (SD) of allele dosage for the deleted control obtained from intra- and interexperimental replicates [0.52 (0.05) and 0.45 (0.10)]. We detected 3 gross deletions in 13 (23%) of the classic FAP cases analyzed (1 complete gene deletion and 2 partial deletions encompassing exons 9 and 10 and exons 11-15, respectively). No rearrangements were detected in the 32 AFAP cases. CONCLUSIONS: QMPSF is able to detect rearrangements of the APC gene. Our findings highlight the importance of using a copy number alteration methodology as a first step in the routine genetic testing of FAP families in the clinical setting.


Assuntos
Proteína da Polipose Adenomatosa do Colo/genética , Corantes Fluorescentes , Deleção de Genes , Polipose Adenomatosa do Colo/genética , Sequência de Bases , DNA Glicosilases/genética , Éxons , Dosagem de Genes , Genes APC , Heterozigoto , Humanos , Hibridização in Situ Fluorescente , Dados de Sequência Molecular , Mutação Puntual , Reação em Cadeia da Polimerase/métodos
13.
Cancer Genet Cytogenet ; 158(1): 70-4, 2005 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-15771908

RESUMO

The incidence of familial adenomatous polyposis (FAP) is approximately 7.4 per 100,000 inhabitants. APC gene mutations have been found in 60-70% of all FAP families, codons 1309 (20%) and 1061 (8%) being known hot-spots. We searched for mutations in the APC gene in a population-based registry of FAP from the Spanish Balearic Islands. Fifty-one members of 12 FAP families registered in the Balearic Islands Cancer Registry were studied; three of them were de novo cases. Mutations in the APC gene were analyzed by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and sequencing. Haplotype was established by combining intra- and extragenic markers. Mutations in the APC gene were detected in 10 out of 12 (83%) families analyzed. Six families shared the same mutation, a 5-bp deletion at codon 1061 (c.3221_3225delACAAA). Five of the families containing this mutation shared the same haplotype and originated in the same geographic area. The codon 1061 mutation in the APC gene is the most common one in the Balearic Islands. Although this codon is a hot-spot, the haplotype analysis of these families is consistent for the presence of a founder effect of the 5-bp deletion at codon 1061 in FAP families in the Spanish Balearic Islands.


Assuntos
Polipose Adenomatosa do Colo/genética , Efeito Fundador , Mutação , Polipose Adenomatosa do Colo/epidemiologia , Feminino , Genes APC , Genótipo , Haplótipos , Humanos , Incidência , Masculino , Linhagem , Espanha/epidemiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA