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Li B, Liu J, Huang Q. A Digital PCR Method Based on Highly Specific Taq for Detecting Gene Editing and Mutations. Int J Mol Sci 2023; 24:13405. [PMID: 37686219 PMCID: PMC10488114 DOI: 10.3390/ijms241713405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 08/25/2023] [Accepted: 08/27/2023] [Indexed: 09/10/2023] Open
Abstract
Digital PCR (dPCR) has great potential for assessing gene editing or gene mutation due to its ability to independently inspect each DNA template in parallel. However, current dPCR methods use a fluorescence-labeled probe to detect gene variation events, and their ability to distinguish variated sequences from the wild-type sequence is limited by the probe's tolerance to mismatch. To address this, we have developed a novel dPCR method that uses a primer instead of a probe to sense gene variation. The enhanced Taq DNA polymerase in the PCR system has a high mismatch sensitivity, which enables our dPCR method to distinguish gene mutations from wild-type sequences. Compared to current dPCR methods, our method shows superior precision in assessing gene editing efficiency and single-base DNA mutation. This presents a promising opportunity to advance gene editing research and rare gene mutation detection.
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Affiliation(s)
| | | | - Qilai Huang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao 266237, China
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2
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Augustine SM, Cherian AV, Seiling K, Di Fiore S, Raven N, Commandeur U, Schillberg S. Targeted mutagenesis in Nicotiana tabacum ADF gene using shockwave-mediated ribonucleoprotein delivery increases osmotic stress tolerance. PHYSIOLOGIA PLANTARUM 2021; 173:993-1007. [PMID: 34265107 DOI: 10.1111/ppl.13499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
DNA-free genome editing involves the direct introduction of ribonucleoprotein (RNP) complexes into cells, but this strategy has rarely been successful in plants. In the present study, we describe a new technique for the introduction of RNPs into plant cells involving the generation of cavitation bubbles using a pulsed laser. The resulting shockwave achieves the efficient transfection of walled cells in tissue explants by creating transient membrane pores. RNP-containing cells were rapidly identified by fluorescence microscopy, followed by regeneration and the screening of mutant plants by high-resolution melt analysis. We used this technique in Nicotiana tabacum to target the endogenous phytoene desaturase (PDS) and actin depolymerizing factor (ADF) genes. Genome-edited plants were produced with an efficiency of 35.2% for PDS and 16.5% for ADF. Further we evaluated the physiological, cellular and molecular effects of ADF mutations in T2 mutant plants under drought and salinity stress. The results suggest that ADF acts as a key regulator of osmotic stress tolerance in plants.
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Affiliation(s)
- Sruthy Maria Augustine
- Institute of Molecular Biotechnology, RWTH Aachen University, Worringer Weg 1, Aachen, Germany
- Department of Plant breeding, IFZ Research Center for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26, Giessen, Germany
| | - Anoop Vadakan Cherian
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, Aachen, Germany
- Center for Infection and Genomics of the Lung (CIGL), Justus-Liebig-Universität Gießen - Institut für Klinische Immunologie und Transfusionsmedizin, Aulweg 132, Giessen, Germany
| | - Kerstin Seiling
- Institute of Molecular Biotechnology, RWTH Aachen University, Worringer Weg 1, Aachen, Germany
- Institute for Anatomy and Molecular neurobiology, Universitätsklinikum Münster, Vesaliusweg 2-4, Münster, Germany
| | - Stefano Di Fiore
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, Aachen, Germany
| | - Nicole Raven
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, Aachen, Germany
| | - Ulrich Commandeur
- Institute of Molecular Biotechnology, RWTH Aachen University, Worringer Weg 1, Aachen, Germany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, Aachen, Germany
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3
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Loutfy SA, Abdallah ZF, Shaalan M, Moneer M, Karam A, Moneer MM, Sayed IM, Abd El-Hafeez AA, Ghosh P, Zekri ARN. Prevalence of MMTV-Like env Sequences and Its Association with BRCA1/2 Genes Mutations Among Egyptian Breast Cancer Patients. Cancer Manag Res 2021; 13:2835-2848. [PMID: 33814932 PMCID: PMC8009344 DOI: 10.2147/cmar.s294584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 03/01/2021] [Indexed: 01/04/2023] Open
Abstract
Background Mouse mammary tumor virus (MMTV) is thought to have a role in human breast cancer (BC) pathogenesis. BRCA1 and 2 genes mutations are well-established risk factors for BC. The purpose of this study was to evaluate the presence of MMTV in familial and non-familial Egyptian breast cancer patients. We also aimed to establish a correlation between BRCAs genes mutations and MMTV infection in those patients. Patients and Methods The study was included 80 BC patients and 10 healthy women were included as a control group. We used PCR to amplify a 250-bp MMTV-like env sequence. We also used PCR followed by direct sequencing to identify the genetic variation of exons 2, 13, 19 of BRCA1 gene and exon 9 and region f of exon 11 of BRCA2 gene. High resolution melting (HRM) analysis was used to screen the selected exons of BRCA1/2 genes in order to detect different variants. Results MMTV DNA-like env sequences were detected in 70%, 76% of familial and non-familial BC patients, respectively, and it was not detected in any of the control subjects. The presence of viral sequences was associated with larger tumor size in the sporadic patients. Seventy BC patients showed variations in BRCA1/2 genes according to HRM analysis and sequencing analysis showed two different sequences of polymorphism among 22 familial and non-familial BC patients. Conclusion MMTV DNA was present among BC patients and it was associated with increased tumor growth. This indicates a potential role for MMTV in BC patients with and without deleterious mutation in BRCA1/2 genes.
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Affiliation(s)
- Samah A Loutfy
- Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Zeinab F Abdallah
- Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Mohamed Shaalan
- Surgical Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Mohamed Moneer
- Surgical Oncology Department, Materia Teaching Hospital, Cairo, Egypt
| | - Adel Karam
- Surgical Oncology Department, Materia Teaching Hospital, Cairo, Egypt
| | - Manar M Moneer
- Biostatistics and Epidemiology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Ibrahim M Sayed
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt.,Department of Pathology, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Amer Ali Abd El-Hafeez
- Pharmacology and Experimental Oncology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.,Department of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Abdel-Rahman N Zekri
- Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
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Holt RJ, Young RM, Crespo B, Ceroni F, Curry CJ, Bellacchio E, Bax DA, Ciolfi A, Simon M, Fagerberg CR, van Binsbergen E, De Luca A, Memo L, Dobyns WB, Mohammed AA, Clokie SJ, Zazo Seco C, Jiang YH, Sørensen KP, Andersen H, Sullivan J, Powis Z, Chassevent A, Smith-Hicks C, Petrovski S, Antoniadi T, Shashi V, Gelb BD, Wilson SW, Gerrelli D, Tartaglia M, Chassaing N, Calvas P, Ragge NK. De Novo Missense Variants in FBXW11 Cause Diverse Developmental Phenotypes Including Brain, Eye, and Digit Anomalies. Am J Hum Genet 2019; 105:640-657. [PMID: 31402090 PMCID: PMC6731360 DOI: 10.1016/j.ajhg.2019.07.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/09/2019] [Indexed: 12/20/2022] Open
Abstract
The identification of genetic variants implicated in human developmental disorders has been revolutionized by second-generation sequencing combined with international pooling of cases. Here, we describe seven individuals who have diverse yet overlapping developmental anomalies, and who all have de novo missense FBXW11 variants identified by whole exome or whole genome sequencing and not reported in the gnomAD database. Their phenotypes include striking neurodevelopmental, digital, jaw, and eye anomalies, and in one individual, features resembling Noonan syndrome, a condition caused by dysregulated RAS signaling. FBXW11 encodes an F-box protein, part of the Skp1-cullin-F-box (SCF) ubiquitin ligase complex, involved in ubiquitination and proteasomal degradation and thus fundamental to many protein regulatory processes. FBXW11 targets include β-catenin and GLI transcription factors, key mediators of Wnt and Hh signaling, respectively, critical to digital, neurological, and eye development. Structural analyses indicate affected residues cluster at the surface of the loops of the substrate-binding domain of FBXW11, and the variants are predicted to destabilize the protein and/or its interactions. In situ hybridization studies on human and zebrafish embryonic tissues demonstrate FBXW11 is expressed in the developing eye, brain, mandibular processes, and limb buds or pectoral fins. Knockdown of the zebrafish FBXW11 orthologs fbxw11a and fbxw11b resulted in embryos with smaller, misshapen, and underdeveloped eyes and abnormal jaw and pectoral fin development. Our findings support the role of FBXW11 in multiple developmental processes, including those involving the brain, eye, digits, and jaw.
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Holt R, Ceroni F, Bax DA, Broadgate S, Diaz DG, Santos C, Gerrelli D, Ragge NK. New variant and expression studies provide further insight into the genotype-phenotype correlation in YAP1-related developmental eye disorders. Sci Rep 2017; 7:7975. [PMID: 28801591 PMCID: PMC5554234 DOI: 10.1038/s41598-017-08397-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/07/2017] [Indexed: 01/06/2023] Open
Abstract
YAP1, which encodes the Yes-associated protein 1, is part of the Hippo pathway involved in development, growth, repair and homeostasis. Nonsense YAP1 mutations have been shown to co-segregate with autosomal dominantly inherited coloboma. Therefore, we screened YAP1 for variants in a cohort of 258 undiagnosed UK patients with developmental eye disorders, including anophthalmia, microphthalmia and coloboma. We identified a novel 1 bp deletion in YAP1 in a boy with bilateral microphthalmia and bilateral chorioretinal coloboma. This variant is located in the coding region of all nine YAP1 spliceforms, and results in a frameshift and subsequent premature termination codon in each. The variant is predicted to result in the loss of part of the transactivation domain of YAP1, and sequencing of cDNA from the patient shows it does not result in nonsense mediated decay. To investigate the role of YAP1 in human eye development, we performed in situ hybridisation utilising human embryonic tissue, and observed expression in the developing eye, neural tube, brain and kidney. These findings help confirm the role of YAP1 and the Hippo developmental pathway in human eye development and its associated anomalies and demonstrate its expression during development in affected organ systems.
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Affiliation(s)
- R Holt
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - F Ceroni
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - D A Bax
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - S Broadgate
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - D Gold Diaz
- Institute of Child Health, University College London, London, UK
| | - C Santos
- Institute of Child Health, University College London, London, UK
| | - D Gerrelli
- Institute of Child Health, University College London, London, UK
| | - N K Ragge
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK. .,Clinical Genetics Unit, West Midlands Regional Genetics Service, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK.
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Comparison of traditional and new generation DNA markers declares high genetic diversity and differentiated population structure of wild almond species. Sci Rep 2017; 7:5966. [PMID: 28729554 PMCID: PMC5519738 DOI: 10.1038/s41598-017-06084-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/16/2017] [Indexed: 01/07/2023] Open
Abstract
Wild almond species as sources of genetic variation may have crucial importance in breeding. A total of 389 accessions of 18 species have been analysed using inter-retrotransposon amplified polymorphism (IRAP), retrotransposon-microsatellite amplified polymorphism (REMAP), sequence-specific amplification polymorphism (S-SAP), amplified fragment length polymorphism (AFLP), inter simple sequence repeat (ISSR) and simple sequence repeats (SSR). Retrotransposon markers indicated the presence and movement of some Ty3-gypsy and Ty1-copia-elements in almond genome. Since transposable elements are associated with large-scale genome alterations, REMAP produced more reliable phylogenetic inferences than AFLP where homoplasy may affect clustering. In addition, high resolution melting (HRM) analysis was developed to detect SNPs. HRM analysis revealed 1:189 bp frequency of SNPs in exon positions, and the transition-to-transversion proportion was 1.84:1. The low transition bias suggests low methylation levels in almond genome. The polymorphic information content (PIC) was the highest for SSR markers, while SNPs had an average PIC of 0.59, which is close to the values of the rest of the markers. Huge genetic diversity, fragmented population structure and footprints of human selection was confirmed by merging information from all marker strategies. Considering time, cost and performance HRM can be a marker of choice in future studies of Prunus diversity.
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Milley GM, Varga ET, Grosz Z, Bereznai B, Aranyi Z, Boczan J, Dioszeghy P, Kálmán B, Gal A, Molnar MJ. Three novel mutations and genetic epidemiology analysis of the Gap Junction Beta 1 (GJB1) gene among Hungarian Charcot-Marie-Tooth disease patients. Neuromuscul Disord 2016; 26:706-711. [PMID: 27544631 DOI: 10.1016/j.nmd.2016.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/14/2016] [Accepted: 07/25/2016] [Indexed: 02/03/2023]
Abstract
Pathogenic variants of the gap junction beta 1 (GJB1) gene are responsible for the Charcot-Marie-Tooth neuropathy X type 1 (CMTX1). In this study, we report the mutation frequency of GJB1 in 210 Hungarian CMT patients and the phenotype comparison between male and female CMTX1 patients. Altogether, 13 missense substitutions were found in the GJB1 gene. Among them, 10 have been previously described as pathogenic variants (p.Arg15Trp, p.Val63Ile, p.Leu89Val, p.Ala96Gly, p.Arg107Trp, p.Arg142Gln, p.Arg164Trp, p.Arg164Gln, p.Pro172Ala and p.Asn205Ser), while 3 were novel, likely pathogenic alterations (p.Val13Glu, p.Glu186Gly, p.Met194Ile). These variants were not present in controls and were predicted as disease causing by in silico analysis. The frequency of the variants was 6.7% in our cohort which refers to a common cause of hereditary neuropathy among Hungarian patients. In addition to the classical phenotype, CNS involvement was proved in 26.1% of the CMTX1 patients. GJB1 pathogenic alterations were found mainly in males but we also detected them in female probands. The statistical analysis of CMTX1 patients revealed a significant difference between the two genders regarding the age of onset, Charcot-Marie-Tooth neuropathy and examination scores.
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Affiliation(s)
- Gyorgy Mate Milley
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary
| | - Edina Timea Varga
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary; Department of Neurology, University of Szeged, Szeged, Hungary
| | - Zoltan Grosz
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary
| | - Benjamin Bereznai
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary
| | - Zsuzsanna Aranyi
- MTA-SE NAP B Peripheral Nervous System Research Group, Dept. of Neurology, Semmelweis University, Budapest, Hungary
| | - Judit Boczan
- Department of Neurology, Medical Center, University of Debrecen, Debrecen, Hungary
| | - Peter Dioszeghy
- Department of Neurology, Andras Josa Teaching Hospital, Nyiregyhaza, Hungary
| | - Bernadette Kálmán
- University of Pecs, Faculty of Health Sciences, Pecs and Molecular Pathology, Markusovszky University Teaching Hospital, Szombathely, Hungary
| | - Aniko Gal
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary
| | - Maria Judit Molnar
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary.
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Song C, Castellanos-Rizaldos E, Bejar R, Ebert BL, Makrigiorgos GM. DMSO Increases Mutation Scanning Detection Sensitivity of High-Resolution Melting in Clinical Samples. Clin Chem 2015; 61:1354-62. [PMID: 26432802 DOI: 10.1373/clinchem.2015.245357] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/17/2015] [Indexed: 02/02/2023]
Abstract
BACKGROUND Mutation scanning provides the simplest, lowest-cost method for identifying DNA variations on single PCR amplicons, and it may be performed before sequencing to avoid screening of noninformative wild-type samples. High-resolution melting (HRM) is the most commonly used method for mutation scanning. With PCR-HRM, however, mutations less abundant than approximately 3%-10% that can still be clinically significant may often be missed. Therefore, enhancing HRM detection sensitivity is important for mutation scanning and its clinical application. METHODS We used serial dilution of cell lines containing the TP53 exon 8 mutation to demonstrate the improvement in detection sensitivity for conventional-PCR-HRM in the presence of DMSO. We also conducted coamplification at lower denaturation temperature (COLD)-PCR with an extra step for cross-hybridization, followed by preferential denaturation and amplification at optimized critical temperature (full-COLD-PCR), to further enrich low-level mutations before HRM with or without DMSO, and we used droplet-digital PCR to derive the optimal conditions for mutation enrichment. Both conventional PCR-HRM and full-COLD-PCR-HRM with and without DMSO were used for mutation scanning of TP53 exon 8 in cancer samples containing known mutations and myelodysplastic syndrome samples with unknown mutations. Mutations in other genes were also examined. RESULTS The detection sensitivity of PCR-HRM scanning increases 2- to 5-fold in the presence of DMSO, depending on mutation type and sequence context, and can typically detect mutation abundance of approximately 1%. When mutation enrichment is applied during amplification with full-COLD-PCR followed by HRM in the presence of DMSO, mutations with 0.2%-0.3% abundance in TP53 exon 8 can be detected. CONCLUSIONS DMSO improves HRM mutation scanning sensitivity with saturating dyes. When full-COLD-PCR is used, followed by DMSO-HRM, the overall improvement is about 20-fold compared with conventional PCR-HRM.
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Affiliation(s)
- Chen Song
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Elena Castellanos-Rizaldos
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Rafael Bejar
- Division of Hematology and Oncology, UCSD Moores Cancer Center, La Jolla, CA
| | - Benjamin L Ebert
- Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - G Mike Makrigiorgos
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital, Harvard Medical School, Boston, MA;
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Drew AP, Zhu D, Kidambi A, Ly C, Tey S, Brewer MH, Ahmad-Annuar A, Nicholson GA, Kennerson ML. Improved inherited peripheral neuropathy genetic diagnosis by whole-exome sequencing. Mol Genet Genomic Med 2015; 3:143-54. [PMID: 25802885 PMCID: PMC4367087 DOI: 10.1002/mgg3.126] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/07/2014] [Accepted: 11/13/2014] [Indexed: 12/31/2022] Open
Abstract
Inherited peripheral neuropathies (IPNs) are a group of related diseases primarily affecting the peripheral motor and sensory neurons. They include the hereditary sensory neuropathies (HSN), hereditary motor neuropathies (HMN), and Charcot-Marie-Tooth disease (CMT). Using whole-exome sequencing (WES) to achieve a genetic diagnosis is particularly suited to IPNs, where over 80 genes are involved with weak genotype–phenotype correlations beyond the most common genes. We performed WES for 110 index patients with IPN where the genetic cause was undetermined after previous screening for mutations in common genes selected by phenotype and mode of inheritance. We identified 41 missense sequence variants in the known IPN genes in our cohort of 110 index patients. Nine variants (8%), identified in the genes MFN2, GJB1, BSCL2, and SETX, are previously reported mutations and considered to be pathogenic in these families. Twelve novel variants (11%) in the genes NEFL, TRPV4, KIF1B, BICD2, and SETX are implicated in the disease but require further evidence of pathogenicity. The remaining 20 variants were confirmed as polymorphisms (not causing the disease) and are detailed here to help interpret sequence variants identified in other family studies. Validation using segregation, normal controls, and bioinformatics tools was valuable as supporting evidence for sequence variants implicated in disease. In addition, we identified one SETX sequence variant (c.7640T>C), previously reported as a putative mutation, which we have confirmed as a nonpathogenic rare polymorphism. This study highlights the advantage of using WES for genetic diagnosis in highly heterogeneous diseases such as IPNs and has been particularly powerful in this cohort where genetic diagnosis could not be achieved due to phenotype and mode of inheritance not being previously obvious. However, first tier testing for common genes in clinically well-defined cases remains important and will account for most positive results.
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Affiliation(s)
- Alexander P Drew
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia
| | - Danqing Zhu
- Molecular Medicine Laboratory, Concord Hospital Sydney, Australia
| | - Aditi Kidambi
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia
| | - Carolyn Ly
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia
| | - Shelisa Tey
- Department of Biomedical Science, Faculty of Medicine, University of Malaya 50603, Kuala Lumpur, Malaysia
| | - Megan H Brewer
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia ; Sydney Medical School, University of Sydney Sydney, Australia
| | - Azlina Ahmad-Annuar
- Department of Biomedical Science, Faculty of Medicine, University of Malaya 50603, Kuala Lumpur, Malaysia
| | - Garth A Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia ; Molecular Medicine Laboratory, Concord Hospital Sydney, Australia ; Sydney Medical School, University of Sydney Sydney, Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia ; Molecular Medicine Laboratory, Concord Hospital Sydney, Australia ; Sydney Medical School, University of Sydney Sydney, Australia
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Mondini L, Nachit MM, Pagnotta MA. Allelic variants in durum wheat (Triticum turgidum L. var. durum) DREB genes conferring tolerance to abiotic stresses. Mol Genet Genomics 2014; 290:531-44. [PMID: 25332074 DOI: 10.1007/s00438-014-0933-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 10/03/2014] [Indexed: 11/25/2022]
Abstract
To identify potential and useful markers able to discriminate promising lines of durum wheat (Triticum turgidum L. var durum) tolerant to salt and drought stresses, nucleotide sequences of Dehydration-Responsive-Element Binding Factor (DREB) genes were used to design primers probed with High Resolution Melting technology for the identification of allelic variants. DREB1, DREB2, DREB3, DREB4 and DREB5 conserved regions corresponding to EREBP/AP2 domain and containing the conserved core sequence (5'-TACCGACAT-3'), the protein site directly involved in DNA recognition, were analyzed. The validated primers were probed on four lines of durum wheat differentially tolerant to salt and drought stresses treated with solutions containing different salt concentrations. Some SNPs mutations were identified in the highly tolerant durum cultivar Jennah Khetifa treated with the maximum salt concentration (1.5 M). The SNPs mutations identified were non-synonymous (nsSNPs) causing changes in peptide sequences. These concerned amino acid residues directly involved in the maintenance of protein geometry, the recognition of the specific cis-element, and the contacts between the protein and DNA. A validation of the found SNPs was carried out by analyzing the regressions between DREBs SNPs allelic variants and some morpho-physiological characters in a RIL population, deriving from a cross between the two durum wheat genotypes utilized for SNPs detection, grown under contrasting environments. Several phenotypical characters have been assessed in the progeny across all the localities evaluating the different performances under different stress levels and related with SNPs occurrence. Significant relations between SNPs variants and morpho-physiological characteristics were found in the progeny growth in very severe drought environments, suggesting a role of the identified SNPs in conferring a superior capability to adverse stress conditions and, at the same time, the key role of these genes in empowering salt tolerance.
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Affiliation(s)
- Linda Mondini
- Department of Science and Technologies for Agriculture, Forestry, Nature and Energy (DAFNE), Tuscia University, via S. C. de Lellis, 01100, Viterbo, Italy
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11
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Handt M, Epplen A, Hoffjan S, Mese K, Epplen JT, Dekomien G. Point mutation frequency in the FMR1 gene as revealed by fragile X syndrome screening. Mol Cell Probes 2014; 28:279-83. [PMID: 25171808 DOI: 10.1016/j.mcp.2014.08.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 08/18/2014] [Accepted: 08/18/2014] [Indexed: 01/05/2023]
Abstract
Fragile X syndrome (FXS) is a common cause of intellectual disability, developmental delay and autism spectrum disorders. This syndrome is due to a functional loss of the FMR1 gene product FMRP, and, in most cases, it is caused by CGG repeat expansion in the FMR1 promoter. Yet, also other FMR1 mutations may cause a FXS-like phenotype. Since standard molecular testing does not include the analysis of the FMR1 coding region, the prevalence of point mutations causing FXS is not well known. Here, high resolution melting (HRM) was used to screen for FMR1 gene mutations in 508 males with clinical signs of mental retardation and developmental delay, but without CGG and GCC repeat expansions in the FMR1 gene and AFF2 genes, respectively. Sequence variations were identified by HRM analysis and verified by direct DNA sequencing. Two novel missense mutations (p.Gly482Ser in one patient and p.Arg534His in two unrelated patients), one intronic and two 3'-untranslated region (UTR) variations were identified in the FMR1 gene. Missense mutations in the FMR1 gene might account for a considerable proportion of cases in male patients with FXS-related symptoms, such as those linked to mental retardation and developmental delay.
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Affiliation(s)
- Maximilian Handt
- Faculty of Health, Witten/Herdecke University, Alfred-Herrhausen-Straße 50, 58448 Witten, Germany
| | - Andrea Epplen
- Human Genetics, Ruhr-University, Universitätsstraße 150, 44801 Bochum, Germany
| | - Sabine Hoffjan
- Human Genetics, Ruhr-University, Universitätsstraße 150, 44801 Bochum, Germany
| | - Kemal Mese
- Faculty of Health, Witten/Herdecke University, Alfred-Herrhausen-Straße 50, 58448 Witten, Germany
| | - Jörg T Epplen
- Faculty of Health, Witten/Herdecke University, Alfred-Herrhausen-Straße 50, 58448 Witten, Germany; Human Genetics, Ruhr-University, Universitätsstraße 150, 44801 Bochum, Germany
| | - Gabriele Dekomien
- Human Genetics, Ruhr-University, Universitätsstraße 150, 44801 Bochum, Germany.
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Carrillo J, Martínez P, Solera J, Moratilla C, González A, Manguán-García C, Aymerich M, Canal L, del Campo M, Dapena J, Escoda L, García-Sagredo J, Martín-Sala S, Rives S, Sevilla J, Sastre L, Perona R. High resolution melting analysis for the identification of novel mutations in DKC1 and TERT genes in patients with dyskeratosis congenita. Blood Cells Mol Dis 2012; 49:140-6. [DOI: 10.1016/j.bcmd.2012.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 04/23/2012] [Indexed: 12/27/2022]
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13
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Anasagasti A, Irigoyen C, Barandika O, López de Munain A, Ruiz-Ederra J. Current mutation discovery approaches in Retinitis Pigmentosa. Vision Res 2012; 75:117-29. [PMID: 23022136 DOI: 10.1016/j.visres.2012.09.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/08/2012] [Accepted: 09/13/2012] [Indexed: 12/22/2022]
Abstract
With a worldwide prevalence of about 1 in 3500-5000 individuals, Retinitis Pigmentosa (RP) is the most common form of hereditary retinal degeneration. It is an extremely heterogeneous group of genetically determined retinal diseases leading to progressive loss of vision due to impairment of rod and cone photoreceptors. RP can be inherited as an autosomal-recessive, autosomal-dominant, or X-linked trait. Non-Mendelian inheritance patterns such as digenic, maternal (mitochondrial) or compound heterozygosity have also been reported. To date, more than 65 genes have been implicated in syndromic and non-syndromic forms of RP, which account for only about 60% of all RP cases. Due to this high heterogeneity and diversity of inheritance patterns, the molecular diagnosis of syndromic and non-syndromic RP is very challenging, and the heritability of 40% of total RP cases worldwide remains unknown. However new sequencing methodologies, boosted by the human genome project, have contributed to exponential plummeting in sequencing costs, thereby making it feasible to include molecular testing for RP patients in routine clinical practice within the coming years. Here, we summarize the most widely used state-of-the-art technologies currently applied for the molecular diagnosis of RP, and address their strengths and weaknesses for the molecular diagnosis of such a complex genetic disease.
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Affiliation(s)
- Ander Anasagasti
- Division of Neurosciences, Instituto Biodonostia, San Sebastián, Gipuzkoa, Spain
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14
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Er TK, Chang JG. High-resolution melting: applications in genetic disorders. Clin Chim Acta 2012; 414:197-201. [PMID: 22995429 DOI: 10.1016/j.cca.2012.09.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 09/08/2012] [Accepted: 09/08/2012] [Indexed: 12/16/2022]
Abstract
High-resolution melting (HRM) analysis is a feasible and powerful method for mutation scanning of sequence variants. Denatured doubled-stranded DNA can be detected in fluorescence changes by increasing the melting temperature and wild-type and heterozygous samples can be easily differentiated in the melting plots. HRM analysis represents the next generation of mutation-scanning technology and offers considerable time and cost savings compared to other screening methods. HRM analysis is a closed-tube method, indicating that polymerase chain reaction amplification and subsequent analysis are sequentially performed in the well, making HRM analysis more convenient than other scanning methodologies. Taken together, HRM analysis can be used for high-throughput mutation screening for research, as well as for molecular diagnostic and clinical purposes. This review summarizes the effectiveness of HRM analysis in the diagnosis of autosomal recessive, dominant, and X-linked genetic disorders. Notably, we will also discuss the limitations of HRM analysis and how to overcome them.
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Affiliation(s)
- Tze-Kiong Er
- Division of Molecular Diagnostics, Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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15
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Mondini L, Nachit M, Porceddu E, Pagnotta MA. Identification of SNP mutations in DREB1, HKT1, and WRKY1 genes involved in drought and salt stress tolerance in durum wheat (Triticum turgidum L. var durum). OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2012; 16:178-87. [PMID: 22433076 DOI: 10.1089/omi.2011.0081] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Tolerance mechanisms to salinity and drought stress are quite complex. Plants have developed a complex and elaborate signaling network that ensures their adaptation to this stress. For example, salinity tolerance is thought to be due to three main factors: Na(+) exclusion, tolerance to Na(+) in the tissues and osmotic tolerance. Recently, many transcription factors for tolerance to salt and drought stresses have been identified. In this study, multialignments of conserved domains in DREB1, WRKY1 transcription factors (TFs), and HKT-1 have been utilized to design specific primers in order to identify functional single nucleotide polymorphisms (SNPs). These primers have been used to probe on several genotypes of durum wheat that are differentially tolerant to salt and drought stress; they were grown in increasing concentrations of NaCl. The selected portions have been analyzed using high-resolution melting curve (HRM) technology that currently represents one of the most recent and powerful tools for detecting SNP and INDEL mutations. Analyzing the amplification profiles, observed in the resulting melting curves, samples corresponding to different treatment conditions were selected, sequenced, and aligned with the homolog sequences present in gene databases to identify and characterize potential SNP and INDEL mutations. The PCR amplicons, containing single and double SNPs, produced distinctive HRM profiles. By sequencing the polymerase chain reaction (PCR) products, several SNPs have been identified and validated. All the discovered mutations were able to generate changes in amino acid sequences of the corresponding proteins. Most of the identified SNPs were found in salt and drought tolerant durum wheat genotypes. These varieties are of great value for durum wheat breeding works.
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Affiliation(s)
- Linda Mondini
- Department of Science and Technologies for Agriculture, Forestry, Nature and Energy, Tuscia University, Viterbo, Italy
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16
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Isolated NIBPL missense mutations that cause Cornelia de Lange syndrome alter MAU2 interaction. Eur J Hum Genet 2011; 20:271-6. [PMID: 21934712 DOI: 10.1038/ejhg.2011.175] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cornelia de Lange syndrome (CdLS; or Brachmann-de Lange syndrome) is a dominantly inherited congenital malformation disorder with features that include characteristic facies, cognitive delays, growth retardation and limb anomalies. Mutations in nearly 60% of CdLS patients have been identified in NIPBL, which encodes a regulator of the sister chromatid cohesion complex. NIPBL, also known as delangin, is a homolog of yeast and amphibian Scc2 and C. elegans PQN-85. Although the exact mechanism of NIPBL function in sister chromatid cohesion is unclear, in vivo yeast and C. elegans experiments and in vitro vertebrate cell experiments have demonstrated that NIPBL/Scc2 functionally interacts with the MAU2/Scc4 protein to initiate loading of cohesin onto chromatin. To test the significance of this model in the clinical setting of CdLS, we fine-mapped the NIBPL-MAU2 interaction domain and tested the functional significance of missense mutations and variants in NIPBL and MAU2 identified in these minimal domains in a cohort of patients with CdLS. We demonstrate that specific novel mutations at the N-terminus of the MAU2-interacting domain of NIBPL result in markedly reduced MAU2 binding, although we appreciate no consistent clinical difference in the small group of patients with these mutations. These data suggest that factors in addition to MAU2 are essential in determining the clinical features and severity of CdLS.
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17
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Tricarico R, Crucianelli F, Alvau A, Orlando C, Sestini R, Tonelli F, Valanzano R, Genuardi M. High resolution melting analysis for a rapid identification of heterozygous and homozygous sequence changes in the MUTYH gene. BMC Cancer 2011; 11:305. [PMID: 21777424 PMCID: PMC3156810 DOI: 10.1186/1471-2407-11-305] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 07/21/2011] [Indexed: 11/29/2022] Open
Abstract
Background MUTYH-associated polyposis (MAP) is an autosomal recessive form of intestinal polyposis predisposing to colorectal carcinoma. High resolution melting analysis (HRMA) is a mutation scanning method that allows detection of heterozygous sequence changes with high sensitivity, whereas homozygosity for a nucleotide change may not lead to significant curve shape or melting temperature changes compared to homozygous wild-type samples. Therefore, HRMA has been mainly applied to the detection of mutations associated with autosomal dominant or X-linked disorders, while applications to autosomal recessive conditions are less common. Methods MUTYH coding sequence and UTRs were analyzed by both HRMA and sequencing on 88 leukocyte genomic DNA samples. Twenty-six samples were also examined by SSCP. Experiments were performed both with and without mixing the test samples with wild-type DNA. Results The results show that all MUTYH sequence variations, including G > C and A > T homozygous changes, can be reliably identified by HRMA when a condition of artificial heterozygosity is created by mixing test and reference DNA. HRMA had a sensitivity comparable to sequencing and higher than SSCP. Conclusions The availability of a rapid and inexpensive method for the identification of MUTYH sequence variants is relevant for the diagnosis of colorectal cancer susceptibility, since the MAP phenotype is highly variable.
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Affiliation(s)
- Rossella Tricarico
- Department of Clinical Pathophysiology, Medical Genetics Unit, University of Florence, Florence, Italy
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18
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Hondow HL, Fox SB, Mitchell G, Scott RJ, Beshay V, Wong SQ, Dobrovic A. A high-throughput protocol for mutation scanning of the BRCA1 and BRCA2 genes. BMC Cancer 2011; 11:265. [PMID: 21702907 PMCID: PMC3146935 DOI: 10.1186/1471-2407-11-265] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 06/24/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Detection of mutations by DNA sequencing can be facilitated by scanning methods to identify amplicons which may have mutations. Current scanning methods used for the detection of germline sequence variants are laborious as they require post-PCR manipulation. High resolution melting (HRM) is a cost-effective rapid screening strategy, which readily detects heterozygous variants by melting curve analysis of PCR products. It is well suited to screening genes such as BRCA1 and BRCA2 as germline pathogenic mutations in these genes are always heterozygous. METHODS Assays for the analysis of all coding regions and intron-exon boundaries of BRCA1 and BRCA2 were designed, and optimised. A final set of 94 assays which ran under identical amplification conditions were chosen for BRCA1 (36) and BRCA2 (58). Significant attention was placed on primer design to enable reproducible detection of mutations within the amplicon while minimising unnecessary detection of polymorphisms. Deoxyinosine residues were incorporated into primers that overlay intronic polymorphisms. Multiple 384 well plates were used to facilitate high throughput. RESULTS 169 BRCA1 and 239 BRCA2 known sequence variants were used to test the amplicons. We also performed an extensive blinded validation of the protocol with 384 separate patient DNAs. All heterozygous variants were detected with the optimised assays. CONCLUSIONS This is the first HRM approach to screen the entire coding region of the BRCA1 and BRCA2 genes using one set of reaction conditions in a multi plate 384 well format using specifically designed primers. The parallel screening of a relatively large number of samples enables better detection of sequence variants. HRM has the advantages of decreasing the necessary sequencing by more than 90%. This markedly reduced cost of sequencing will result in BRCA1 and BRCA2 mutation testing becoming accessible to individuals who currently do not undergo mutation testing because of the significant costs involved.
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Affiliation(s)
- Heather L Hondow
- Molecular Pathology Research and Development Laboratory, Department of Pathology, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, Melbourne, Victoria, 8006, Australia
| | - Stephen B Fox
- Molecular Pathology Research and Development Laboratory, Department of Pathology, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, Melbourne, Victoria, 8006, Australia
- Department of Pathology, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Gillian Mitchell
- Familial Cancer Centre, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, Melbourne, Victoria, 8006, Australia
| | - Rodney J Scott
- School of Biomedical Sciences, University of Newcastle, New South Wales, 2308, Australia
| | - Victoria Beshay
- Molecular Pathology Research and Development Laboratory, Department of Pathology, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, Melbourne, Victoria, 8006, Australia
| | - Stephen Q Wong
- Molecular Pathology Research and Development Laboratory, Department of Pathology, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, Melbourne, Victoria, 8006, Australia
| | | | - Alexander Dobrovic
- Molecular Pathology Research and Development Laboratory, Department of Pathology, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, Melbourne, Victoria, 8006, Australia
- Department of Pathology, The University of Melbourne, Parkville, Victoria, 3010, Australia
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19
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Mikula I, Mikula I. Characterization of ovine Toll-like receptor 9 protein coding region, comparative analysis, detection of mutations and maedi visna infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:182-192. [PMID: 20875448 DOI: 10.1016/j.dci.2010.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 09/16/2010] [Accepted: 09/17/2010] [Indexed: 05/29/2023]
Abstract
One of the major roles of innate immunity system is the recognition and the determination of the nature of the antigen. This ability is encompassed by specific receptors as Toll-like receptors (TLRs). TLR9 recognizes bacterial and viral CpG motifs, while their potent immunostimulation effect seems to be promising for lentiviral therapies. Recent studies, however, show the presence of a big polymorphism within the TLR genes and the linkage between substitutions and susceptibility to various infections. Moreover, different recognition ability seems to be utilized by different species and possibly breeds. In this study, we characterized the protein coding region of ovine TLR9 gene. By using comparative analysis of two closely related species and humans, we suggest, which characteristics of protein could be responsible for altered recognition. Furthermore, analyzing the presence of the substitutions, we show the intraspecies polymorphism and its possible implications, while attempting to define the association of discovered substitutions with the maedi visna infection.
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Affiliation(s)
- Ivan Mikula
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenskeho - 73, 041 81 Kosice, Slovakia.
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20
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Wyatt AW, Osborne RJ, Stewart H, Ragge NK. Bone morphogenetic protein 7 (BMP7) mutations are associated with variable ocular, brain, ear, palate, and skeletal anomalies. Hum Mutat 2010; 31:781-7. [PMID: 20506283 DOI: 10.1002/humu.21280] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Bone morphogenetic protein (BMP) signaling regulates a range of cellular processes and plays an important role in the specification and patterning of the early embryo. However, due to the functional redundancy of BMP ligands and receptors in tissues where they are coexpressed, relatively little is known about the role of individual BMP ligands in human disease. Here we report heterozygous variations in BMP7, including a frameshift, missense, and Kozak sequence mutation, in individuals with developmental eye anomalies and a range of systemic abnormalities, including developmental delay, deafness, scoliosis, and cleft palate. We determined that BMP7 is expressed in the developing eye, brain, and ear in human embryos in a manner consistent with the phenotype seen in our mutation cases. These data establish BMP7 as an important gene in human eye development, and suggest that BMP7 should be considered during clinical evaluation of individuals with developmental eye anomalies.
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Affiliation(s)
- Alexander W Wyatt
- Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
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21
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Montgomery JL, Sanford LN, Wittwer CT. High-resolution DNA melting analysis in clinical research and diagnostics. Expert Rev Mol Diagn 2010; 10:219-40. [PMID: 20214540 DOI: 10.1586/erm.09.84] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Among nucleic acid analytical methods, high-resolution melting analysis is gaining more and more attention. High-resolution melting provides simple, homogeneous solutions for variant scanning and genotyping, addressing the needs of today's overburdened laboratories with rapid turnaround times and minimal cost. The flexibility of the technique has allowed it to be adopted by a wide range of disciplines for a variety of applications. In this review we examine the broad use of high-resolution melting analysis, including gene scanning, genotyping (including small amplicon, unlabeled probe and snapback primers), sequence matching and methylation analysis. Four major application arenas are examined to demonstrate the methods and approaches commonly used in particular fields. The appropriate usage of high-resolution melting analysis is discussed in the context of known constraints, such as sample quality and quantity, with a particular focus placed on proper experimental design in order to produce successful results.
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Affiliation(s)
- Jesse L Montgomery
- Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
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22
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Mikula I, Bhide M, Pastorekova S, Mikula I. Characterization of ovine TLR7 and TLR8 protein coding regions, detection of mutations and Maedi Visna virus infection. Vet Immunol Immunopathol 2010; 138:51-9. [PMID: 20638136 DOI: 10.1016/j.vetimm.2010.06.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 06/15/2010] [Accepted: 06/21/2010] [Indexed: 11/30/2022]
Abstract
Toll-like receptors (TLRs) 2, 3, 4, 7, 8 and 9 play a crucial role in the recognition of viral entities and modulation of the innate immune system. This work presents sequence analysis of ovine TLR7 and TLR8 genes, depicts novel mutations and describes frequencies of mutations in Maedi Visna infected and healthy sheep. Totally 48 samples of the breed Tsigai were analyzed for the presence of mutations. Within 20 mutations, 14 were silent whereas 6 were missense. The frequencies of missense mutations in the Maedi Visna infected compared to non-infected sheep were: Lys115Glu (P-0.766, F-test), Asn117 (P-0.380) and Lys818Arg (P-0.739). These three mutations were localized in extra LRR (lucine rich repeat) region of TLR7, while mutation Ile73Leu (P-0.498) was located within LRR2 motif. Both mutations in TLR8, Asn165Lys (P-1.0) and Tyr349His (P-0.700), were present in extra LRR region. The secondary structure analysis of ovine TLR7 and TLR8 revealed conserved LRR motif structure, however with some irregularities compared to cattle and human. Transmembrane domains of TLR7 and TLR8 showed 100% homology between sheep and cattle wherein no mutations were found. In both TLRs TIR domains were highly conserved with occurrence of 4 silent mutations. Mutations in TLR7 and TLR8 may play an important role as predisposition factor for Maedi Visna infection. Considering the sequence homology among sheep, cattle and human genes encoding TLR7 and TLR8, we predict their similar function, localization and downstream signaling.
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Affiliation(s)
- Ivan Mikula
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenskeho-73, Kosice, Slovakia
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23
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Chiu C, Bagnall RD, Ingles J, Yeates L, Kennerson M, Donald JA, Jormakka M, Lind JM, Semsarian C. Mutations in alpha-actinin-2 cause hypertrophic cardiomyopathy: a genome-wide analysis. J Am Coll Cardiol 2010; 55:1127-35. [PMID: 20022194 DOI: 10.1016/j.jacc.2009.11.016] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 09/23/2009] [Accepted: 11/09/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES This study describes a genome-wide linkage analysis of a large family with clinically heterogeneous hypertrophic cardiomyopathy (HCM). BACKGROUND Familial HCM is a disorder characterized by genetic heterogeneity. In as many as 50% of HCM cases, the genetic cause remains unknown, suggesting that other genes may be involved. METHODS Clinical evaluation, including clinical history, physical examination, electrocardiography, and 2-dimensional echocardiography, was performed, and blood was collected from family members (n = 23) for deoxyribonucleic acid analysis. The family was genotyped with markers from the 10-cM AB PRISM Human Linkage mapping set (Applied Biosystems, Foster City, California), and 2-point linkage analysis was performed. RESULTS Affected family members showed marked clinical diversity, ranging from asymptomatic individuals to those with syncope, heart failure, and premature sudden death. The disease locus for this family was mapped to chromosome 1q42.2-q43, near the marker D1S2850 (logarithm of odds ratio = 2.82, theta = 0). A missense mutation, Ala119Thr, in the alpha-actinin-2 (ACTN2) gene was identified that segregated with disease in the family. An additional 297 HCM probands were screened for mutations in the ACTN2 gene using high-resolution melt analysis. Three causative ACTN2 mutations, Thr495Met, Glu583Ala, and Glu628Gly, were identified in an additional 4 families (total 1.7%) with HCM. CONCLUSIONS This is the first genome-wide linkage analysis that shows mutations in ACTN2 cause HCM. Mutations in genes encoding Z-disk proteins account for a small but significant proportion of genotyped HCM families.
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Affiliation(s)
- Christine Chiu
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia
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Dwyer S, Carroll L, Mantripragada KK, Owen MJ, O'Donovan MC, Williams NM. Mutation screening of the DTNBP1 exonic sequence in 669 schizophrenics and 710 controls using high-resolution melting analysis. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:766-74. [PMID: 19859905 DOI: 10.1002/ajmg.b.31045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A large number of independent studies have reported evidence for association between the dysbindin gene (DTNBP1) and schizophrenia; however, specific risk alleles have been not been implicated as causal. In this study we set out to perform a comprehensive assessment of DNA variation within the exonic sequence of DTNBP1. To achieve this we optimized a high-resolution melting analysis (HRMA) protocol and applied it to screen all 11 DTNBP1 exons for DNA variants in a sample of 669 cases and 710 controls from the UK. Despite identifying seven exonic variants with a minor allele frequency (MAF) >0.01, none was significantly associated with schizophrenia (minimum P = 0.054), showing that the strong association we previously reported in this sample is not the result of association to a common functional variant located within the exonic sequence of any of the three major DTNBP1 transcripts. We also sought additional support for DTNBP1 as a susceptibility gene for schizophrenia by testing the hypothesis that rare exonic highly penetrant variants exist at the DTNBP1 locus. Our analysis failed to identify an enrichment of rare functional variants in the patients compared to the controls. Taken as a whole, this data demonstrate that if DTNBP1 is a risk gene for schizophrenia then risk is not conferred by mutations that affect the structure of the dysbindin protein.
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Affiliation(s)
- S Dwyer
- MRC Centre for Neuropsychiatric Genetics and Genomics, Department of Psychological Medicine and Neurology, Cardiff University, Cardiff, UK
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25
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Davies JS, Chung SK, Thomas RH, Robinson A, Hammond CL, Mullins JGL, Carta E, Pearce BR, Harvey K, Harvey RJ, Rees MI. The glycinergic system in human startle disease: a genetic screening approach. Front Mol Neurosci 2010; 3:8. [PMID: 20407582 PMCID: PMC2854534 DOI: 10.3389/fnmol.2010.00008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 03/08/2010] [Indexed: 11/17/2022] Open
Abstract
Human startle disease, also known as hyperekplexia (OMIM 149400), is a paroxysmal neurological disorder caused by defects in glycinergic neurotransmission. Hyperekplexia is characterised by an exaggerated startle reflex in response to tactile or acoustic stimuli which first presents as neonatal hypertonia, followed in some with episodes of life-threatening infantile apnoea. Genetic screening studies have demonstrated that hyperekplexia is genetically heterogeneous with several missense and nonsense mutations in the postsynaptic glycine receptor (GlyR) alpha1 subunit gene (GLRA1) as the primary cause. More recently, missense, nonsense and frameshift mutations have also been identified in the glycine transporter GlyT2 gene, SLC6A5, demonstrating a presynaptic component to this disease. Further mutations, albeit rare, have been identified in the genes encoding the GlyR beta subunit (GLRB), collybistin (ARHGEF9) and gephyrin (GPHN) - all of which are postsynaptic proteins involved in orchestrating glycinergic neurotransmission. In this review, we describe the clinical ascertainment aspects, phenotypic considerations and the downstream molecular genetic tools utilised to analyse both presynaptic and postsynaptic components of this heterogeneous human neurological disorder. Moreover, we will describe how the ancient startle response is the preserve of glycinergic neurotransmission and how animal models and human hyperekplexia patients have provided synergistic evidence that implicates this inhibitory system in the control of startle reflexes.
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Affiliation(s)
- Jeff S Davies
- Institute of Life Science, School of Medicine, Swansea University Singleton Park, Swansea, UK
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26
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Brewer MH, Chaudhry R, McDowall K, Chu S, Kowalski B, Polly P, Nicholson G, Kennerson M. X-linked CMT: genes and gene loci in an Australian cohort. Neurogenetics 2010; 11:267-9. [PMID: 20204443 DOI: 10.1007/s10048-010-0238-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 02/18/2010] [Indexed: 10/19/2022]
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Tindall EA, Petersen DC, Woodbridge P, Schipany K, Hayes VM. Assessing high-resolution melt curve analysis for accurate detection of gene variants in complex DNA fragments. Hum Mutat 2009; 30:876-83. [PMID: 19280649 DOI: 10.1002/humu.20919] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mutation detection has, until recently, relied heavily on the use of gel-based methods that can be both time consuming and difficult to design. Nongel-based systems are therefore important to increase simplicity and improve turn around time without compromising assay sensitivity and accuracy, especially in the diagnostic/clinical setting. In this study, we assessed the latest of the nongel-based methods, namely high-resolution melt (HRM) curve analysis. HRM is a closed-tube method that incorporates a saturating dye during DNA amplification followed by a monitoring of the change in fluorescence as the DNA duplex is denatured by an increasing temperature. We assessed 10 amplicons derived from eight genes, namely SERPINA1, CXCR7, MBL, VDR, NKX3A, NPY, TP53, and HRAS using two platforms, the LightScanner System using LC Green PLUS DNA binding dye (Idaho Technology, Salt Lake City, UT, USA) and the LightCycler 480 using the HRM Master dye (Roche Diagnostics, Indianapolis, IN, USA). DNA variants (mutations or polymorphims) were previously identified using denaturing gradient gel electrophoresis (DGGE) a method, similarly to HRM, based upon the different melting properties of double-stranded DNA. Fragments were selected based on variant and fragment complexity. This included the presence of multiple sequence variants, variants in alternate orientations, and single or multiple variants (constitutional or somatic) in GC-rich fragments. We demonstrate current limitations of the HRM method for the analysis of complex DNA regions and call for caution when using HRM as the sole method to make a clinical diagnosis based on genetic analysis.
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Affiliation(s)
- Elizabeth A Tindall
- Cancer Genetics Group, Children's Cancer Institute Australia for Medical Research, Sydney Children's Hospital, Randwick, Sydney, NSW, Australia
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28
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Abstract
Mutation scanning techniques are used to detect sequence variants without the need for prior knowledge of the identity or precise location of the variant, in contrast with genotyping techniques, which determine the status of a specific variant. High-resolution melting is a recently developed method that shows great potential as a mutation scanning technique. Sensitivity and specificity for mutation detection are extremely high and the technique also has advantages of cost and throughput. Practical considerations for successful mutation scanning by high-resolution melting are also discussed in this review.
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Identification of fibrillin-1 gene mutations in Marfan syndrome by high-resolution melting analysis. Anal Biochem 2009; 389:102-6. [PMID: 19328768 DOI: 10.1016/j.ab.2009.03.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 03/23/2009] [Accepted: 03/23/2009] [Indexed: 01/15/2023]
Abstract
Marfan syndrome has been associated with approximately 562 mutations in the fibrillin-1 (FBN1) gene. Mutation scanning of the FBN1 gene with DNA direct sequencing is time-consuming and expensive because of its large size. This study analyzed the diagnostic value of high-resolution melting analysis as an alternative method for scanning of the FBN1 gene. A total of 75 polymerase chain reaction (PCR) amplicons (179-301bp, average 256bp) that covered the complete coding regions and splicing sites were evaluated on the 96-well LightCycler system. Melting curves were analyzed as fluorescence derivative plots (-dF/dT vs. temperature). To determine the sensitivity of this method, a total of 82 samples from patients with Marfan syndrome and 50 unaffected individuals were analyzed. All mutations reported in this study had been confirmed previously by direct sequencing analysis. Melting analysis identified 48 heterozygous variants. The variant c.3093 G>T (exon 25) was incorrectly identified by melting curve analysis. The sensitivity of the technique in this sample was 98.78% (81/82). This study demonstrated that high-resolution melting analysis is a reliable gene scanning method with greater speed than DNA sequencing. Our results support the use of this technology as an alternative method for the diagnosis of Marfan syndrome as well as its suitability for high-throughput mutation scanning of other large genes.
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Xiao J, Bastian RW, Perlmutter JS, Racette BA, Tabbal SD, Karimi M, Paniello RC, Blitzer A, Batish SD, Wszolek ZK, Uitti RJ, Hedera P, Simon DK, Tarsy D, Truong DD, Frei KP, Pfeiffer RF, Gong S, Zhao Y, LeDoux MS. High-throughput mutational analysis of TOR1A in primary dystonia. BMC MEDICAL GENETICS 2009; 10:24. [PMID: 19284587 PMCID: PMC2661056 DOI: 10.1186/1471-2350-10-24] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Accepted: 03/11/2009] [Indexed: 01/05/2023]
Abstract
Background Although the c.904_906delGAG mutation in Exon 5 of TOR1A typically manifests as early-onset generalized dystonia, DYT1 dystonia is genetically and clinically heterogeneous. Recently, another Exon 5 mutation (c.863G>A) has been associated with early-onset generalized dystonia and some ΔGAG mutation carriers present with late-onset focal dystonia. The aim of this study was to identify TOR1A Exon 5 mutations in a large cohort of subjects with mainly non-generalized primary dystonia. Methods High resolution melting (HRM) was used to examine the entire TOR1A Exon 5 coding sequence in 1014 subjects with primary dystonia (422 spasmodic dysphonia, 285 cervical dystonia, 67 blepharospasm, 41 writer's cramp, 16 oromandibular dystonia, 38 other primary focal dystonia, 112 segmental dystonia, 16 multifocal dystonia, and 17 generalized dystonia) and 250 controls (150 neurologically normal and 100 with other movement disorders). Diagnostic sensitivity and specificity were evaluated in an additional 8 subjects with known ΔGAG DYT1 dystonia and 88 subjects with ΔGAG-negative dystonia. Results HRM of TOR1A Exon 5 showed high (100%) diagnostic sensitivity and specificity. HRM was rapid and economical. HRM reliably differentiated the TOR1A ΔGAG and c.863G>A mutations. Melting curves were normal in 250/250 controls and 1012/1014 subjects with primary dystonia. The two subjects with shifted melting curves were found to harbor the classic ΔGAG deletion: 1) a non-Jewish Caucasian female with childhood-onset multifocal dystonia and 2) an Ashkenazi Jewish female with adolescent-onset spasmodic dysphonia. Conclusion First, HRM is an inexpensive, diagnostically sensitive and specific, high-throughput method for mutation discovery. Second, Exon 5 mutations in TOR1A are rarely associated with non-generalized primary dystonia.
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Affiliation(s)
- Jianfeng Xiao
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN, USA.
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Abstract
LightCycler technology combines rapid-cycle polymerase chain reaction with real-time fluorescent monitoring and melting curve analysis. Since its introduction in 1997, it is now used in many areas of molecular pathology, including oncology (solid tumors and hematopathology), inherited disease, and infectious disease. By monitoring product accumulation during rapid amplification, quantitative polymerase chain reaction in a closed-tube system is possible in 15 to 30 minutes. Furthermore, melting curve analysis of probes and/or amplicons provides genotyping and even haplotyping. Novel mutations are identified by unexpected melting temperature or curve shape changes. Melting probe designs include adjacent hybridization probes, single labeled probes, unlabeled probes, and snapback primers. High-resolution melting allows mutation scanning by detecting all heterozygous changes. This review describes the major advances throughout the last 15 years regarding LightCycler technology and its application in clinical laboratories.
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Affiliation(s)
- Elaine Lyon
- Department of Pathology, University of Utah, Salt Lake City, Utah, USA.
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Pichler M, Balic M, Stadelmeyer E, Ausch C, Wild M, Guelly C, Bauernhofer T, Samonigg H, Hoefler G, Dandachi N. Evaluation of high-resolution melting analysis as a diagnostic tool to detect the BRAF V600E mutation in colorectal tumors. J Mol Diagn 2009; 11:140-7. [PMID: 19213871 DOI: 10.2353/jmoldx.2009.080100] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BRAF V600E is the predominantly occurring mutation of the cytoplasmic kinase BRAF, and, in colorectal cancer, its determination provides a diagnostic exclusion criterion for hereditary nonpolyposis colorectal cancer. The aim of our study was to develop a sensitive BRAF V600E high resolution melting (HRM) assay. We first established and optimized the BRAF HRM assay using a cell line dilution model, enabling us to detect 1% mutant DNA in a background of wild-type DNA. In a comparison, DNA sequencing and real-time allele-specific PCR in the cell line dilution model HRM assay proved to be more sensitive than DNA sequencing and denaturing high performance liquid chromatography, retaining the same sensitivity as real-time allele-specific PCR. In a learning set of 13 patients with known BRAF V600 status, the mutation was detected with high concordance by all four methods. Finally, we validated the HRM assay on 60 formalin-fixed, paraffin-embedded colorectal cancer samples. Although all mutated samples were correctly identified by HRM, the detection limit of the HRM assay decreased when using low-quality DNA derived from formalin-fixed, paraffin-embedded samples. In conclusion, HRM analysis is a powerful diagnostic tool for detection of BRAF V600E mutation with a high sensitivity and high-throughput capability. Despite the expected decrease in sensitivity, HRM can reliably be applied in archival formalin-fixed, paraffin-embedded samples tissues.
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Affiliation(s)
- Martin Pichler
- Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria
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Kennerson M, Nicholson G, Kowalski B, Krajewski K, El-Khechen D, Feely S, Chu S, Shy M, Garbern J. X-linked distal hereditary motor neuropathy maps to the DSMAX locus on chromosome Xq13.1-q21. Neurology 2009; 72:246-52. [PMID: 19153371 DOI: 10.1212/01.wnl.0000339483.86094.a5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To clinically characterize and map the gene locus in a three-generation family with an X-linked adult-onset distal hereditary motor neuropathy. METHODS Microsatellite markers spanning the juvenile distal spinal muscular atrophy (DSMAX) locus were genotyped and analyzed using genetic linkage analysis. The promoter, untranslated and coding region of the gap junction beta1 (GJB1) gene was sequenced. Nine positional candidate genes were screened for disease mutations using high-resolution melt (HRM) analysis. RESULTS The family showed significant linkage to markers on chromosome Xq13.1-q21. Haplotype construction revealed a disease-associated haplotype between the markers DXS991 and DX5990. Sequence analysis excluded pathogenic changes in the coding and promoter regions of the GJB1 gene. Additional fine mapping in the family refined the DSMAX locus to a 1.44-cM interval between DXS8046 and DXS8114. HRM analysis did not identify disease-associated mutations in the coding region of nine candidate genes. CONCLUSION We have identified a family with adult-onset distal hereditary motor neuropathy that refines the locus reported for juvenile distal spinal muscular atrophy (DSMAX) on chromosome Xq13.1-q21. Exclusion of mutations in the coding and regulatory region of the GJB1 gene eliminated the CMTX1 locus as a cause of disease in this family. Nine positional candidate genes in the refined interval underwent mutation analysis and were eliminated as the pathogenic cause of DSMAX in this family. The syndrome in this family may be allelic to the juvenile distal spinal muscular atrophy first reported at this locus.
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Affiliation(s)
- M Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia.
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Wu SB, Wirthensohn MG, Hunt P, Gibson JP, Sedgley M. High resolution melting analysis of almond SNPs derived from ESTs. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2008; 118:1-14. [PMID: 18781291 DOI: 10.1007/s00122-008-0870-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2008] [Accepted: 08/15/2008] [Indexed: 05/22/2023]
Abstract
High resolution melting curve (HRM) is a recent advance for the detection of SNPs. The technique measures temperature induced strand separation of short PCR amplicons, and is able to detect variation as small as one base difference between samples. It has been applied to the analysis and scan of mutations in the genes causing human diseases. In plant species, the use of this approach is limited. We applied HRM analysis to almond SNP discovery and genotyping based on the predicted SNP information derived from the almond and peach EST database. Putative SNPs were screened from almond and peach EST contigs by HRM analysis against 25 almond cultivars. All 4 classes of SNPs, INDELs and microsatellites were discriminated, and the HRM profiles of 17 amplicons were established. The PCR amplicons containing single, double and multiple SNPs produced distinctive HRM profiles. Additionally, different genotypes of INDEL and microsatellite variations were also characterised by HRM analysis. By sequencing the PCR products, 100 SNPs were validated/revealed in the HRM amplicons and their flanking regions. The results showed that the average frequency of SNPs was 1:114 bp in the genic regions, and transition to transversion ratio was 1.16:1. Rare allele frequencies of the SNPs varied from 0.02 to 0.5, and the polymorphic information contents of the SNPs were from 0.04 to 0.53 at an average of 0.31. HRM has been demonstrated to be a fast, low cost, and efficient approach for SNP discovery and genotyping, in particular, for species without much genomic information such as almond.
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Affiliation(s)
- Shu-Biao Wu
- School of Environmental and Rural Science and The Institute of Genetics and Bioinformatics, The University of New England, Armidale, NSW, 2351, Australia.
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Sestini R, Provenzano A, Bacci C, Orlando C, Genuardi M, Papi L. NF2 mutation screening by denaturing high-performance liquid chromatography and high-resolution melting analysis. ACTA ACUST UNITED AC 2008; 12:311-8. [PMID: 18554169 DOI: 10.1089/gte.2007.0096] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Neurofibromatosis type 2 (NF2) is an autosomal-dominant disorder caused by mutations in the NF2 gene and predisposing to the development of nervous system. Identification of germline mutations is essential to provide appropriate genetic counseling in NF2 patients, but it represents an extremely challenging task because the vast majority of mutations are unique and spread over the entire coding sequence. Moreover, about 30% of de novo patients are indeed mosaic, and direct sequencing can undetect mutated alleles present in a minority of cells. As most screening techniques do not meet the requirements for efficient NF2 testing, we have developed a semi-automated denaturing high-performance liquid chromatography (DHPLC) method for point mutation detection combined with a multiplex ligation-dependent probe amplification approach to screen for gene rearrangements. In addition, we have evaluated high-resolution melting analysis (HRMA) as an exon scanning procedure to identify point mutations in the NF2 gene. The results obtained in 92 NF2 patients expand the NF2 mutational spectrum and indicate DHPLC and HRMA as good systems to screen for point mutations in diseases with a heterogeneous spectrum of alterations.
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Affiliation(s)
- Roberta Sestini
- Department of Clinical Physiopathology, Medical Genetics Unit, University of Florence, Firenze, Italy.
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de Juan I, Esteban E, Palanca S, Barragán E, Bolufer P. High-resolution melting analysis for rapid screening of BRCA1 and BRCA2 Spanish mutations. Breast Cancer Res Treat 2008; 115:405-14. [PMID: 18528753 DOI: 10.1007/s10549-008-0073-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Accepted: 05/19/2008] [Indexed: 01/01/2023]
Abstract
The majority of BRCA1 and BRCA2 mutation detection procedures include screening methods, all of which are time-consuming. High-resolution melting (HRM) is a promising pre-screening method of gene scanning that combines simplicity and rapid identification of genetic variants. We evaluated HRM in the screening of BRCA1/2 Spanish mutations. We studied 40 BRCA1 and 47 BRCA2 DNA samples with different Spanish mutations. We included a group of 20 unknown DNAs from patients with sporadic breast cancer (BC). The assay was performed with the LightCycler 480 Instrument (Roche). The HRM discriminates all the BRCA1/2 Spanish mutations studied from wild-type DNA. Besides, 54 out of 87 mutations were clearly differentiated from each other. In sporadic BC 11 polymorphisms and three unclassified variants were found in both genes. HRM is a valuable method for rapid screening of BRCA1/2 Spanish mutations and is capable of differentiating new genetic variants in PCR products.
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Affiliation(s)
- Inmaculada de Juan
- Laboratory of Molecular Biology, University Hospital La Fe, Avd. Campanar 21, Valencia 46009, Spain
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De Leeneer K, Coene I, Poppe B, De Paepe A, Claes K. Rapid and Sensitive Detection of BRCA1/2 Mutations in a Diagnostic Setting: Comparison of Two High-Resolution Melting Platforms. Clin Chem 2008; 54:982-9. [PMID: 18403564 DOI: 10.1373/clinchem.2007.098764] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract
Background: High-resolution melting is an emerging technique for detection of nucleic acid sequence variations. Developments in instrumentation and saturating intercalating dyes have made accurate high-resolution melting analysis possible and created opportunities to use this technology in diagnostic settings. We evaluated 2 high-resolution melting instruments for screening BRCA1 and BRCA2 mutations.
Methods: To cover the complete coding region and splice sites, we designed 112 PCR amplicons (136–435 bp), amplifiable with a single PCR program. LCGreen® Plus was used as the intercalating dye. High-resolution melting analysis was performed on the 96-well Lightscanner™ (Idaho Technology Inc.) and the 96-well LightCycler® 480 (Roche) instruments. We evaluated sensitivity by analyzing 212 positive controls scattered over almost all amplicons and specificity by blind screening of 22 patients for BRCA1 and BRCA2. In total, we scanned 3521 fragments.
Results: All 212 known heterozygous sequence variants were detected on the Lightscanner by analysis on normal sensitivity setting. On the LightCycler 480, the standard instrument sensitivity setting of 0.3 had to be increased to 0.7 to detect all variants, decreasing the specificity to 95.9% (vs 98.7% for the Lightscanner).
Conclusions: Previously, we screened BRCA1/2 by direct sequencing of the large exon 11 and denaturing gel gradient electrophoresis (DGGE) for all other coding exons. Since the introduction of high-resolution melting, our turnaround time has been one third of that with direct sequencing and DGGE, as post-PCR handling is no longer required and the software allows fast analyses. High-resolution melting is a rapid, cost-efficient, sensitive method simple enough to be readily implemented in a diagnostic laboratory.
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Affiliation(s)
- Kim De Leeneer
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Ilse Coene
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Bruce Poppe
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Anne De Paepe
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Kathleen Claes
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
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Evidence of a founder haplotype refines the X-linked Charcot-Marie-Tooth (CMTX3) locus to a 2.5 Mb region. Neurogenetics 2008; 9:191-5. [PMID: 18458969 DOI: 10.1007/s10048-008-0126-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Accepted: 02/29/2008] [Indexed: 10/22/2022]
Abstract
X-linked Charcot-Marie-Tooth (CMTX) disease is a common inherited degenerative disorder of the peripheral nerve. Previously, our laboratory identified a large New Zealand/United Kingdom (NZ/UK) family mapping to the CMTX3 locus (Xq26.3-27.1). We have now identified a second large, Australian X-linked CMT family that links to the CMTX3 locus. This new family has the same phenotype as our previously described CMTX3 family, with slightly milder disease in males than CMTX1 and asymptomatic carrier females. This study also includes the re-analysis of one of the original US pedigrees reporting the CMTX3 locus. The large Australian family shared the complete disease haplotype with our original NZ/UK family, while the American family shared only the distal portion of the disease haplotype. Comparison of the frequency of the CMTX3 haplotype to the normal population showed strong statistical evidence (p < 0.0001) indicating that the smaller shared haplotype is identical by descent. This suggests that the new CMTX3 family, our previously reported family, and the original American CMTX3 family have a common ancestor, and the disease in these families is caused by a founder mutation. The ancestral recombination observed in the American family refines the CMTX3 interval to a 2.5 Mb region between DXS984 and DXS8106. In this region, 11 out of the 15 annotated genes have been excluded for pathogenic mutations.
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Takano EA, Mitchell G, Fox SB, Dobrovic A. Rapid detection of carriers with BRCA1 and BRCA2 mutations using high resolution melting analysis. BMC Cancer 2008; 8:59. [PMID: 18298804 PMCID: PMC2266761 DOI: 10.1186/1471-2407-8-59] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Accepted: 02/25/2008] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Germline inactivating mutations in BRCA1 and BRCA2 underlie a major proportion of the inherited predisposition to breast and ovarian cancer. These mutations are usually detected by DNA sequencing. Cost-effective and rapid methods to screen for these mutations would enable the extension of mutation testing to a broader population. High resolution melting (HRM) analysis is a rapid screening methodology with very low false negative rates. We therefore evaluated the use of HRM as a mutation scanning tool using, as a proof of principle, the three recurrent BRCA1 and BRCA2 founder mutations in the Ashkenazi Jewish population in addition to other mutations that occur in the same regions. METHODS We designed PCR amplicons for HRM scanning of BRCA1 exons 2 and 20 (carrying the founder mutations185delAG and 5382insC respectively) and the part of the BRCA2 exon 11 carrying the 6174delT founder mutation. The analysis was performed on an HRM-enabled real time PCR machine. RESULTS We tested DNA from the peripheral blood of 29 individuals heterozygous for known mutations. All the Ashkenazi founder mutations were readily identified. Other mutations in each region that were also readily detected included the recently identified Greek founder mutation 5331G>A in exon 20 of BRCA1. Each mutation had a reproducible melting profile. CONCLUSION HRM is a simple and rapid scanning method for known and unknown BRCA1 and BRCA2 germline mutations that can dramatically reduce the amount of sequencing required and reduce the turnaround time for mutation screening and testing. In some cases, such as tracking mutations through pedigrees, sequencing may only be necessary to confirm positive results. This methodology will allow for the economical screening of founder mutations not only in people of Ashkenazi Jewish ancestry but also in other populations with founder mutations such as Central and Eastern Europeans (BRCA1 5382insC) and Greek Europeans (BRCA1 5331G>A).
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Affiliation(s)
- Elena A Takano
- Molecular Pathology Research and Development Laboratory, Department of Pathology, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, Melbourne, Victoria 8006, Australia.
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Reed GH, Kent JO, Wittwer CT. High-resolution DNA melting analysis for simple and efficient molecular diagnostics. Pharmacogenomics 2008; 8:597-608. [PMID: 17559349 DOI: 10.2217/14622416.8.6.597] [Citation(s) in RCA: 444] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
High-resolution melting of DNA is a simple solution for genotyping, mutation scanning and sequence matching. The melting profile of a PCR product depends on its GC content, length, sequence and heterozygosity and is best monitored with saturating dyes that fluoresce in the presence of double-stranded DNA. Genotyping of most variants is possible by the melting temperature of the PCR products, while all variants can be genotyped with unlabeled probes. Mutation scanning and sequence matching depend on sequence differences that result in heteroduplexes that change the shape of the melting curve. High-resolution DNA melting has several advantages over other genotyping and scanning methods, including an inexpensive closed tube format that is homogenous, accurate and rapid. Owing to its simplicity and speed, the method is a good fit for personalized medicine as a rapid, inexpensive method to predict therapeutic response.
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Affiliation(s)
- Gudrun H Reed
- Department of Pathology, University of Utah Medical Center, 5B418, 50 North Medical Drive, Salt Lake City, UT 84132, USA
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Croxford AE, Rogers T, Caligari PDS, Wilkinson MJ. High-resolution melt analysis to identify and map sequence-tagged site anchor points onto linkage maps: a white lupin (Lupinus albus) map as an exemplar. THE NEW PHYTOLOGIST 2008; 180:594-607. [PMID: 18684160 DOI: 10.1111/j.1469-8137.2008.02588.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
* The provision of sequence-tagged site (STS) anchor points allows meaningful comparisons between mapping studies but can be a time-consuming process for nonmodel species or orphan crops. * Here, the first use of high-resolution melt analysis (HRM) to generate STS markers for use in linkage mapping is described. This strategy is rapid and low-cost, and circumvents the need for labelled primers or amplicon fractionation. * Using white lupin (Lupinus albus, x = 25) as a case study, HRM analysis was applied to identify 91 polymorphic markers from expressed sequence tag (EST)-derived and genomic libraries. Of these, 77 generated STS anchor points in the first fully resolved linkage map of the species. The map also included 230 amplified fragment length polymorphisms (AFLP) loci, spanned 1916 cM (84.2% coverage) and divided into the expected 25 linkage groups. * Quantitative trait loci (QTL) analyses performed on the population revealed genomic regions associated with several traits, including the agronomically important time to flowering (tf), alkaloid synthesis and stem height (Ph). Use of HRM-STS markers also allowed us to make direct comparisons between our map and that of the related crop, Lupinus angustifolius, based on the conversion of RFLP, microsatellite and single nucleotide polymorphism (SNP) markers into HRM markers.
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Affiliation(s)
- Adam E Croxford
- Institute of Biological, Environmental and Rural Sciences, Edward Llwyd Building, Aberystwyth University, SY23 3DA, UK
| | - Tom Rogers
- KG Fruits Ltd, Tatlingbury Oast, Five Oak Green, Tonbridge, Kent TN12 6RG, UK
| | - Peter D S Caligari
- Instituto de Biología Vegetal y Biotecnología, Universidad de Talca, 2 Norte 685 Talca, Chile
| | - Michael J Wilkinson
- Institute of Biological, Environmental and Rural Sciences, Edward Llwyd Building, Aberystwyth University, SY23 3DA, UK
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Laurie AD, Smith MP, George PM. Detection of Factor VIII Gene Mutations by High-Resolution Melting Analysis. Clin Chem 2007; 53:2211-4. [PMID: 17901109 DOI: 10.1373/clinchem.2007.093781] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abstract
Background: Single base-pair substitution mutations in the gene for coagulation factor VIII, procoagulant component (hemophilia A) (F8) account for approximately 50% of severe cases of hemophilia A (HA), and almost all moderate or mild cases. Because F8 is a large gene, mutation screening using denaturing HPLC or DNA sequencing is time-consuming and expensive.
Methods: We evaluated high-resolution melting analysis as an option for screening for F8 gene mutations. The melting curves of amplicons heterozygous for known F8 gene mutations were compared with melting curves of the corresponding normal amplicons to assess whether melting analysis could detect these variants. We examined 2 platforms, the Roche LightCycler 480 (LC480) and the Idaho Technology LightScanner.
Results: On both instruments, 18 (90%) of the 20 F8 gene variants we examined were resolved by melting analysis. For the other 2 mutations, the melting curves of the heterozygous amplicons were similar to the corresponding normal amplicons, suggesting these variants may not be detected by this approach in a mutation-scanning screen.
Conclusion: High-resolution melting analysis is an appealing technology for F8 gene screening. It is rapid and quickly identifies mutations in the majority of HA patients; samples in which no mutation is detected require further testing by DNA sequencing. The LC480 and LightScanner platforms performed similarly.
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Affiliation(s)
- Andrew D Laurie
- Department of Molecular Pathology, Canterbury Health Laboratories, Christchurch, New Zealand.
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Vandersteen JG, Bayrak-Toydemir P, Palais RA, Wittwer CT. Identifying Common Genetic Variants by High-Resolution Melting. Clin Chem 2007; 53:1191-8. [PMID: 17525106 DOI: 10.1373/clinchem.2007.085407] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Abstract
Background: Heteroduplex scanning techniques usually detect all heterozygotes, including common variants not of clinical interest.
Methods: We conducted high-resolution melting analysis on the 24 exons of the ACVRL1 and ENG genes implicated in hereditary hemorrhagic telangiectasia (HHT). DNA in samples from 13 controls and 19 patients was PCR amplified in the presence of LCGreen® I, and all 768 exons melted in an HR-1® instrument. We used 10 wild-type controls to identify common variants, and the remaining samples were blinded, amplified, and analyzed by melting curve normalization and overlay. Unlabeled probes characterized the sequence of common variants.
Results: Eleven common variants were associated with 8 of the 24 HHT exons, and 96% of normal samples contained at least 1 variant. As a result, the positive predictive value (PPV) of a heterozygous exon was low (31%), even in a population of predominantly HHT patients. However, all common variants produced unique amplicon melting curves that, when considered and eliminated, resulted in a PPV of 100%. In our blinded study, 3 of 19 heterozygous disease-causing variants were missed; however, 2 were clerical errors, and the remaining false negative would have been identified by difference analysis.
Conclusions: High-resolution melting analysis is a highly accurate heteroduplex scanning technique. With many exons, however, use of single-sample instruments may lead to clerical errors, and routine use of difference analysis is recommended. Common variants can be identified by their melting curve profiles and genotyped with unlabeled probes, greatly reducing the false-positive results common with scanning techniques.
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Affiliation(s)
- Joshua G Vandersteen
- Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
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