RESUMO
BACKGROUND: Genetic-guided P2Y12 inhibitor selection has been proposed to reduce ischemic events by identifying CYP2C19 loss-of-function (LOF) carriers at increased risk with clopidogrel treatment after percutaneous coronary intervention (PCI). A prespecified analysis of TAILOR-PCI (Tailored Antiplatelet Therapy Following PCI) evaluated the effect of genetic-guided P2Y12 inhibitor therapy on cumulative ischemic and bleeding events. OBJECTIVES: Here, the authors detail a prespecified analysis of cumulative endpoints. The primary endpoint was cumulative incidence rate of ischemic events at 12 months. Cumulative incidence of major and minor bleeding was a secondary endpoint. Cox proportional hazards models as adapted by Wei, Lin, and Weissfeld were used to estimate the effect of this strategy on all observed events. METHODS: The TAILOR-PCI trial was a prospective trial including 5,302 post-PCI patients with acute and stable coronary artery disease (CAD) who were randomized to genetic-guided P2Y12 inhibitor or conventional clopidogrel therapy. In the genetic-guided group, LOF carriers were prescribed ticagrelor, whereas noncarriers received clopidogrel. TAILOR-PCI's primary analysis was time to first event in LOF carriers. RESULTS: Among 5,276 patients (median age 62 years; 25% women; 82% acute CAD; 18% stable CAD), 1,849 were LOF carriers (903 genetic-guided; 946 conventional therapy). The cumulative primary endpoint was significantly reduced in the genetic-guided group compared with the conventional therapy (HR: 0.61; 95% CI: 0.41-0.89; P = 0.011) with no significant difference in cumulative incidence of major or minor bleeding (HR: 1.36; 95% CI: 0.67-2.76; P = 0.39). CONCLUSIONS: Among CYP2C19 LOF carriers undergoing PCI, a genetic-guided strategy resulted in a statistically significant reduction in cumulative ischemic events without a significant difference in bleeding. (Tailored Antiplatelet Therapy Following PCI [TAILOR-PCI]; NCT01742117).
Assuntos
Síndrome Coronariana Aguda , Doença da Artéria Coronariana , Intervenção Coronária Percutânea , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Clopidogrel/efeitos adversos , Inibidores da Agregação Plaquetária/efeitos adversos , Citocromo P-450 CYP2C19/genética , Intervenção Coronária Percutânea/efeitos adversos , Estudos Prospectivos , Resultado do Tratamento , Hemorragia/etiologia , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/terapia , Doença da Artéria Coronariana/complicações , Síndrome Coronariana Aguda/terapia , Antagonistas do Receptor Purinérgico P2Y/efeitos adversosRESUMO
Pathogenic variants in COL1A1 and COL1A2 are involved in osteogenesis imperfecta (OI) and, rarely, Ehlers-Danlos syndrome (EDS) subtypes and OI-EDS overlap syndromes (OIEDS1 and OIEDS2, respectively). Here we describe a cohort of 34 individuals with likely pathogenic and pathogenic variants in COL1A1 and COL1A2, 15 of whom have potential OIEDS1 (n = 5) or OIEDS2 (n = 10). A predominant OI phenotype and COL1A1 frameshift variants are present in 4/5 cases with potential OIEDS1. On the other hand, 9/10 potential OIEDS2 cases have a predominant EDS phenotype, including four with an initial diagnosis of hypermobile EDS (hEDS). An additional case with a predominant EDS phenotype had a COL1A1 arginine-to-cysteine variant that was originally misclassified as a variant of uncertain significance despite this type of variant being associated with classical EDS with vascular fragility. Vascular/arterial fragility was observed in 4/15 individuals (including one individual with an original diagnosis of hEDS), which underscores the unique clinical surveillance and management needs in these patients. In comparison to previously described OIEDS1/2, we observed differentiating features that should be considered to refine currently proposed criteria for genetic testing in OIEDS, which will be beneficial for diagnosis and management. Additionally, these results highlight the importance of gene-specific knowledge for informed variant classification and point to a potential genetic resolution (COL1A2) for some cases of clinically diagnosed hEDS.
Assuntos
Síndrome de Ehlers-Danlos , Osteogênese Imperfeita , Humanos , Cadeia alfa 1 do Colágeno Tipo I , Mutação , Colágeno Tipo I/genética , Síndrome de Ehlers-Danlos/genética , Síndrome de Ehlers-Danlos/diagnóstico , Síndrome de Ehlers-Danlos/patologia , Osteogênese Imperfeita/diagnóstico , Osteogênese Imperfeita/genética , Osteogênese Imperfeita/patologia , FenótipoRESUMO
RATIONALE & OBJECTIVE: The etiology of kidney disease remains unknown in many individuals with chronic kidney disease (CKD). We created the Mayo Clinic Nephrology Genomics Clinic to improve our ability to integrate genomic and clinical data to identify the etiology of unexplained CKD. STUDY DESIGN: Retrospective study. SETTING & PARTICIPANTS: An essential component of our program is the Nephrology Genomics Board which consists of nephrologists, geneticists, pathologists, translational omics scientists, and trainees who interpret the patient's clinical and genetic data. Since September 2016, the Board has reviewed 163 cases (15 cystic, 100 glomerular, 6 congenital anomalies of kidney and urinary tract (CAKUT), 20 stones, 15 tubulointerstitial, and 13 other). ANALYTICAL APPROACH: Testing was performed with targeted panels, single gene analysis, or analysis of kidney-related genes from exome sequencing. Variant classification was obtained based on the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines. RESULTS: A definitive genetic diagnosis was achieved for 50 families (30.7%). The highest diagnostic yield was obtained in individuals with tubulointerstitial diseases (53.3%), followed by congenital anomalies of the kidney and urological tract (33.3%), glomerular (31%), cysts (26.7%), stones (25%), and others (15.4%). A further 20 (12.3%) patients had variants of interest, and variant segregation, and research activities (exome, genome, or transcriptome sequencing) are ongoing for 44 (40%) unresolved families. LIMITATIONS: Possible overestimation of diagnostic rate due to inclusion of individuals with variants with evidence of pathogenicity but classified as of uncertain significance by the clinical laboratory. CONCLUSIONS: Integration of genomic and research testing and multidisciplinary evaluation in a nephrology cohort with CKD of unknown etiology or suspected monogenic disease provided a diagnosis in a third of families. These diagnoses had prognostic implications, and often changes in management were implemented.
RESUMO
Gene-specific knowledge can enhance genetic variant classification, but may not be routinely incorporated into clinical laboratory practice. For example, FBN1 variants associated with Marfan syndrome may be variably classified depending on knowledge of FBN1-specific critical regions. In order to assess variability in classification of FBN1 variants, 674 FBN1 missense variants from 18 ClinVar submitters were compared and reanalyzed using FBN1-specific criteria and ACMG/AMP 2015 guidelines for variant interpretation. Conflicting variant classifications occurred in 30.7% of the missense variants that had multiple submitters. There were 451 classifications of 361 critical residue missense variants, with 80.0% (361/451) classified as likely pathogenic or pathogenic [(L)P]. Non-cysteine critical residue variants were less likely to be classified as (L)P [55.3% (78/141)] than cysteine variants [91.3% (283/310)] and were more likely to lack evidence citing the functional significance of the amino acid impacted. Application of FBN1-specific knowledge allowed for reclassification or discrepancy resolution in 65/361 (18.0%) critical residue variants. There were 522 classifications of 313 unique missense variants not known to impact a critical residue. Of these, 31.6% (165/522) were likely overclassified as either (L)P or uncertain significance (VUS), especially when minor allele frequency (MAF) was taken into account, and we reclassified or resolved classification discrepancies in 128/313 (40.9%) of these variants. Our results provide a refined framework and resource for FBN1 variant classification, and further supports the more global implications of combining gene-based knowledge with ACMG/AMP criteria and appropriate MAF cutoffs for variant classification that extend beyond FBN1.
Assuntos
Bases de Dados Genéticas , Fibrilina-1/genética , Estudos de Associação Genética/métodos , Predisposição Genética para Doença , Variação Genética , Alelos , Sequência de Aminoácidos , Sítios de Ligação , Cálcio/metabolismo , Fibrilina-1/química , Frequência do Gene , Genótipo , Humanos , Mutação de Sentido Incorreto , Ligação Proteica , Domínios e Motivos de Interação entre ProteínasRESUMO
Common genetic variation in CYP2C19 (cytochrome P450, family 2, subfamily C, polypeptide 19) *2 and *3 alleles leads to a loss of functional protein, and carriers of these loss-of-function alleles when treated with clopidogrel have significantly reduced clopidogrel active metabolite levels and high on-treatment platelet reactivity resulting in increased risk of major adverse cardiovascular events, especially after percutaneous coronary intervention. The Food and Drug Administration has issued a black box warning advising practitioners to consider alternative treatment in CYP2C19 poor metabolizers who might receive clopidogrel and to identify such patients by genotyping. However, routine clinical use of genotyping for CYP2C19 loss-of-function alleles in patients undergoing percutaneous coronary intervention is not recommended by clinical guidelines because of lack of prospective evidence. To address this critical gap, TAILOR-PCI (Tailored Antiplatelet Initiation to Lessen Outcomes due to Decreased Clopidogrel Response After Percutaneous Coronary Intervention) is a large, pragmatic, randomized trial comparing point-of-care genotype-guided antiplatelet therapy with routine care to determine whether identifying CYP2C19 loss-of-function allele patients prospectively and prescribing alternative antiplatelet therapy is beneficial.
Assuntos
Clopidogrel/farmacocinética , Citocromo P-450 CYP2C19/genética , Resistência a Medicamentos , Variantes Farmacogenômicos , Inibidores da Agregação Plaquetária/farmacocinética , Agregação Plaquetária/efeitos dos fármacos , Antagonistas do Receptor Purinérgico P2Y/farmacocinética , Tomada de Decisão Clínica , Clopidogrel/administração & dosagem , Clopidogrel/efeitos adversos , Citocromo P-450 CYP2C19/metabolismo , Rotulagem de Medicamentos , Genótipo , Humanos , Seleção de Pacientes , Fenótipo , Inibidores da Agregação Plaquetária/administração & dosagem , Inibidores da Agregação Plaquetária/efeitos adversos , Antagonistas do Receptor Purinérgico P2Y/administração & dosagem , Antagonistas do Receptor Purinérgico P2Y/efeitos adversos , Medição de RiscoRESUMO
Objective- Ceramides are sphingolipids involved with cellular signaling. Synthesis of ceramides occurs in all tissues. Ceramides accumulate within tissues and the blood plasma during metabolic dysfunction, dyslipidemia, and inflammation. Elevations of ceramides are predictive of cardiovascular mortality. We sought to verify the utility of plasma concentrations of 4 ceramides: N-palmitoyl-sphingosine [Cer(16:0)], N-stearoyl-sphingosine [Cer(18:0)], N-nervonoyl-sphingosine [Cer(24:1)], and N-lignoceroyl-sphingosine [Cer(24:0)] in predicting major adverse cardiovascular events in a diverse patient population referred for coronary angiography. Approach and Results- Plasma ceramides were measured in 495 participants before nonurgent coronary angiography. Coronary artery disease, defined as >50% stenosis in ≥1 coronary artery, was identified 265 (54%) cases. Ceramides were not significantly associated with coronary artery disease. Patients were followed for a combined primary end point of myocardial infarction, percutaneous intervention, coronary artery bypass, stroke, or death within 4 years. Ceramides were significantly predictive of outcomes after adjusting for age, sex, body mass index, hypertension, smoking, LDL (low-density lipoprotein) cholesterol, HDL (high-density lipoprotein) cholesterol, triglycerides, serum glucose, and family history of coronary artery disease. The fully adjusted per SD hazard ratios (95% confidence interval) were 1.50 (1.16-1.93) for Cer(16:0), 1.42 (1.11-1.83) for Cer(18:0), 1.43 (1.08-1.89) for Cer(24:1), and 1.58 (1.22-2.04) for the ceramide risk score. Conclusions- Elevated plasma concentrations of ceramides are independently associated with major adverse cardiovascular events in patients with and without coronary artery disease.
Assuntos
Ceramidas/sangue , Angiografia Coronária , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/diagnóstico por imagem , Estenose Coronária/sangue , Estenose Coronária/diagnóstico por imagem , Idoso , Biomarcadores/sangue , Ponte de Artéria Coronária/efeitos adversos , Ponte de Artéria Coronária/mortalidade , Doença da Artéria Coronariana/mortalidade , Doença da Artéria Coronariana/cirurgia , Estenose Coronária/mortalidade , Estenose Coronária/cirurgia , Progressão da Doença , Feminino , Humanos , Incidência , Masculino , Metabolômica/métodos , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Infarto do Miocárdio/epidemiologia , Intervenção Coronária Percutânea/efeitos adversos , Intervenção Coronária Percutânea/mortalidade , Valor Preditivo dos Testes , Prognóstico , Medição de Risco , Fatores de Risco , Acidente Vascular Cerebral/sangue , Acidente Vascular Cerebral/epidemiologia , Fatores de Tempo , Regulação para CimaRESUMO
Knowledge of variant pathogenicity is key to implementing genomic medicine. We describe variability between expert reviewers in assigning pathogenicity to sequence variants in LDLR, the causal gene in the majority of cases of familial hypercholesterolemia. LDLR was sequenced on the Illumina HiSeq platform (average read depth >200 × ) in 1013 Mayo Biobank participants recruited from 2012 to 2013. Variants with a minor allele frequency (MAF) <5% predicted to be functional or referenced in HGMD (Human Gene Mutation Database) or NCBI-ClinVar databases were reviewed. To assign pathogenicity, variant frequency in population data sets, computational predictions, reported observations and patient-level data including electronic health record-based post hoc phenotyping were leveraged. Of 178 LDLR variants passing quality control, 25 were selected for independent review using either an in-house protocol or a disease/gene-specific semi-quantitative framework based on the American College of Medical Genetics and Genomics-recommended lines of evidence. NCBI-ClinVar included interpretations for all queried variants with 74% (14/19) of variants with >1 submitter showing inconsistency in classification and 26% (5/19) appearing with conflicting clinical actionability. The discordance rate (one-step level of disagreement out of five classes in variant interpretation) between the reviewers was 40% (10/25). Two LDLR variants were independently deemed clinically actionable and returnable. Interpretation of LDLR variants was often discordant among ClinVar submitters and between expert reviewers. A quantitative approach based on strength of each predefined criterion in the context of specific genes and phenotypes may yield greater consistency between different reviewers.
Assuntos
Bases de Dados Genéticas/normas , Registros Eletrônicos de Saúde/normas , Testes Genéticos/normas , Hiperlipoproteinemia Tipo II/genética , Receptores de LDL/genética , Idoso , Feminino , Frequência do Gene , Humanos , Hiperlipoproteinemia Tipo II/diagnóstico , Achados Incidentais , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Polimorfismo GenéticoRESUMO
PURPOSE: Marfan syndrome is a systemic disorder that typically involves FBN1 mutations and cardiovascular manifestations. We investigated FBN1 genotype-phenotype correlations with aortic events (aortic dissection and prophylactic aortic surgery) in patients with Marfan syndrome. METHODS: Genotype and phenotype information from probands (n = 179) with an FBN1 pathogenic or likely pathogenic variant were assessed. RESULTS: A higher frequency of truncating or splicing FBN1 variants was observed in Ghent criteria-positive patients with an aortic event (n = 34) as compared with all other probands (n = 145) without a reported aortic event (79 vs. 39%; P < 0.0001), as well as Ghent criteria-positive probands (n = 54) without an aortic event (79 vs. 48%; P = 0.0039). Most probands with an early aortic event had a truncating or splicing variant (100% (n = 12) and 95% (n = 21) of patients younger than 30 and 40 years old, respectively). Aortic events occurred at a younger median age in patients with truncating/splicing variants (29 years) as compared with those with missense variants (51 years). A trend toward a higher frequency of truncating/splicing variants in patients with aortic dissection (n = 21) versus prophylactic surgery (n = 13) (85.7 vs. 69.3%; not significant) was observed. CONCLUSION: These aortic event- and age-associated findings may have important implications for the management of Marfan syndrome patients with FBN1 truncating and splicing variants.Genet Med 17 3, 177-187.
Assuntos
Processamento Alternativo , Aorta/cirurgia , Síndrome de Marfan/genética , Síndrome de Marfan/patologia , Proteínas dos Microfilamentos/genética , Adolescente , Adulto , Negro ou Afro-Americano/genética , Idoso , Aorta/patologia , Árabes/genética , Feminino , Fibrilina-1 , Fibrilinas , Humanos , Masculino , Síndrome de Marfan/etnologia , Síndrome de Marfan/cirurgia , Pessoa de Meia-Idade , Mutação , População Branca/genética , Adulto JovemRESUMO
OBJECTIVE: Familial hypercholesterolemia (FH) can be due to mutations in LDLR, PCSK9, and APOB. In phenotypically defined patients, a subset remains unresponsive to lipid-lowering therapies and requires low density-lipoprotein (LDL) apheresis treatment. In this pilot study, we examined the genotype/phenotype relationship in patients with dyslipidemia undergoing routine LDL apheresis. DESIGN: LDLR, APOB, and PCKS9 were analyzed for disease-causing mutations in seven patients undergoing routine LDL apheresis. Plasma and serum specimens were collected pre- and post-apheresis and analyzed for lipid concentrations, Lp(a) cholesterol, and lipoprotein particle concentrations (via NMR). RESULTS: We found that four patients harbored LDLR mutations and of these, three presented with xanthomas. While similar reductions in LDL-cholesterol (LDL-C), apolipoprotein B, and LDL particles (LDL-P) were observed following apheresis in all patients, lipid profile analysis revealed the LDLR mutation-positive cohort had a more pro-atherogenic profile (higher LDL-C, apolipoprotein B, LDL-P, and small LDL-P) pre-apheresis. CONCLUSION: Our data show that not all clinically diagnosed FH patients who require routine apheresis have genetically defined disease. In our small cohort, those with LDLR mutations had a more proatherogenic phenotype than those without identifiable mutations. This pilot cohort suggests that patients receiving the maximum lipid lowering therapy could be further stratified, based on genetic make-up, to optimize treatment.
Assuntos
Remoção de Componentes Sanguíneos , LDL-Colesterol/isolamento & purificação , Hiperlipoproteinemia Tipo II/terapia , Idoso , Idoso de 80 Anos ou mais , LDL-Colesterol/sangue , Feminino , Humanos , Hiperlipoproteinemia Tipo II/sangue , Hiperlipoproteinemia Tipo II/genética , Lipoproteína(a)/sangue , Masculino , Pessoa de Meia-Idade , Mutação , Receptores de LDL/genéticaRESUMO
Long QT syndrome (LQTS) is a cardiac channelopathy associated with syncope, seizures, and sudden death. Approximately 75% of LQTS is due to mutations in genes encoding for 3 cardiac ion channel α-subunits (LQT1 to LQT3). However, traditional mutational analyses have limited detection capabilities for atypical mutations such as large gene rearrangements. We set out to determine the prevalence and spectrum of large deletions/duplications in the major LQTS-susceptibility genes in unrelated patients who were mutation negative after point mutation analysis of LQT1- to LQT12-susceptibility genes. Forty-two unrelated, clinically strong LQTS patients were analyzed using multiplex ligation-dependent probe amplification, a quantitative fluorescent technique for detecting multiple exon deletions and duplications. The SALSA multiplex ligation-dependent probe amplification LQTS kit from MRC-Holland was used to analyze the 3 major LQTS-associated genes, KCNQ1, KCNH2, and SCN5A, and the 2 minor genes, KCNE1 and KCNE2. Overall, 2 gene rearrangements were found in 2 of 42 unrelated patients (4.8%, confidence interval 1.7 to 11). A deletion of KCNQ1 exon 3 was identified in a 10-year-old Caucasian boy with a corrected QT duration of 660 ms, a personal history of exercise-induced syncope, and a family history of syncope. A deletion of KCNQ1 exon 7 was identified in a 17-year-old Caucasian girl with a corrected QT duration of 480 ms, a personal history of exercise-induced syncope, and a family history of sudden cardiac death. In conclusion, because nearly 5% of patients with genetically elusive LQTS had large genomic rearrangements involving the canonical LQTS-susceptibility genes, reflex genetic testing to investigate genomic rearrangements may be of clinical value.
Assuntos
Sequência de Bases , Canais de Potássio Éter-A-Go-Go/genética , Duplicação Gênica , Predisposição Genética para Doença , Canal de Potássio KCNQ1/genética , Síndrome do QT Longo/genética , Deleção de Sequência , Adolescente , Criança , Canal de Potássio ERG1 , Feminino , Testes Genéticos/métodos , Genótipo , História Antiga , Humanos , Síndrome do QT Longo/sangue , Síndrome do QT Longo/diagnóstico , Masculino , Linhagem , Prevalência , Prognóstico , Adulto JovemRESUMO
The response to beta blockers in patients with heart failure could be associated with the genotype of drug-metabolizing enzymes and/or drug targets. The purpose of the present study was to determine whether specific genetic polymorphisms in ADRB1 (encoding the beta1-adrenergic receptor), CYP2D6, and UGT1A1 correlated with dose of, or response to, metoprolol or carvedilol treatment in patients with heart failure. A cohort of patients with heart failure (n = 93), characterized as responders or nonresponders to metoprolol (n = 19) or carvedilol (n = 74) therapy, was retrospectively identified. Individual genotyping was performed for a panel of polymorphisms in the ADRB1, CYP2D6, and UGT1A1 genes. Univariate and multivariate analyses were performed to compare the genotype to the metoprolol or carvedilol response status and dose. A nonresponse was identified in 10 of 19 patients taking metoprolol and 32 of 74 patients taking carvedilol. None of the polymorphisms in ADRB1, CYP2D6, and UGT1A1 were associated with a response or nonresponse. However, a significant relation between the carvedilol (but not metoprolol) dose and the ADRB1 and CYP2D6 genotype was observed. Patients homozygous for the ADRB1 389Gly variant or who were CYP2D6 poor metabolizers achieved a significantly higher dose of carvedilol (p = 0.01 and p = 0.02, respectively). In conclusion, polymorphisms in ADRB1, CYP2D6, and UGT1A1 were not associated with a response to metoprolol or carvedilol therapy in our cohort of patients with heart failure. The ADRB1 and CYP2D6 genotype, alone and in haplotype, were significantly associated with the dose of carvedilol.
Assuntos
Antagonistas Adrenérgicos beta/administração & dosagem , Carbazóis/administração & dosagem , Citocromo P-450 CYP2D6/genética , Glucuronosiltransferase/genética , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/genética , Metoprolol/administração & dosagem , Polimorfismo Genético , Propanolaminas/administração & dosagem , Receptores Adrenérgicos beta 1/genética , Idoso , Alelos , Carvedilol , Doença Crônica , Comorbidade , Genótipo , Haplótipos , Insuficiência Cardíaca/terapia , Humanos , Modelos Lineares , Pessoa de Meia-Idade , Fenótipo , Reação em Cadeia da Polimerase , Resultado do TratamentoRESUMO
Familial hypercholesterolemia (FH) is the most common form of autosomal-dominant hypercholesterolemia, and is caused by mutations in the low-density lipoprotein receptor (LDLR) gene. Heterozygous FH is characterized by elevated low-density lipoprotein (LDL) cholesterol and early-onset cardiovascular disease, whereas homozygous FH results in more severe LDL cholesterol elevation with death by 20 years of age. We present here the case of an African-American female FH patient presenting with a myocardial infarction at the age of 48, recurrent angina pectoris and numerous coronary artery stents. Her pretreated LDL cholesterol levels were more typical of a homozygous FH pattern and she was resistant to conventional lipid-lowering treatment, yet her other clinical parameters were not necessarily consistent with homozygous FH. Genetic testing revealed two LDLR variants on the same chromosome: one a novel missense mutation in exon 14 (Cys681Gly) and the other a promoter variant (IVS1-217C>T) previously shown to result in increased LDLR transcription. Disease-associated PCSK9 or APOB mutations were not identified in this individual. Overall, her genetic and clinical profile suggests that enhanced expression of the mutant LDLR allele resulted in a severe phenotype with characteristics of both heterozygous and homozygous FH.
Assuntos
Hiperlipoproteinemia Tipo II/genética , Mutação , Regiões Promotoras Genéticas , Receptores de LDL/genética , Apolipoproteínas B/genética , Colesterol/sangue , LDL-Colesterol/sangue , Éxons , Feminino , Rearranjo Gênico , Humanos , Hiperlipoproteinemia Tipo II/sangue , Hiperlipoproteinemia Tipo II/tratamento farmacológico , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Fenótipo , Pró-Proteína Convertase 9 , Pró-Proteína Convertases , Análise de Sequência de DNA , Serina Endopeptidases/genética , Regulação para CimaRESUMO
MUTYH adenomatous polyposis (MAP) can mimic both the familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC) phenotypes. As a result of MAP's phenotypic overlap with FAP, some DNA diagnostic laboratories perform MUTYH testing in conjunction with APC testing in patients with suspected FAP or attenuated FAP (AFAP). In addition to testing FAP/AFAP samples for MUTYH mutations, we were interested whether there would also be value in testing samples referred for HNPCC testing. To determine this, we tested a consecutive series of 229 samples referred for HNPCC testing for the two most common MUTYH mutations in the Caucasian population. To enrich our study population with MAP cases, we only included samples from patients with early onset colorectal cancer (CRC diagnosed <50 years old) in whom HNPCC had been excluded by microsatellite instability testing (microsatellite stable or low microsatellite instability). Four biallelic (2%) and six monoallelic (3%) MUTYH mutation carriers were identified. No clinical factors predicted MUTYH mutation status. Specifically, a family history of vertical transmission of CRC or having few polyps (<15) did not rule out the possibility of biallelic MUTYH mutations. Thus, MUTYH mutation testing may be a reasonable cascade test in early onset CRC found to have proficient DNA mismatch repair, regardless of pattern of family history or number of polyps.
Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/genética , DNA Glicosilases/genética , Adulto , Idade de Início , Neoplasias Colorretais Hereditárias sem Polipose/genética , Análise Mutacional de DNA , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , SíndromeRESUMO
PURPOSE: Production of reactive oxygen species (ROS) during chronic inflammation has been implicated in the progression of liver diseases and carcinogenesis. Subjects with inflammatory liver disease and one non-functional allele of the base excision repair gene, MYH, may be more susceptible to progression to cancer due to MYH haploinsufficiency in repairing oxidative damage caused by ROS. Here, we investigated the association of two common germline MYH mutations in patients with hepatocellular carcinoma (HCC) and cholangiocarcinoma. METHODS: DNA from patients with HCC (n=48) or cholangiocarcinoma (n=84) compared to non-cancerous controls (n=308) were genotyped for the Y165C and G382D mutations in MYH. RESULTS: There was no significant difference in MYH mutation carrier status between patients with HCC (1/48), cholangiocarcinoma (3/84), and non-cancerous controls (4/308). CONCLUSIONS: Patients with HCC or cholangiocarcinoma do not have an increased incidence of monoallelic MYH mutations pre-disposing them to disease.
Assuntos
Neoplasias dos Ductos Biliares/genética , Ductos Biliares Intra-Hepáticos/patologia , Carcinoma Hepatocelular/genética , Colangiocarcinoma/genética , DNA Glicosilases/genética , Neoplasias Hepáticas/genética , Análise Mutacional de DNA , Reparo do DNA , Predisposição Genética para Doença , Humanos , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de RestriçãoRESUMO
BACKGROUND & AIMS: A significant proportion of Lynch syndrome cases are believed to be due to large genomic alterations in the mismatch repair genes hMLH1 and hMSH2. However, previous studies have not adequately identified the frequency and scope of such mutations, and routine clinical Lynch syndrome testing often does not include analysis for these mutations. Our aim was to characterize hMLH1 and hMSH2 genomic rearrangements in a large population of suspected Lynch syndrome patients. METHODS: A total of 365 samples from probands referred for genetic testing for Lynch syndrome were analyzed for the presence of large genomic alterations in hMLH1 or hMSH2 by using a combination of techniques. Samples with a deletion in exons 1-6 in hMSH2 were further characterized by polymerase chain reaction to establish the presence of the hMSH2 American founder deletion. RESULTS: An hMLH1 or hMSH2 mutation was identified in 153 cases, and, of these, 12 of 67 (17.9%) and 39 of 86 (45.3%) had a large genomic alteration in hMLH1 and hMSH2, respectively. Overall, 6 different hMLH1 and 12 different hMSH2 deletions/duplications, including 10 novel mutations, were identified. Analysis of the hMSH2 exon 1-6 deletion samples showed that 13 of 18 (72.2%) had the American founder deletion. CONCLUSIONS: These data show a high frequency and diverse spectrum of large genomic alterations in hMLH1 and hMSH2 in suspected Lynch syndrome patients. Thus, a comprehensive mutation identification strategy that includes the ability to detect large genomic rearrangements is imperative for the clinical genetic identification of Lynch syndrome patients and families.
Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Proteínas de Ligação a DNA/genética , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Adaptadoras de Transdução de Sinal , Idade de Início , Proteínas de Transporte , Éxons , Feminino , Dosagem de Genes , Humanos , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL , Proteína 2 Homóloga a MutS , Núcleo Familiar , Regiões Promotoras Genéticas , Estudos Retrospectivos , Deleção de SequênciaRESUMO
It is now generally recognized that a specific subset of those patients clinically defined as having hereditary non polyposis colon cancer (HNPCC) have germline mutations in any one of several genes involved in DNA mismatch repair (MMR). This important subset of HNPCC families is now defined as having Lynch syndrome. A considerable amount of data has shown that tumors from patients with Lynch syndrome have characteristic features resulting from the underlying molecular involvement of defective MMR, that is, the presence of microsatellite instability (MSI) and the absence of MMR protein expression by immunohistochemistry (IHC). As a result, identifying patients with Lynch syndrome can now be accomplished by testing tumors for these tumor-related changes. Together, MSI and IHC are powerful tools that help identify individuals at risk for having Lynch syndrome and to distinguish these cases from HNPCC cases with other hereditary gene defects. Furthermore, IHC analysis provides valuable clues as to which MMR gene is mutated, allowing for comprehensive mutational analyses of that gene. Here, we discuss the current and historical perspectives regarding MSI and IHC analyses in tumors from sporadic colon cancer and from patients with Lynch syndrome. Given this background, we also provide a testing strategy for the identification of patients at risk for Lynch syndrome and subsequent gene testing.
Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/genética , Técnicas Imunoenzimáticas , Repetições de Microssatélites/genética , Pareamento Incorreto de Bases , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Instabilidade Genômica , Humanos , Fatores de RiscoRESUMO
A significant fraction of hereditary nonpolyposis colorectal cancer cases with defective mismatch repair (ie, Lynch syndrome) have large genomic deletions or duplications in the mismatch repair genes, hMLH1 and hMSH2, which can be challenging to detect by traditional methods. For this study, we developed and validated a novel Southern blot analysis method that allows for ascertainment of the extent of the dosage alterations on an exon-by-exon basis and compared this method to a second novel technique, multiplex ligation-dependent probe amplification (MLPA). From a total of 254 patients referred for Lynch syndrome testing, 20 of the 118 MLH1 cases and 42 of the 136 MSH2 cases had large genomic alterations, as detected by Southern blot. MLPA and Southern blot results were concordant with the exception of three major discrepancies: one because of a lack of MLPA probes for the region altered, another because of a point mutation near the MLPA probe ligation site, and another that was unexplained. Compared to Southern blot, MLPA has a shorter turn-around time, the analysis is less costly, less time-consuming, and less labor-intensive, and results are generally clear and unambiguous. However, concerns with MLPA include the presence of false-negatives and -positives because of positioning of probes and DNA variants near the probe ligation site. Overall, both Southern blot and MLPA provide important tools for the complete evaluation of patients with Lynch syndrome.
Assuntos
Southern Blotting/métodos , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Análise Mutacional de DNA/métodos , Dosagem de Genes , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Transporte , Neoplasias Colorretais Hereditárias sem Polipose/genética , DNA de Neoplasias/genética , Humanos , Proteína 1 Homóloga a MutL , Proteínas MutLRESUMO
BACKGROUND & AIMS: MYH-associated polyposis is a recently described disease that is characterized by multiple colorectal adenomas and a recessive pattern of inheritance. Individuals with MYH-associated polyposis have biallelic mutations in MYH, a base excision repair gene, and are negative for germline mutations in the APC gene. In this study, the 2 most prevalent MYH mutations in white persons, Y165C and G382D, were analyzed for their presence in 984 subjects selected from 3 groups: 400 undergoing screening colonoscopy and found to have 0-3 polyps, 444 with colorectal cancer (CRC), and 140 referred for APC mutation analysis in which a germline mutation was not identified. METHODS: Genotyping for Y165C and G382D was performed by Pyrosequencing. RESULTS: Biallelic mutations for Y165C and/or G382D were not found in any of those undergoing screening colonoscopy with 0-3 polyps (n = 400), in those APC-negative patients with <20 adenomatous polyps (n = 26), or in those with CRC who were older than 50 years (n = 328). Furthermore, these 2 MYH mutations were not found among patients whose tumors showed the presence of defective DNA mismatch repair (n = 62). However, the presence of biallelic germline MYH mutations correlated with the presence of >or=20 adenomatous polyps. Interestingly, 2 of the 116 individuals with CRC diagnosed at 50 years of age or younger also presented with biallelic germline mutations in MYH. CONCLUSIONS: These data suggest that screening of MYH should be considered not only in patients with multiple polyps but also in patients with early-onset CRC.
Assuntos
Polipose Adenomatosa do Colo/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , DNA Glicosilases/genética , Adulto , Idoso , Genes APC/fisiologia , Predisposição Genética para Doença , Genótipo , Mutação em Linhagem Germinativa/genética , Humanos , Pessoa de Meia-Idade , Análise de Sequência de DNARESUMO
Akt plays a pivotal role in cell survival and tumorigenesis. We investigated the potential interaction between sphingosine-1-phosphate (S1P) and platelet-derived growth factor (PDGF) in the Akt signaling pathway. Using mouse embryonic fibroblasts (MEFs) from S1P receptor knockout mice, we show here that S1P3 was required for S473 phosphorylation of Akt by S1P. In addition, S1P-stimulated activation of Akt, but not ERK, was blocked by a PDGF receptor (PDGFR)-specific inhibitor, AG1296, suggesting a S1P3-mediated specific crosstalk between the Akt signaling pathways of S1P and PDGFR in MEFs. We investigated this crosstalk under different conditions and found that both Akt and ERK activation induced by S1P, but not lysophosphatidic acid (LPA), in HEY ovarian cancer cells required PDGFR but not epidermal growth factor receptor (EGFR) or insulin-like growth factor-I receptor (IGFR). Importantly, S1P induced a Gi-dependent tyrosine phosphorylation of PDGFR in HEY cells. This dependence on PDGFR in S1P-induced Akt activation was also observed in A2780, T47D, and HMEC-1 cells (which express S1P3), but not in PC-3 or GI-101A cells (which do not express S1P3), further supporting that S1P3 mediates the crosstalk between S1P and PDGFR. This is the first report demonstrating a unique interaction between S1P3 and PDGFR, in addition to demonstrating a specific role for S1P3 in S1P-induced Akt activation.
Assuntos
Lisofosfolipídeos , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas/metabolismo , Receptores do Fator de Crescimento Derivado de Plaquetas/metabolismo , Esfingosina/análogos & derivados , Esfingosina/farmacologia , Animais , Linhagem Celular , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Feminino , Fibroblastos , Humanos , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Especificidade de Órgãos , Neoplasias Ovarianas/enzimologia , Neoplasias Ovarianas/metabolismo , Fosforilação/efeitos dos fármacos , Fosfotirosina/metabolismo , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais/efeitos dos fármacosRESUMO
Lysophospholipids (LPLs), including glycerol- and sphingoid-based lipids, stimulate cell signaling and play important pathophysiological roles in humans and other animals. These LPLs include lysophosphatidic acid (LPA), lysophosphatidylinositol (LPI), lysophosphatidylcholine (LPC), lysophosphatidylserine (LPS), sphingosine-1-phosphate (S1P), and sphingosylphosphorylcholine (SPC). Analyses of LPLs in human body fluids from subjects with different pathophysiological conditions reveal not only the relevance of LPLs in human diseases, but also their potential application as biomarkers and/or therapeutic targets. In recent years, the identification and/or characterization of the plasma membrane receptors for LPLs and enzymes regulating the metabolism of LPLs have greatly facilitated our understanding of their role and signaling properties. In vitro and in vivo functional and signaling studies have revealed the broad and potent biological effects of LPLs and the mechanisms of LPL actions in different cellular systems. Development of specific antagonists for each of the LPL receptors will provide powerful tools for dissecting signaling pathways mediated by receptor subtypes. More importantly, these antagonists may serve as therapeutics for relevant diseases. Genetic depletion of LPL receptors in mice has provided and will continue to provide critical information on the pathophysiological roles of LPL receptors. It is important to further evaluate the significance of targeting these bioactive LPL receptors, their downstream signaling molecules, and/or metabolic enzymes in the treatment of cancers and other diseases.