Keller M.F.,U.S. National Institute on Aging |
Keller M.F.,Temple University |
Ferrucci L.,U.S. National Institute on Aging |
Singleton A.B.,U.S. National Institute on Aging |
And 6 more authors.
IMPORTANCE: Considerable advances have been made in our understanding of the genetics underlying amyotrophic lateral sclerosis (ALS). Nevertheless, for the majority of patients who receive a diagnosis of ALS, the role played by genetics is unclear. Further elucidation of the genetic architecture of this disease will help clarify the role of genetic variation in ALS populations. OBJECTIVE: To estimate the relative importance of genetic factors in a complex disease such as ALS by accurately quantifying heritability using genome-wide data derived from genome-wide association studies. DESIGN, SETTING, AND PARTICIPANTS: We applied the genome-wide complex trait analysis algorithm to 3 genome-wide association study data sets thatwere generated from ALS case-control cohorts of European ancestry to estimate the heritability of ALS. Cumulatively, these data sets contained genotype data from 1223 cases and 1591 controls that had been previously generated and are publically available on the National Center for Biotechnology Information database of genotypes and phenotypeswebsite (http://www.ncbi.nlm.nih.gov/gap). The cohorts genotyped as part of these genome-wide association study efforts include the InCHIANTI (aging in the Chianti area) Study, the Piemonte and Valle d'Aosta Register for Amyotrophic Lateral Sclerosis, the National Institute of Neurological Disorders and Stroke Repository, and an ALS specialty clinic in Helsinki, Finland. MAIN OUTCOMES AND MEASURES: A linear mixed model was used to account for all known single-nucleotide polymorphisms simultaneously and to quantify the phenotypic variance present in ostensibly outbred individuals. Variance measures were used to estimate heritability. RESULTS: With our meta-analysis, which is based on genome-wide genotyping data, we estimated the overall heritability of ALS to be approximately 21.0% (95% CI, 17.1-24.9) (SE = 2.0%), indicating that additional genetic variation influencing risk of ALS loci remains to be identified. Furthermore, we identified 17 regions of the genome that display significantly high heritability estimates. Eleven of these regions represent novel candidate regions for ALS risk. CONCLUSIONS AND RELEVANCE: We found the heritability of ALS to be significantly higher than previously reported. We also identified multiple, novel genomic regions that we hypothesizemay contain causative risk variants that influence susceptibility to ALS. Copyright 2014 American Medical Association. All rights reserved. Source
Chio A.,University of Turin |
Battistini S.,University of Siena |
Calvo A.,University of Turin |
Caponnetto C.,University of Genoa |
And 13 more authors.
Journal of Neurology, Neurosurgery and Psychiatry
The clinical approach to patients with amyotrophic lateral sclerosis (ALS) has been largely modified by the identification of novel genes, the detection of gene mutations in apparently sporadic patients, and the discovery of the strict genetic and clinical relation between ALS and frontotemporal dementia (FTD). As a consequence, clinicians are increasingly facing the dilemma on how to handle genetic counselling and testing both for ALS patients and their relatives. On the basis of existing literature on genetics of ALS and of other late-onset life-threatening disorders, we propose clinical suggestions to enable neurologists to provide optimal clinical and genetic counselling to patients and families. Genetic testing should be offered to ALS patients who have a first-degree or second-degree relative with ALS, FTD or both, and should be discussed with, but not offered to, all other ALS patients, with special emphasis on its major uncertainties. Presently, genetic testing should not be proposed to asymptomatic at-risk subjects, unless they request it or are enrolled in research programmes. Genetic counselling in ALS should take into account the uncertainties about the pathogenicity and penetrance of some genetic mutations; the possible presence of mutations of different genes in the same individual; the poor genotypic/phenotypic correlation in most ALS genes; and the phenotypic pleiotropy of some genes. Though psychological, social and ethical implications of genetic testing are still relatively unexplored in ALS, we recommend multidisciplinary counselling that addresses all relevant issues, including disclosure of tests results to family members and the risk for genetic discrimination. Source
Nogueira L.,Molecular Genetics Unit |
Ruiz-Ontanon P.,Molecular Genetics Unit |
Vazquez-Barquero A.,Service of Neurosurgery |
Moris F.,Entrechem |
Fernandez-Luna J.L.,Molecular Genetics Unit
Cancer initiating cells have been described to be the only cell population with tumorigenic capacity in glioblastoma multiforme, one of the most aggressive and untreatable cancers. Recent work from our group described that NFκB pathway was activated in glioblastoma initiating cells undergoing differentiation, and that blockade of this activation promoted senescence of differentiating cells. NFκB activation in cancer may be the result of either exposure to proinflammatory stimuli in the tumor microenvironment or upregulation of the signaling pathway by upstream regulators. Appropriate control of NFκB activity, which can be achieved by gene modification or pharmacological strategies, would provide a potential approach for the management of NFκB related tumors, including glioblastoma. Here, we summarize the current knowledge of the relevance of NFκB in cancer and its possible role as a target of therapeutic intervention. © Nogueira et al. Source
Hernan I.,Molecular Genetics Unit |
Borrs E.,Molecular Genetics Unit |
De Sousa Dias M.,Molecular Genetics Unit |
Gamundi M.J.,Molecular Genetics Unit |
And 5 more authors.
Journal of Molecular Diagnostics
Advances in sequencing technologies, such as next-generation sequencing (NGS), represent an opportunity to perform genetic testing in a clinical scenario. In this study, we developed and tested a method for the detection of mutations in the large BRCA1 and BRCA2 tumor suppressor genes, using long-range PCR (LR-PCR) and NGS, in samples from individuals with a personal and/or family history of breast and/or ovarian cancer. Eleven LR-PCR fragments, between 3000 and 15,300 bp, containing all coding exons and flanking splice junctions of BRCA1 and BRCA2, were obtained from DNA samples of five individuals carrying mutations in either BRCA1 or BRCA2. Libraries for NGS were prepared using an enzymatic (Nextera technology) method. We analyzed five individual samples in parallel by NGS and obtained complete coverage of all LR-PCR fragments, with an average coding sequence depth for each nucleotide of >30 reads, running from ×7 (in exon 22 of BRCA1) to >×150. We detected and confirmed 100% of the mutations that predispose to the risk of cancer, together with other genomic variations in BRCA1 and BRCA2. Our approach demonstrates that genomic LR-PCR, together with NGS, using the GS Junior 454 System platform, is an effective method for patient sample analysis of BRCA1 and BRCA2 genes. In addition, this method could be performed in regular molecular genetics laboratories. © 2012 American Society for Investigative Pathology and the Association for Molecular Pathology. Source
Borras E.,Molecular Genetics Unit |
Jurado I.,Pathology Service |
Hernan I.,Molecular Genetics Unit |
Gamundi M.J.,Molecular Genetics Unit |
And 7 more authors.
Background: Epidermal growth factor receptor (EGFR) and its downstream factors KRAS and BRAF are mutated in several types of cancer, affecting the clinical response to EGFR inhibitors. Mutations in the EGFR kinase domain predict sensitivity to the tyrosine kinase inhibitors gefitinib and erlotinib in lung adenocarcinoma, while activating point mutations in KRAS and BRAF confer resistance to the anti-EGFR monoclonal antibody cetuximab in colorectal cancer. The development of new generation methods for systematic mutation screening of these genes will allow more appropriate therapeutic choices.Methods: We describe a high resolution melting (HRM) assay for mutation detection in EGFR exons 19-21, KRAS codon 12/13 and BRAF V600 using formalin-fixed paraffin-embedded samples. Somatic variation of KRAS exon 2 was also analysed by massively parallel pyrosequencing of amplicons with the GS Junior 454 platform.Results: We tested 120 routine diagnostic specimens from patients with colorectal or lung cancer. Mutations in KRAS, BRAF and EGFR were observed in 41.9%, 13.0% and 11.1% of the overall samples, respectively, being mutually exclusive. For KRAS, six types of substitutions were detected (17 G12D, 9 G13D, 7 G12C, 2 G12A, 2 G12V, 2 G12S), while V600E accounted for all the BRAF activating mutations. Regarding EGFR, two cases showed exon 19 deletions (delE746-A750 and delE746-T751insA) and another two substitutions in exon 21 (one showed L858R with the resistance mutation T590M in exon 20, and the other had P848L mutation). Consistent with earlier reports, our results show that KRAS and BRAF mutation frequencies in colorectal cancer were 44.3% and 13.0%, respectively, while EGFR mutations were detected in 11.1% of the lung cancer specimens. Ultra-deep amplicon pyrosequencing successfully validated the HRM results and allowed detection and quantitation of KRAS somatic mutations.Conclusions: HRM is a rapid and sensitive method for moderate-throughput cost-effective screening of oncogene mutations in clinical samples. Rather than Sanger sequence validation, next-generation sequencing technology results in more accurate quantitative results in somatic variation and can be achieved at a higher throughput scale. © 2011 Borràs et al; licensee BioMed Central Ltd. Source