RESUMO
Considering polygenic risk scores (PRSs) in individual risk prediction is increasingly implemented in genetic testing for hereditary breast cancer (BC) based on next-generation sequencing (NGS). To calculate individual BC risks, the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) with the inclusion of the BCAC 313 or the BRIDGES 306 BC PRS is commonly used. The PRS calculation depends on accurately reproducing the variant allele frequencies (AFs) and, consequently, the distribution of PRS values anticipated by the algorithm. Here, the 324 loci of the BCAC 313 and the BRIDGES 306 BC PRS were examined in population-specific database gnomAD and in real-world data sets of five centers of the German Consortium for Hereditary Breast and Ovarian Cancer (GC-HBOC), to determine whether these expected AFs can be reproduced by NGS-based genotyping. Four PRS loci were non-existent in gnomAD v3.1.2 non-Finnish Europeans, further 24 loci showed noticeably deviating AFs. In real-world data, between 11 and 23 loci were reported with noticeably deviating AFs, and were shown to have effects on final risk prediction. Deviations depended on the sequencing approach, variant caller and calling mode (forced versus unforced) employed. Therefore, this study demonstrates the necessity to apply quality assurance not only in terms of sequencing coverage but also observed AFs in a sufficiently large cohort, when implementing PRSs in a routine diagnostic setting. Furthermore, future PRS design should be guided by the technical reproducibility of expected AFs across commonly used genotyping methods, especially NGS, in addition to the observed effect sizes.
Assuntos
Neoplasias da Mama , Herança Multifatorial , Humanos , Feminino , Neoplasias da Mama/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Sequenciamento de Nucleotídeos em Larga Escala/normas , Técnicas de Genotipagem/métodos , Técnicas de Genotipagem/normas , Predisposição Genética para Doença , Testes Genéticos/métodos , Testes Genéticos/normas , Frequência do Gene , Algoritmos , Estratificação de Risco GenéticoRESUMO
BACKGROUND: Truncating pathogenic or likely pathogenic variants of CDH1 cause hereditary diffuse gastric cancer (HDGC), a tumour risk syndrome that predisposes carrier individuals to diffuse gastric and lobular breast cancer. Rare CDH1 missense variants are often classified as variants of unknown significance. We conducted a genotype-phenotype analysis in families carrying rare CDH1 variants, comparing cancer spectrum in carriers of pathogenic or likely pathogenic variants (PV/LPV; analysed jointly) or missense variants of unknown significance, assessing the frequency of families with lobular breast cancer among PV/LPV carrier families, and testing the performance of lobular breast cancer-expanded criteria for CDH1 testing. METHODS: This genotype-first study used retrospective diagnostic and clinical data from 854 carriers of 398 rare CDH1 variants and 1021 relatives, irrespective of HDGC clinical criteria, from 29 institutions in ten member-countries of the European Reference Network on Tumour Risk Syndromes (ERN GENTURIS). Data were collected from Oct 1, 2018, to Sept 20, 2022. Variants were classified by molecular type and clinical actionability with the American College of Medical Genetics and Association for Molecular Pathology CDH1 guidelines (version 2). Families were categorised by whether they fulfilled the 2015 and 2020 HDGC clinical criteria. Genotype-phenotype associations were analysed by Student's t test, Kruskal-Wallis, χ2, and multivariable logistic regression models. Performance of HDGC clinical criteria sets were assessed with an equivalence test and Youden index, and the areas under the receiver operating characteristic curves were compared by Z test. FINDINGS: From 1971 phenotypes (contributed by 854 probands and 1021 relatives aged 1-93 years), 460 had gastric and breast cancer histology available. CDH1 truncating PV/LPVs occurred in 176 (21%) of 854 families and missense variants of unknown significance in 169 (20%) families. Multivariable logistic regression comparing phenotypes occurring in families carrying PV/LPVs or missense variants of unknown significance showed that lobular breast cancer had the greatest positive association with the presence of PV/LPVs (odds ratio 12·39 [95% CI 2·66-57·74], p=0·0014), followed by diffuse gastric cancer (8·00 [2·18-29·39], p=0·0017) and gastric cancer (7·81 [2·03-29·96], p=0·0027). 136 (77%) of 176 families carrying PV/LPVs fulfilled the 2015 HDGC criteria. Of the remaining 40 (23%) families, who did not fulfil the 2015 criteria, 11 fulfilled the 2020 HDGC criteria, and 18 had lobular breast cancer only or lobular breast cancer and gastric cancer, but did not meet the 2020 criteria. No specific CDH1 variant was found to predispose individuals specifically to lobular breast cancer, although 12 (7%) of 176 PV/LPV carrier families had lobular breast cancer only. Addition of three new lobular breast cancer-centred criteria improved testing sensitivity while retaining high specificity. The probability of finding CDH1 PV/LPVs in patients fulfilling the lobular breast cancer-expanded criteria, compared with the 2020 criteria, increased significantly (AUC 0·92 vs 0·88; Z score 3·54; p=0·0004). INTERPRETATION: CDH1 PV/LPVs were positively associated with HDGC-related phenotypes (lobular breast cancer, diffuse gastric cancer, and gastric cancer), and no evidence for a positive association with these phenotypes was found for CDH1 missense variants of unknown significance. CDH1 PV/LPVs occurred often in families with lobular breast cancer who did not fulfil the 2020 HDGC criteria, supporting the expansion of lobular breast cancer-centred criteria. FUNDING: European Reference Network on Genetic Tumour Risk Syndromes, European Regional Development Fund, Fundação para a Ciência e a Tecnologia (Portugal), Cancer Research UK, and European Union's Horizon 2020 research and innovation programme.
Assuntos
Neoplasias da Mama , Carcinoma Lobular , Neoplasias Gástricas , Feminino , Humanos , Antígenos CD/genética , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Caderinas/genética , Predisposição Genética para Doença , Genótipo , Células Germinativas/patologia , Mutação em Linhagem Germinativa , Linhagem , Fenótipo , Estudos Retrospectivos , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/genética , Mutação de Sentido IncorretoRESUMO
Rare variants in at least 10 genes, including BRCA1, BRCA2, PALB2, ATM, and CHEK2, are associated with increased risk of breast cancer; however, these variants, in combination with common variants identified through genome-wide association studies, explain only a fraction of the familial aggregation of the disease. To identify further susceptibility genes, we performed a two-stage whole-exome sequencing study. In the discovery stage, samples from 1528 breast cancer cases enriched for breast cancer susceptibility and 3733 geographically matched unaffected controls were sequenced. Using five different filtering and gene prioritization strategies, 198 genes were selected for further validation. These genes, and a panel of 32 known or suspected breast cancer susceptibility genes, were assessed in a validation set of 6211 cases and 6019 controls for their association with risk of breast cancer overall, and by estrogen receptor (ER) disease subtypes, using gene burden tests applied to loss-of-function and rare missense variants. Twenty genes showed nominal evidence of association (p-value < 0.05) with either overall or subtype-specific breast cancer. Our study had the statistical power to detect susceptibility genes with effect sizes similar to ATM, CHEK2, and PALB2, however, it was underpowered to identify genes in which susceptibility variants are rarer or confer smaller effect sizes. Larger sample sizes would be required in order to identify such genes.
RESUMO
The evolutionary conserved Polo-like kinase 4 (PLK4) is essential for centriole duplication, spindle assembly, and de novo centriole formation. In man, homozygous mutations in PLK4 lead to primary microcephaly, altered PLK4 expression is associated with aneuploidy in human embryos. Here, we report on a consanguineous four-generation family with 8 affected individuals compound heterozygous for a novel missense variant, c.881 T > G, and a deletion of the PLK4 gene. The clinical phenotype of the adult patients is mild compared to individuals with previously described PLK4 mutations. One individual was homozygous for the variant c.881G and phenotypically unaffected. The deletion was inherited by 14 of 16 offspring and thus exhibits transmission ratio distortion (TRD). Moreover, based on the already published families with PLK4 mutations, it could be shown that due to the preferential transmission of the mutant alleles, the number of affected offspring is significantly increased. It is assumed that reduced expression of PLK4 decreases the intrinsically high error rate of the first cell divisions after fertilization, increases the number of viable embryos and thus leads to preferential transmission of the deleted/mutated alleles.
Assuntos
Proteínas de Ciclo Celular , Centríolos , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Divisão Celular , Centríolos/genética , Centríolos/metabolismo , Humanos , Mutação , Proteínas Serina-Treonina Quinases/genéticaRESUMO
[This corrects the article DOI: 10.1371/journal.pgen.1009679.].
RESUMO
Numerous genetic studies have established a role for rare genomic variants in Congenital Heart Disease (CHD) at the copy number variation (CNV) and de novo variant (DNV) level. To identify novel haploinsufficient CHD disease genes, we performed an integrative analysis of CNVs and DNVs identified in probands with CHD including cases with sporadic thoracic aortic aneurysm. We assembled CNV data from 7,958 cases and 14,082 controls and performed a gene-wise analysis of the burden of rare genomic deletions in cases versus controls. In addition, we performed variation rate testing for DNVs identified in 2,489 parent-offspring trios. Our analysis revealed 21 genes which were significantly affected by rare CNVs and/or DNVs in probands. Fourteen of these genes have previously been associated with CHD while the remaining genes (FEZ1, MYO16, ARID1B, NALCN, WAC, KDM5B and WHSC1) have only been associated in small cases series or show new associations with CHD. In addition, a systems level analysis revealed affected protein-protein interaction networks involved in Notch signaling pathway, heart morphogenesis, DNA repair and cilia/centrosome function. Taken together, this approach highlights the importance of re-analyzing existing datasets to strengthen disease association and identify novel disease genes and pathways.
Assuntos
Variações do Número de Cópias de DNA/genética , Haploinsuficiência/genética , Cardiopatias Congênitas/genética , Bases de Dados Genéticas , Expressão Gênica/genética , Perfilação da Expressão Gênica/métodos , Predisposição Genética para Doença/genética , Genômica/métodos , Humanos , Canais Iônicos/genética , Proteínas de Membrana/genética , Polimorfismo de Nucleotídeo Único/genética , Transcriptoma/genéticaRESUMO
Congenital hiatal hernia (HH) is a rare congenital defect and is often described on a sporadic basis, but familial cases have also been reported. The mechanism of development is not well understood, and to our knowledge no specific genetic factors have been implicated to date. We report on seven individuals from two families with 9q22 duplication, who have variably associated features including congenital HH in four individuals. One family had an 1.09 Mb 9q22 duplication, and the other family had an overlapping 2.73 Mb 9q22 duplication. We review the genes in this region and discuss BARX1 (BarH-like homeobox gene 1) as a gene of interest.
Assuntos
Duplicação Cromossômica , Cromossomos Humanos Par 9/genética , Hérnia Hiatal/patologia , Proteínas de Homeodomínio/genética , Mutação , Fatores de Transcrição/genética , Adolescente , Pré-Escolar , Feminino , Hérnia Hiatal/congênito , Hérnia Hiatal/genética , Humanos , Lactente , Recém-Nascido , Masculino , LinhagemRESUMO
[This corrects the article DOI: 10.1371/journal.pone.0201041.].
RESUMO
Bosch-Boonstra-Schaaf optic atrophy syndrome (BBSOAS) has been described as an autosomal-dominant disorder caused by mutations in the NR2F1 gene, whose common characteristics include developmental delay, intellectual disability, optic nerve atrophy, hypotonia, attention deficit disorder, autism spectrum disorder, seizures, hearing defects, spasticity and thinning of the corpus callosum. Missense mutations in NR2F1 have been reported to be the major cause of BBSOAS. A possible genotype-phenotype correlation has been considered with missense mutations affecting the ligand-binding domain of NR2F1 as well as whole-gene deletions of NR2F1 showing a milder phenotype of BBSOAS. Here we report on a patient with a novel frameshift mutation in NR2F1 showing the full spectrum of BBOAS indicating an expanded clinical spectrum and a reconsideration of the observed genotype-phenotype correlation.
Assuntos
Transtorno do Espectro Autista/genética , Fator I de Transcrição COUP/genética , Deficiência Intelectual/genética , Atrofias Ópticas Hereditárias/genética , Transtorno do Espectro Autista/diagnóstico por imagem , Transtorno do Espectro Autista/fisiopatologia , Sequência de Bases , Criança , Mutação da Fase de Leitura , Estudos de Associação Genética , Humanos , Deficiência Intelectual/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Hipotonia Muscular/genética , Mutação de Sentido Incorreto , Atrofias Ópticas Hereditárias/diagnóstico por imagem , Atrofias Ópticas Hereditárias/fisiopatologia , Fenótipo , Mutação Puntual , Convulsões/genéticaRESUMO
NKAP is a ubiquitously expressed nucleoplasmic protein that is currently known as a transcriptional regulatory molecule via its interaction with HDAC3 and spliceosomal proteins. Here, we report a disorder of transcriptional regulation due to missense mutations in the X chromosome gene, NKAP. These mutations are clustered in the C-terminal region of NKAP where NKAP interacts with HDAC3 and post-catalytic spliceosomal complex proteins. Consistent with a role for the C-terminal region of NKAP in embryogenesis, nkap mutant zebrafish with a C-terminally truncated NKAP demonstrate severe developmental defects. The clinical features of affected individuals are highly conserved and include developmental delay, hypotonia, joint contractures, behavioral abnormalities, Marfanoid habitus, and scoliosis. In affected cases, transcriptome analysis revealed the presence of a unique transcriptome signature, which is characterized by the downregulation of long genes with higher exon numbers. These observations indicate the critical role of NKAP in transcriptional regulation and demonstrate that perturbations of the C-terminal region lead to developmental defects in both humans and zebrafish.
Assuntos
Disfunção Cognitiva/genética , Mutação de Sentido Incorreto/genética , Proteínas Repressoras/genética , Transcrição Gênica/genética , Sequência de Aminoácidos , Animais , Regulação para Baixo/genética , Éxons/genética , Regulação da Expressão Gênica/genética , Genes Ligados ao Cromossomo X/genética , Histona Desacetilases/genética , Humanos , Alinhamento de Sequência , Transcriptoma/genética , Peixe-Zebra/genéticaRESUMO
Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumors with a strong hereditary background and a large genetic heterogeneity. Identification of the underlying genetic cause is crucial for the management of patients and their families as it aids differentiation between hereditary and sporadic cases. To improve diagnostics and clinical management we tailored an enrichment based comprehensive multi-gene next generation sequencing panel applicable to both analyses of tumor tissue and blood samples. We applied this panel to tumor samples and compared its performance to our current routine diagnostic approach. Routine diagnostic sequencing of 11 PPGL susceptibility genes was applied to blood samples of 65 unselected PPGL patients at a single center in Dresden, Germany. Predisposing germline mutations were identified in 19 (29.2%) patients. Analyses of 28 PPGL tumor tissues using the dedicated PPGL panel revealed pathogenic or likely pathogenic variants in known PPGL susceptibility genes in 21 (75%) cases, including mutations in IDH2, ATRX and HRAS. These mutations suggest sporadic tumor development. Our results imply a diagnostic benefit from extended molecular tumor testing of PPGLs and consequent improvement of patient management. The approach is promising for determination of prognostic biomarkers that support therapeutic decision-making.
RESUMO
Triple A syndrome, a multisystemic autosomal recessive disease, is characterized by the clinical triad of adrenal insufficiency, alacrima and achalasia in combination with progressive neurological impairments. The disorder is caused by homozygous or compound heterozygous mutations in the AAAS gene. Here we present the clinical and molecular data of a ten year old patient with triple A syndrome. Array CGH analysis confirmed the PCR-based assumption of a homozygous deletion of the entire AAAS gene in the patient and a heterozygous deletion in both parents. We demonstrate that the patient carries a 15â¯kb deletion and identified the 5' and 3' breakpoints outside the AAAS gene. This is the first report of a triple A syndrome patient with a homozygous deletion of the entire AAAS gene.
Assuntos
Insuficiência Adrenal/genética , Acalasia Esofágica/genética , Deleção de Genes , Proteínas do Tecido Nervoso/genética , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Insuficiência Adrenal/patologia , Adulto , Criança , Pré-Escolar , Acalasia Esofágica/patologia , Homozigoto , Humanos , Masculino , LinhagemRESUMO
Vitamin K antagonists (VKAs) have been used in 1% of the world's population for prophylaxis or treatment of thromboembolic events for 64 years. Impairment of osteoblast function and osteoporosis has been described in patients receiving VKAs. Given the involvement of cells of the bone marrow microenvironment (BMM), such as mesenchymal stem cells (MSCs) and macrophages, as well as other factors such as the extracellular matrix for the maintenance of normal hematopoietic stem cells (HSCs), we investigated a possible effect of VKAs on hematopoiesis via the BMM. Using various transplantation and in vitro assays, we show here that VKAs alter parameters of bone physiology and reduce functional HSCs 8-fold. We implicate impairment of the functional, secreted, vitamin K-dependent, γ-carboxylated form of periostin by macrophages and, to a lesser extent, MSCs of the BMM and integrin ß3-AKT signaling in HSCs as at least partly causative of this effect, with VKAs not being directly toxic to HSCs. In patients, VKA use associates with modestly reduced leukocyte and monocyte counts, albeit within the normal reference range. VKAs decrease human HSC engraftment in immunosuppressed mice. Following published examples that alteration of the BMM can lead to hematological malignancies in mice, we describe, without providing a causal link, that the odds of VKA use are higher in patients with vs without a diagnosis of myelodysplastic syndrome (MDS). These results demonstrate that VKA treatment impairs HSC function via impairment of the BMM and the periostin/integrin ß3 axis, possibly associating with increased MDS risk.
Assuntos
Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Microambiente Celular/efeitos dos fármacos , Hematopoese/efeitos dos fármacos , Vitamina K/antagonistas & inibidores , Animais , Anticoagulantes/farmacologia , Biomarcadores , Moléculas de Adesão Celular/metabolismo , Relação Dose-Resposta a Droga , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Leucócitos/imunologia , Leucócitos/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/etiologia , Síndromes Mielodisplásicas/metabolismo , Vitamina K/farmacologia , Varfarina/farmacologiaRESUMO
BACKGROUND: With the introduction of Olaparib treatment for BRCA-deficient recurrent ovarian cancer, testing for somatic and/or germline mutations in BRCA1/2 genes in tumor tissues became essential for treatment decisions. In most cases only formalin-fixed paraffin-embedded (FFPE) samples, containing fragmented and chemically modified DNA of minor quality, are available. Thus, multiplex PCR-based sequencing is most commonly applied in routine molecular testing, which is predominantly focused on the identification of known hot spot mutations in oncogenes. METHODS: We compared the overall performance of an adjusted targeted capture-based enrichment protocol and a multiplex PCR-based approach for calling of pathogenic SNVs and InDels using DNA extracted from 13 FFPE tissue samples. We further applied both strategies to seven blood samples and five matched FFPE tumor tissues of patients with known germline exon-spanning deletions and gene-wide duplications in BRCA1/2 to evaluate CNV detection based solely on panel NGS data. Finally, we analyzed DNA from FFPE tissues of 11 index patients from families suspected of having hereditary breast and ovarian cancer, of whom no blood samples were available for testing, in order to identify underlying pathogenic germline BRCA1/2 mutations. RESULTS: The multiplex PCR-based protocol produced inhomogeneous coverage among targets of each sample and between samples as well as sporadic amplicon drop out, leading to insufficiently or non-covered nucleotides, which subsequently hindered variant detection. This protocol further led to detection of PCR-artifacts that could easily have been misinterpreted as pathogenic mutations. No such limitations were observed by application of an adjusted targeted capture-based protocol, which allowed for CNV calling with 86% sensitivity and 100% specificity. All pathogenic CNVs were confirmed in the five matched FFPE tumor samples from patients carrying known pathogenic germline mutations and we additionally identified somatic loss of the second allele in BRCA1/2. Furthermore we detected pathogenic BRCA1/2 variants in four the eleven FFPE samples from patients of whom no blood was available for analysis. CONCLUSIONS: We demonstrate that an adjusted targeted capture-based enrichment protocol is superior to commonly applied multiplex PCR-based protocols for reliable BRCA1/2 variant detection, including CNV-detection, using FFPE tumor samples.
Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Mutação em Linhagem Germinativa , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Neoplasias Ovarianas/genética , Neoplasias da Mama/sangue , Neoplasias da Mama/diagnóstico , Variações do Número de Cópias de DNA/genética , Feminino , Formaldeído/química , Humanos , Mutação INDEL , Masculino , Reação em Cadeia da Polimerase Multiplex/métodos , Neoplasias Ovarianas/sangue , Neoplasias Ovarianas/diagnóstico , Inclusão em Parafina , Linhagem , Reprodutibilidade dos Testes , Fixação de TecidosRESUMO
Truncating mutations in the last and penultimate exons of the PPM1D gene were recently described as a cause for mild to severe intellectual disability in fourteen patients. Feeding difficulties, periods of fever and vomiting as well as a high pain threshold were described as additional characteristic features and the disorder was subsequently termed "intellectual developmental disorder with gastrointestinal difficulties and high pain threshold (IDDGIP)" in the OMIM database (MIM # 617450). Here we report on an additional patient carrying a novel de novo truncating mutation NM_003620.3: c.1535del, p.(Asn512Ilefs*2) in the last exon of PPM1D. While the patient showed features overlapping with the reported phenotype, such as a short stature and small hands and feet, he also presented with additional features like cleft lip and palate and an aberrant right subclavian artery. Notably, the patient did not have any gastrointestinal difficulties or periods of fever, indicating variability of the phenotype of patients with PPM1D mutations.
Assuntos
Anormalidades Múltiplas/genética , Gastroenteropatias/genética , Deficiência Intelectual/genética , Mutação , Limiar da Dor , Fenótipo , Proteína Fosfatase 2C/genética , Anormalidades Múltiplas/patologia , Criança , Gastroenteropatias/patologia , Humanos , Deficiência Intelectual/patologia , Masculino , SíndromeRESUMO
NGS-based multiple gene panel resequencing in combination with a high resolution CGH-array was used to identify genetic risk factors for hereditary breast and/or ovarian cancer in 237 high risk patients who were previously tested negative for pathogenic BRCA1/2 variants. All patients were screened for pathogenic variants in 94 different cancer predisposing genes. We identified 32 pathogenic variants in 14 different genes (ATM, BLM, BRCA1, CDH1, CHEK2, FANCG, FANCM, FH, HRAS, PALB2, PMS2, PTEN, RAD51C and NBN) in 30 patients (12.7%). Two pathogenic BRCA1 variants that were previously undetected due to less comprehensive and sensitive methods were found. Five pathogenic variants are novel, three of which occur in genes yet unrelated to hereditary breast and/or ovarian cancer (FANCG, FH and HRAS). In our cohort we discovered a remarkably high frequency of truncating variants in FANCM (2.1%), which has recently been suggested as a susceptibility gene for hereditary breast cancer. Two patients of our cohort carried two different pathogenic variants each and 10 other patients in whom a pathogenic variant was confirmed also harbored a variant of unknown significance in a breast and ovarian cancer susceptibility gene. We were able to identify pathogenic variants predisposing for tumor formation in 12.3% of BRCA1/2 negative breast and/or ovarian cancer patients.
Assuntos
Neoplasias da Mama Masculina/genética , Neoplasias da Mama/genética , DNA Helicases/genética , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Neoplasias Ovarianas/genética , Adolescente , Adulto , Idoso , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/patologia , Estudos de Coortes , Análise Mutacional de DNA , Feminino , Testes Genéticos , Humanos , Masculino , Anamnese , Pessoa de Meia-Idade , Adulto JovemRESUMO
BACKGROUND: In recent years, the number of patients being offered BRCA1/2 testing has changed dramatically. Advances in high-throughput sequencing technology have led many diagnostic laboratories to test next-generation sequencing (NGS)-based platforms as the main technology for clinical testing. As a consequence, the proportion of novel BRCA1/2 variants detected has greatly increased. Here, we describe two novel BRCA1 large deletions detected in Italian patients affected by hereditary breast and ovarian cancer syndrome (HBOC). METHODS: We applied an NGS pipeline with a reliable copy number variation (CNV) prediction algorithm. Successively, samples were investigated using the Multiplex Amplicon Quantification (MAQ) assay and array comparative genomic hybridization (CGH). In a single case, long-range polymerase chain reaction (PCR) was employed for careful detection of the breakpoint region, while the RepeatMasker program was used to identify Alu sequences at the junction point. RESULTS: A 137.8 kb deletion, involving the first six exons of BRCA1 and the full NBR2, BRCA1P1, NBR1, and TMEM106a genes, was detected in an Italian woman diagnosed with high-grade serous ovarian carcinoma. A second rearrangement, involving the deletion of BRCA1 11-14 exons, was detected in a breast cancer patient and was fully characterized and reported according to recommended Human Genome Variation Society (HGVS) nomenclature: NG_005905.2: g.125038_143266del; NM_007294.3: c.2817_4716del; NP_009225: p.Lys862Metfs? CONCLUSION: Although it was not possible to perform a familial segregation analysis and more direct evidence of the relationship between genotype and phenotype is necessary, both of the novel reported rearrangements cause the loss of crucial functional domains of the BRCA1 protein and this event supports their pathogenicity.
Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Neoplasias Ovarianas/genética , Idoso , Neoplasias da Mama/patologia , Feminino , Rearranjo Gênico/genética , Predisposição Genética para Doença , Genoma Humano/genética , Genômica/métodos , Síndrome Hereditária de Câncer de Mama e Ovário/patologia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Itália , Pessoa de Meia-IdadeRESUMO
Although intellectual disability is one of the major indications for genetic counselling, there are no homogenous diagnostic algorithms for molecular testing. While whole exome sequencing is increasingly applied, we questioned whether analyzing a partial exome, enriched for genes associated with Mendelian disorders, might be a valid alternative approach that yields similar detection rates but requires less sequencing capacities. Within this context 106 patients with different intellectual disability forms were analyzed for mutations in 4.813 genes after pre-exclusion of copy number variations by array-CGH. Subsequent variant interpretation was performed in accordance with the ACMG guidelines. By this, a molecular diagnosis was established in 34% of cases and candidate mutations were identified in additional 24% of patients. Detection rates of causative mutations were above 30%, regardless of further symptoms, except for patients with seizures (23%). We did not detect an advantage from partial exome sequencing for patients with severe intellectual disability (36%) as compared to those with mild intellectual disability (44%). Specific clinical diagnoses pre-existed for 20 patients. Of these, 5 could be confirmed and an additional 6 cases could be solved, but showed mutations in other genes than initially suspected. In conclusion partial exome sequencing solved >30% of intellectual disability cases, which is similar to published rates obtained by whole exome sequencing. The approach therefore proved to be a valid alternative to whole exome sequencing for molecular diagnostics in this cohort. The method proved equally suitable for both syndromic and non-syndromic intellectual disability forms of all severity grades.
Assuntos
Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/genética , Sequenciamento do Exoma/métodos , Exoma/genética , Anormalidades Múltiplas/genética , Criança , Estudos de Coortes , Análise Mutacional de DNA , Feminino , Genes Recessivos , Variação Genética , Humanos , Deficiência Intelectual/genética , Masculino , Mutação , Malformações do Sistema Nervoso/genética , Fenótipo , Gravidez , Análise de Sequência de DNA , SíndromeRESUMO
BACKGROUND: Breast cancer is the most prevalent tumor entity in Li-Fraumeni syndrome. Up to 80% of individuals with a Li-Fraumeni-like phenotype do not harbor detectable causative germline TP53 variants. Yet, no systematic panel analyses for a wide range of cancer predisposition genes have been conducted on cohorts of women with breast cancer fulfilling Li-Fraumeni(-like) clinical diagnostic criteria. METHODS: To specifically help explain the diagnostic gap of TP53 wild-type Li-Fraumeni(-like) breast cancer cases, we performed array-based CGH (comparative genomic hybridization) and panel-based sequencing of 94 cancer predisposition genes on 83 breast cancer patients suggestive of Li-Fraumeni syndrome who had previously had negative test results for causative BRCA1, BRCA2, and TP53 germline variants. RESULTS: We identified 13 pathogenic or likely pathogenic germline variants in ten patients and in nine genes, including four copy number aberrations and nine single-nucleotide variants or small indels. Three patients presented as double-mutation carriers involving two different genes each. In five patients (5 of 83; 6% of cohort), we detected causative pathogenic variants in established hereditary breast cancer susceptibility genes (i.e., PALB2, CHEK2, ATM). Five further patients (5 of 83; 6% of cohort) were found to harbor pathogenic variants in genes lacking a firm association with breast cancer susceptibility to date (i.e., Fanconi pathway genes, RECQ family genes, CDKN2A/p14ARF, and RUNX1). CONCLUSIONS: Our study details the mutational spectrum in breast cancer patients suggestive of Li-Fraumeni syndrome and indicates the need for intensified research on monoallelic variants in Fanconi pathway and RECQ family genes. Notably, this study further reveals a large portion of still unexplained Li-Fraumeni(-like) cases, warranting comprehensive investigation of recently described candidate genes as well as noncoding regions of the TP53 gene in patients with Li-Fraumeni(-like) syndrome lacking TP53 variants in coding regions.
Assuntos
Neoplasias da Mama/genética , Predisposição Genética para Doença , Mutação em Linhagem Germinativa/genética , Síndrome de Li-Fraumeni/genética , Adulto , Estudos de Coortes , Variações do Número de Cópias de DNA , Análise Mutacional de DNA/métodos , Feminino , Testes Genéticos/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único , Proteína Supressora de Tumor p53/genética , Adulto JovemRESUMO
Posterior amorphous corneal dystrophy (PACD) (OMIM 612868) is a rare autosomal dominant disorder characterized by partial or complete posterior lamellar corneal opacification, decreased corneal thickness and flattening of the corneal curvature. PACD is associated with heterozygous deletions in chromosome band 12q21.33 harboring DCN, KERA, LUM, and EPYC which encode small leucine-rich proteoglycans. We report on a 7-year-old male patient with PACD who had an interstitial deletion of 1.3 Mb in 12q21.33. His mother carried a balanced insertional translocation involving this 12q21.33 segment which was inserted into the proximal part of the long arm of one chromosome 13. The patient corroborates previous observations that PACD is a contiguous gene syndrome caused by combined haploinsufficiency of DCN, KERA, LUM, and EPYC and provides the first example of a balanced chromosome rearrangement involving 12q21.33 in an unaffected parent.