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Ortega-Pinazo J, Díaz T, Martínez B, Jiménez A, Pinto-Medel MJ, Ferro P. Quality assessment on the long-term cryopreservation and nucleic acids extraction processes implemented in the andalusian public biobank. Cell Tissue Bank 2019; 20:255-265. [PMID: 30903409 DOI: 10.1007/s10561-019-09764-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/14/2019] [Indexed: 12/11/2022]
Abstract
Human samples are commonly collected and long-term stored in biobanks for current and future analyses. Even though techniques for freezing human blood are well established, the storage time can compromise the cell viability as well as the yield and quality of nucleic acids (RNA and DNA) extracted from them. In this study, a protocol to obtain peripheral blood mononuclear cells (PBMCs) from 70 subjects, which were stored at - 196 °C from EDTA tubes for a long-term, was assessed. In parallel; a protocol to obtain DNA from the same subjects, which were stored at - 80 °C from citrate tubes, was also studied. Samples stored from 2008 to 2012 were studied and the results obtained showed that there were no statistically significant differences in the RNA or DNA extracted in terms of purity, integrity and functionality The freezing protocol used by the Málaga Biobank shows that viable PBMCs and DNA could be kept for a period of, at least, 10 years, with a high quality and performance. Furthermore, RNA extracted from these PBMCs presents also a good quality and performance. Therefore, the samples frozen according to the conditions of the protocols assessed in this study could be optimal for biomedical research.
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Affiliation(s)
- J Ortega-Pinazo
- Neuroscience UGC, Instituto de Investigación Biomédica de Málaga (IBIMA), Sanitary Distric of Málaga, University of Málaga, Málaga, Spain
| | - T Díaz
- Andalusian Public Health System Biobank, Instituto de Investigación Biomédica de Málaga (IBIMA), Sanitary Distric of Málaga, University of Málaga, Málaga, Spain
| | - B Martínez
- Andalusian Public Health System Biobank, Instituto de Investigación Biomédica de Málaga (IBIMA), Sanitary Distric of Málaga, University of Málaga, Málaga, Spain
| | - A Jiménez
- Andalusian Public Health System Biobank, Instituto de Investigación Biomédica de Málaga (IBIMA), Sanitary Distric of Málaga, University of Málaga, Málaga, Spain
| | - M J Pinto-Medel
- Neuroscience UGC, Instituto de Investigación Biomédica de Málaga (IBIMA), Sanitary Distric of Málaga, University of Málaga, Málaga, Spain
| | - P Ferro
- Andalusian Public Health System Biobank, Instituto de Investigación Biomédica de Málaga (IBIMA), Sanitary Distric of Málaga, University of Málaga, Málaga, Spain.
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Bybjerg-Grauholm J, Hagen CM, Khoo SK, Johannesen ML, Hansen CS, Bækvad-Hansen M, Christiansen M, Hougaard DM, Hollegaard MV. RNA sequencing of archived neonatal dried blood spots. Mol Genet Metab Rep 2016; 10:33-37. [PMID: 28053876 PMCID: PMC5198792 DOI: 10.1016/j.ymgmr.2016.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/16/2016] [Accepted: 12/16/2016] [Indexed: 01/25/2023] Open
Abstract
Neonatal dried blood spots (DBS) are routinely collected on standard Guthrie cards for all-comprising national newborn screening programs for inborn errors of metabolism, hypothyroidism and other diseases. In Denmark, the Guthrie cards are stored at − 20 °C in the Danish Neonatal Screening Biobank and each sample is linked to elaborate social and medical registries. This provides a unique biospecimen repository to enable large population research at a perinatal level. Here, we demonstrate the feasibility to obtain gene expression data from DBS using next-generation RNA sequencing (RNA-seq). RNA-seq was performed on five males and five females. Sequencing results have an average of > 30 million reads per sample. 26,799 annotated features can be identified with 64% features detectable without fragments per kilobase of transcript per million mapped reads (FPKM) cutoff; number of detectable features dropped to 18% when FPKM ≥ 1. Sex can be discriminated using blood-based sex-specific gene set identified by the Genotype-Tissue Expression consortium. Here, we demonstrate the feasibility to acquire biologically-relevant gene expression from DBS using RNA-seq which provide a new avenue to investigate perinatal diseases in a high throughput manner.
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Affiliation(s)
- Jonas Bybjerg-Grauholm
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen DK-2300, Denmark; iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Denmark
| | - Christian Munch Hagen
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen DK-2300, Denmark; iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Denmark
| | - Sok Kean Khoo
- Department of Cell and Molecular Biology, Grand Valley State University, Grand Rapids, MI 49503, USA
| | - Maria Louise Johannesen
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen DK-2300, Denmark; iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Denmark
| | - Christine Søholm Hansen
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen DK-2300, Denmark; iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Denmark
| | - Marie Bækvad-Hansen
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen DK-2300, Denmark; iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Denmark
| | - Michael Christiansen
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen DK-2300, Denmark; iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Denmark; Department of Biomedicine, University of Copenhagen, Copenhagen N DK-2200, Denmark
| | - David Michael Hougaard
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen DK-2300, Denmark; iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Denmark
| | - Mads V Hollegaard
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen DK-2300, Denmark; iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Denmark
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Ho NT, Busik JV, Resau JH, Paneth N, Khoo SK. Effect of storage time on gene expression data acquired from unfrozen archived newborn blood spots. Mol Genet Metab 2016; 119:207-213. [PMID: 27553879 PMCID: PMC5083152 DOI: 10.1016/j.ymgme.2016.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 08/13/2016] [Indexed: 01/11/2023]
Abstract
Unfrozen archived newborn blood spots (NBS) have been shown to retain sufficient messenger RNA (mRNA) for gene expression profiling. However, the effect of storage time at ambient temperature for NBS samples in relation to the quality of gene expression data is relatively unknown. Here, we evaluated mRNA expression from quantitative real-time PCR (qRT-PCR) and microarray data obtained from NBS samples stored at ambient temperature to determine the effect of storage time on the quality of gene expression. These data were generated in a previous case-control study examining NBS in 53 children with cerebral palsy (CP) and 53 matched controls. NBS sample storage period ranged from 3 to 16years at ambient temperature. We found persistently low RNA integrity numbers (RIN=2.3±0.71) and 28S/18S rRNA ratios (~0) across NBS samples for all storage periods. In both qRT-PCR and microarray data, the expression of three common housekeeping genes-beta cytoskeletal actin (ACTB), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and peptidylprolyl isomerase A (PPIA)-decreased with increased storage time. Median values of each microarray probe intensity at log2 scale also decreased over time. After eight years of storage, probe intensity values were largely reduced to background intensity levels. Of 21,500 genes tested, 89% significantly decreased in signal intensity, with 13,551, 10,730, and 9925 genes detected within 5years, > 5 to <10years, and >10years of storage, respectively. We also examined the expression of two gender-specific genes (X inactivation-specific transcript, XIST and lysine-specific demethylase 5D, KDM5D) and seven gene sets representing the inflammatory, hypoxic, coagulative, and thyroidal pathways hypothesized to be related to CP risk to determine the effect of storage time on the detection of these biologically relevant genes. We found the gender-specific genes and CP-related gene sets detectable in all storage periods, but exhibited differential expression (between male vs. female or CP vs. control) only within the first six years of storage. We concluded that gene expression data quality deteriorates in unfrozen archived NBS over time and that differential gene expression profiling and analysis is recommended for those NBS samples collected and stored within six years at ambient temperature.
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Affiliation(s)
- Nhan T Ho
- Department of Epidemiology & Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI, USA
| | - Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - James H Resau
- Graduate School, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Nigel Paneth
- Department of Epidemiology & Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI, USA; Department of Pediatrics & Human Development, College of Human Medicine, Michigan State University, East Lansing, MI, USA
| | - Sok Kean Khoo
- Department of Cell and Molecular Biology, Grand Valley State University, Allendale, MI, USA.
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Grauholm J, Khoo SK, Nickolov RZ, Poulsen JB, Bækvad-Hansen M, Hansen CS, Hougaard DM, Hollegaard MV. Gene expression profiling of archived dried blood spot samples from the Danish Neonatal Screening Biobank. Mol Genet Metab 2015. [PMID: 26212339 DOI: 10.1016/j.ymgme.2015.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A large part of the human genome is transcribed into various forms of RNA, and the global gene expression profile (GEP) has been studied for several years using technology such as RNA-microarrays. In this study, we evaluate whether neonatal dried blood spot (DBS) samples stored in the Danish Neonatal Screening Biobank (DNSB) can be used for GEP. This paper is divided into sub-studies examining the effects of: 1) different whole transcriptome amplification kits (WTA); 2) years of storage and storage in room temperature (RT) versus freezers (-20°C) on DNSB DBS samples; 3) effects of RT storage vs freezer storage on DBS samples from the USA and DNSB, and 4) using smaller disc sizes, thereby decreasing DBS use. We present evidence that reliable and reproducible GEPs can be obtained using neonatal DBS samples. The main source of variation is the storage condition. When samples are stored at -20°C, the dynamic range is increased, and Pearson correlations are higher. Differential analysis reveals no statistically significant differences between samples collected a decade apart and stored at -20°C. However, samples stored at RT show differential expression for a third of the gene-specific probes. Our data also suggests that using alternate WTA kits significantly changes the GEP. Finally, the amount of input material, i.e., the size and number of DBS discs used, can be reduced to preserve this valuable and limited material. We conclude that DNSB DBS samples provide a reproducible resource for GEP. Results are improved if the cards are stored at -20°C. Furthermore, it is important to use a single type of kit for analysis because using alternate kits introduces differential expression.
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Affiliation(s)
- Jonas Grauholm
- Section of Neonatal Genetics, Danish Centre for Neonatal Screening, Department of Congenital Diseases, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
| | - Sok Kean Khoo
- Department of Cell and Molecular Biology, Grand Valley State University, Grand Rapids, MI 49503, USA.
| | - Radoslav Z Nickolov
- Department of Mathematics & Computer Science, Fayetteville State University, Fayetteville, NC 28301, USA.
| | - Jesper B Poulsen
- Section of Neonatal Genetics, Danish Centre for Neonatal Screening, Department of Congenital Diseases, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
| | - Marie Bækvad-Hansen
- Section of Neonatal Genetics, Danish Centre for Neonatal Screening, Department of Congenital Diseases, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
| | - Christine S Hansen
- Section of Neonatal Genetics, Danish Centre for Neonatal Screening, Department of Congenital Diseases, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
| | - David M Hougaard
- Danish Centre for Neonatal Screening, Department of Congenital Diseases, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
| | - Mads V Hollegaard
- Section of Neonatal Genetics, Danish Centre for Neonatal Screening, Department of Congenital Diseases, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
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Diallo K, Lehotzky E, Zhang J, Zhou Z, de Rivera IL, Murillo WE, Nkengasong J, Sabatier J, Zhang G, Yang C. Evaluation of a dried blood and plasma collection device, SampleTanker(®), for HIV type 1 drug resistance genotyping in patients receiving antiretroviral therapy. AIDS Res Hum Retroviruses 2014; 30:67-73. [PMID: 23944768 DOI: 10.1089/aid.2013.0127] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Whatman 903 filter paper is the only filter paper that has been used for HIV drug resistance (HIVDR) genotyping in resource-limited settings. In this study, we evaluated another dried blood specimen collection device, termed SampleTanker(®) (ST), for HIVDR genotyping. Blood specimens from 123 antiretroviral therapy (ART)-experienced patients were used to prepare ST whole blood and ST plasma specimens; they were then stored at ambient temperature for 2 or 4 weeks. The remaining plasma specimens were stored at -80°C and used as frozen plasma controls. Frozen plasma viral load (VL) was determined using the Roche Amplicor HIV-1 Monitor test, v.1.5 and 50 specimens with VL ≥3.00 log10 copies/ml were genotyped using the broadly sensitive genotyping assay. The medium VL for the 50 frozen plasma specimens with VL ≥3.00 log10 was 3.58 log10 copies/ml (IQR: 3.32-4.11) and 96.0% (48/50) of them were genotyped. Comparing to frozen plasma specimens, significantly lower genotyping rates were obtained from ST whole blood (48.98% and 42.85%) and ST plasma specimens (36.0% and 36.0%) stored at ambient temperature for 2 and 4 weeks, respectively (p<0.001). Nucleotide sequence identity and resistance profile analyses between the matched frozen plasma and ST whole blood or ST plasma specimens revealed high nucleotide sequence identities and concordant resistance profiles (98.1% and 99.0%, and 96.6% and 98.9%, respectively). Our results indicate that with the current design, the ST may not be the ideal dried blood specimen collection device for HIVDR monitoring for ART patients in resource-limited settings.
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Affiliation(s)
- Karidia Diallo
- International Laboratory Branch, Division of Global HIV/AIDS, CGH, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Erica Lehotzky
- International Laboratory Branch, Division of Global HIV/AIDS, CGH, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jing Zhang
- International Laboratory Branch, Division of Global HIV/AIDS, CGH, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Zhiyong Zhou
- International Laboratory Branch, Division of Global HIV/AIDS, CGH, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Wendy E. Murillo
- National Autonomous University of Honduras (UNAH), Tegucigalpa, Honduras
| | - John Nkengasong
- International Laboratory Branch, Division of Global HIV/AIDS, CGH, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jennifer Sabatier
- Strategic Information and Epidemiology Branch, Division of Global HIV/AIDS, CGH, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Guoqing Zhang
- International Laboratory Branch, Division of Global HIV/AIDS, CGH, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Chunfu Yang
- International Laboratory Branch, Division of Global HIV/AIDS, CGH, Centers for Disease Control and Prevention, Atlanta, Georgia
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Ho NT, Furge K, Fu W, Busik J, Khoo SK, Lu Q, Lenski M, Wirth J, Hurvitz E, Dodge N, Resau J, Paneth N. Gene expression in archived newborn blood spots distinguishes infants who will later develop cerebral palsy from matched controls. Pediatr Res 2013; 73:450-6. [PMID: 23269123 PMCID: PMC4350763 DOI: 10.1038/pr.2012.200] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Gene expression in archived newborn blood spots remaining from newborn screening may reflect pathophysiological disturbances useful in understanding the etiology of cerebral palsy (CP). METHODS We quantified the expression of gene sets representing four physiological pathways hypothesized to contribute to CP in archived unfrozen residual newborn blood spot specimens from 53 children with CP and 53 age-, gender-, and gestational age-matched controls. We selected four empirical and three canonical gene sets representing the inflammatory, hypoxic, coagulative, and thyroidal pathways and examined mRNA expression using an 8 × 60,000 oligonucleotide microarray. The log2 fold change of gene expression between matched cases and controls was analyzed using the generally applicable gene set enrichment method. RESULTS The empirical inflammatory and empirical hypoxic gene sets were significantly downregulated in term-born CP cases (n = 33) as compared with matched controls (P = 0.0007 and 0.0009, respectively), whereas both gene sets were significantly upregulated (P =0.0055 and 0.0223, respectively) in preterm-born CP cases (n = 20). The empirical thyroidal gene set was significantly upregulated in preterm-born CP cases (P = 0.0023). CONCLUSION The newborn blood spot transcriptome can serve as a platform for investigating distinctive gene expression patterns in children who later develop CP.
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Affiliation(s)
- Nhan Thi Ho
- Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI
| | - Kyle Furge
- Laboratory of Computational Biology, Van Andel Research Institute, Grand Rapids, MI
| | - Wenjiang Fu
- Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI
| | - Julia Busik
- Department of Physiology, Michigan State University, East Lansing, MI
| | - Sok Kean Khoo
- Laboratory of Microarray Technology, Program in Biospecimen Science; Van Andel Research Institute, Grand Rapids, MI
| | - Qing Lu
- Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI
| | - Madeleine Lenski
- Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI
| | - Julia Wirth
- Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI
| | - Edward Hurvitz
- Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI
| | | | - James Resau
- Laboratory of Microarray Technology, Program in Biospecimen Science; Van Andel Research Institute, Grand Rapids, MI
| | - Nigel Paneth
- Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI,Department of Pediatrics and Human Development, College of Human Medicine, Michigan State, University, East Lansing, MI
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Identification of the genomic BCR-ABL1 fusion sequence from blood specimen stored on filter paper. Leuk Res 2012; 37:117-9. [PMID: 23127356 DOI: 10.1016/j.leukres.2012.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/01/2012] [Accepted: 10/09/2012] [Indexed: 11/22/2022]
Abstract
Chronic myeloid leukaemia (CML) is characterized by the Philadelphia chromosome resulting in the BCR-ABL1 gene whose mRNA transcript detection is commonly used for diagnosis and monitoring of therapeutic response. However, in collected blood specimen degradation of mRNA has to be considered during storage and transport thus jeopardizing the analysis. We here describe an alternative DNA-based technique applied after long-term blood storage. DNA was isolated from dried blood stains from CML patients stored on filter paper (Guthrie cards) after a median period from diagnosis of 11 years (range: 5-12 years) and analyzed with a two round long-range multiplex PCR (MLR-PCR) to identify the genomic BCR-ABL1 breakpoint. Patient-specific individual BCR-ABL1 fusion sites were successfully detected in 10 out of 13 patients. Dried blood stains represent a valuable resource for genomic DNA analyses. Long term preservation is easily manageable in paper envelopes with the patient's medical files with a minimum of financial costs and efforts. Such the cooperation between laboratories and hospitals separated by long distances is facilitated rendering possible offering specialized genomic analyses to patients with CML virtually everywhere around the world. This technique may also be a valuable approach for diagnostic procedures on a high molecular level in related haematological malignancies.
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Current genetic methodologies in the identification of disaster victims and in forensic analysis. J Appl Genet 2011; 53:41-60. [PMID: 22002120 PMCID: PMC3265735 DOI: 10.1007/s13353-011-0068-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 09/22/2011] [Accepted: 09/23/2011] [Indexed: 12/16/2022]
Abstract
This review presents the basic problems and currently available molecular techniques used for genetic profiling in disaster victim identification (DVI). The environmental conditions of a mass disaster often result in severe fragmentation, decomposition and intermixing of the remains of victims. In such cases, traditional identification based on the anthropological and physical characteristics of the victims is frequently inconclusive. This is the reason why DNA profiling became the gold standard for victim identification in mass-casualty incidents (MCIs) or any forensic cases where human remains are highly fragmented and/or degraded beyond recognition. The review provides general information about the sources of genetic material for DNA profiling, the genetic markers routinely used during genetic profiling (STR markers, mtDNA and single-nucleotide polymorphisms [SNP]) and the basic statistical approaches used in DNA-based disaster victim identification. Automated technological platforms that allow the simultaneous analysis of a multitude of genetic markers used in genetic identification (oligonucleotide microarray techniques and next-generation sequencing) are also presented. Forensic and population databases containing information on human variability, routinely used for statistical analyses, are discussed. The final part of this review is focused on recent developments, which offer particularly promising tools for forensic applications (mRNA analysis, transcriptome variation in individuals/populations and genetic profiling of specific cells separated from mixtures).
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Abstract
The impact of hemoglobinopathies on healthcare in the United States, particularly sickle cell disease (SCD), has been significant. Enactment of the Sickle Cell Anemia Control Act in 1972 significantly increased the federal interest in the SCDs and other hemoglobinopathies. Only since May 1, 2006, have all states required and provided universal newborn screening for SCD despite a national recommendation to this effect in 1987. In this article, we review the history of screening for SCD and other hemoglobinopathies, along with federal and state activities that have contributed to improved health outcomes for patients with SCD, as well as current newborn screening practices. We also chronicle the federal activities that have helped to shape and to refine laboratory screening and diagnostic proficiency. Finally, we review molecular testing strategies that have evolved and outline their possible future impacts on disease detection and outcome improvement.
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Affiliation(s)
- Jane M Benson
- Division of Blood Disorders, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Gauffin F, Nordgren A, Barbany G, Gustafsson B, Karlsson H. Quantitation of RNA decay in dried blood spots during 20 years of storage. Clin Chem Lab Med 2010; 47:1467-9. [PMID: 19863301 DOI: 10.1515/cclm.2009.351] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Diseases with an onset during childhood or adult life can have their origin during fetal life or at birth. Neonatal blood dried on filter paper (Guthrie cards) collected for screening purposes is routinely stored for decades. In addition to clinical use, these filters in combination with patient registers constitute an invaluable resource for epidemiological and pathophysiological research. Although RNA has been successfully recovered from such filters even after decades of storage, the potential decay of RNA over time has not previously been investigated using quantitative methods. METHODS Filter papers (n=5) with dried blood spots from the Swedish National PKU register, stored for 1, 5, 10, 15 or 20 years were randomly selected. RNA was isolated from each sample, quantitated by spectrophotometry and reverse transcribed following DNase I treatment. Amplifiable cDNA was subsequently detected by real-time PCR using primers specific for transcripts encoding beta-actin. RESULTS Transcripts encoding beta-actin were detected in all 25 samples analyzed at a mean threshold cycle (Ct) of 25 (SD 1.9). A one-way ANOVA indicated no significant effect of storage time on Ct values. CONCLUSIONS The lack of significant decay of RNA in dried blood filters stored for up to 20 years suggests that such filters are useful for studies of RNA determinants of diseases with an onset in childhood as well as adult life.
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Affiliation(s)
- Fredrika Gauffin
- Division of Pediatrics, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm, Sweden
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Lira R, Maldonado-Rodriguez A, Rojas-Montes O, Ruiz-Tachiquin M, Torres-Ibarra R, Cano-Dominguez C, Valdez-Salazar H, Gomez-Delgado A, Muñoz O, Alvarez-Muñoz MT. Use of dried blood samples for monitoring hepatitis B virus infection. Virol J 2009; 6:153. [PMID: 19788743 PMCID: PMC2761391 DOI: 10.1186/1743-422x-6-153] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 09/29/2009] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Hepatitis B virus (HBV) infection is a problem in several regions of the world with limited resources. Blood samples dried on filter paper (DBS) have been successfully used to diagnose and monitor several infectious diseases. In Mexico there is an urgent need for an affordable and easy sampling method for viral load (VL) testing and monitoring of chronic HBV infection. The purpose of this work was to validate the utility of DBS samples for monitoring HBV infection in patients from Mexico City. METHODS Matched samples of plasma and DBS on filter paper from 47 HBV infected patients from the Instituto Mexicano del Seguro Social (IMSS), were included. To evaluate the DNA stability and purity from DBS stored at different temperature conditions, samples from ten patients were stored at 4 degree, 25 degree, and 37 degree C for 7 days. After DBS elution and DNA extraction, the purity of these samples was determined measuring the O.D. rate 260/280. The DBS utility for molecular studies was assessed with PCR assays to amplify a 322 bp fragment from the "a" determinant region of the HBV "S" gene. The VL from all samples was determined to evaluate the correlation between plasma and DBS matched samples. RESULTS The quality of the DNA from DBS specimen is not adversely affected by storage at 4 degree, 25 degree and 37 degree C for up 7 days. Statistical ANOVA analyses did not show any significant difference. The same amplification efficiency was observed between DNA templates from samples stored at different temperatures. The Pearson correlation between the VL from DBS and plasma matched samples was 0.93 (p = 0.01). The SD was 1.48 for DBS vs.1.32 for Plasma, and an average of log10 copies/mL of 5.32 vs. 5.53. ANOVA analysis did not show any statistically significant difference between the analyzed groups (p = 0.92). CONCLUSION The results provide strong evidence that the isolation and quantification of DNA-HBV from DBS is a viable alternative for patient monitoring, and molecular characterization of the virus variants circulating in Mexico.
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Affiliation(s)
- Rosalia Lira
- Unidad de Investigacion Medica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Cuauhtemoc 330 Col, Doctores, Delegacion Cuauhtemoc, Mexico City, Mexico.
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Jorgez CJ, Bischoff FZ. Stability of placental RNA using dried maternal blood spots. Reprod Biomed Online 2008; 17:716-21. [PMID: 18983758 DOI: 10.1016/s1472-6483(10)60321-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Having demonstrated successful recovery and detection of placental transcripts from dried blood spots (DBS), various preanalytical conditions were examined to determine optimal handling of samples. The role of several factors was explored, including temperature (4 degrees C versus 25 degrees C), processing time (24 h to 8 weeks), and addition of preservatives (RNA later and formalin) that may interfere with stability and detection of placental transcripts in DBS. mRNA transcripts encoding human glyceraldehyde-3-phosphate dehydrogenase (GAPDH; internal control) and beta-human chorionic gonadotrophin (beta HCG; placental) were analysed by real-time-polymerase chain reaction using DBS from 23 pregnant women. GAPDH and beta HCG transcripts were detected in all samples 24 h after collection. Although treatment of blood with RNA later did not affect RNA recovery, formalin treatment negatively affected RNA recovery from DBS. Temperature did not have a significant effect on levels of either transcript. Storage time caused a significant decrease in GAPDH after 4 weeks (P = 0.014) and beta HCG after 1 week (P = 0.007). Decrease of beta HCG levels after 1 week followed by steady detectable levels for up to 4 weeks suggests two populations of circulating placental transcript exist, a population susceptible to degradation in blood versus a more stable form. Therefore, defining proper parameters for collection and storage of DBS further reinforces reliable analysis of target sequences for clinical testing.
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Affiliation(s)
- Carolina J Jorgez
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA
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Therrell BL, Adams J. Newborn screening in North America. J Inherit Metab Dis 2007; 30:447-65. [PMID: 17643194 DOI: 10.1007/s10545-007-0690-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 05/25/2007] [Accepted: 05/31/2007] [Indexed: 10/23/2022]
Abstract
Newborn screening in North America dates to the early work of Bob Guthrie in the USA. Screening programmes in both the USA and Canada began in the early 1960s, with documented programmes in both countries as early as 1962. Throughout the 1960s and 1970s, many of the screening tests that later became part of routine screening around the world were developed in US and Canadian laboratories, including tests for phenylketonuria, other inborn errors of metabolism, congenital hypothyroidism, congenital adrenal hyperplasia, and haemoglobinopathies. An automated punching machine developed in the USA facilitated screening expansion by significantly reducing sample preparation time and effort. US and Canadian programmes were leaders in applying computerized data management to newborn screening in the 1980s. In the 1990s, DNA and tandem mass spectrometry testing protocols were developed in the USA and applied to newborn screening. US programmes have continually expanded over time, while most Canadian programmes have not. With impetus from private laboratories and professional and consumer groups, many US programmes now screen for more than 50 conditions and there is increased expansion activity in Canada. NBS research in the USA is focused on improving system efficiency and translating other genetic testing to NBS, particularly where new technologies and treatment therapies exist. Although national newborn screening policies do not exist in either Canada or the USA, there are intense efforts to provide uniform access to screening nationwide in both countries. New partnerships between health professionals, consumers and politicians are benefiting the overall screening systems in both countries.
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Affiliation(s)
- Bradford L Therrell
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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15
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Jorgez CJ, Simpson JL, Bischoff FZ. Recovery and amplification of placental RNA from dried maternal blood spots: utility for non-invasive prenatal diagnosis. Reprod Biomed Online 2006; 13:558-61. [PMID: 17007679 DOI: 10.1016/s1472-6483(10)60645-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Methods utilizing circulating cell-free RNA in plasma have clinical applications for cancer and prenatal genetic analysis. Given these potential roles, the feasibility of detecting placental specific RNA in dried maternal blood spots after storage at room temperature for varying lengths of time was investigated. Using real-time polymerase chain reaction (PCR), positive amplification of placental-specific beta-human chorionic gonadotrophin transcripts was demonstrated in nine of 11 dried blood samples from first and second trimester pregnancies stored at room temperature for up to 4 weeks. This work demonstrates feasibility in isolation and amplification of placental mRNA using dried maternal blood spots. With the development of fetal and placental RNA markers, this approach would allow simplified collection, transport, and storage of samples for prenatal genetic diagnosis and pregnancy related complications.
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Affiliation(s)
- Carolina J Jorgez
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA
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Bhardwaj U, Zhang YH, Lorey F, McCabe LL, McCabe ERB. Molecular genetic confirmatory testing from newborn screening samples for the common African-American, Asian Indian, Southeast Asian, and Chinese beta-thalassemia mutations. Am J Hematol 2005; 78:249-55. [PMID: 15795925 DOI: 10.1002/ajh.20269] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
beta-Thalassemia is a serious health problem in the United States, especially in California, due to increased Asian immigration. Neonatal screening by using high-performance liquid chromatography (HPLC) or isoelectric focusing (IEF) may lead to confusion due to interactions of various hemoglobinopathies with beta-thalassemia. Our purpose was to develop single-tube multiplexed PCR assays using original neonatal screening specimens to identify the mutations responsible for beta-thalassemia in order to expedite diagnostic confirmation. Primers were designed for two to six common ethnic-specific mutations using the amplification refractory mutation system (ARMS). This multiplex ARMS approach was standardized using DNA samples with known mutations for beta-thalassemia in those of Asian (Southeast Asian, Chinese, and Asian Indian) and African-American descent. Specimens from African-American neonates were tested for two mutations (-88 and -29); Asian Indians for five mutations (IVSI-1, IVSI-5, codons (Cd) 41/42, Cd 8/9, and 619-bp deletion); Chinese, Taiwanese, and Southeast Asians for seven mutations (Cd 41/42, Cd 17, -28, IVSII-654, Cd 71/72, IVSI-5, and IVSI-1). We identified each of these beta-thalassemia mutations in multiplexed ARMS from positive control samples. We tested 25 anonymized dried blood specimens from neonates who had been diagnosed with beta-thalassemia and who also belonged to these ethnic groups. We detected a mutation specific to the neonate's ethnic group using the ARMS approach in nearly all specimens, and the results were confirmed by sequencing. Multiplexed ARMS for ethnic-specific beta-thalassemia mutations from the original newborn screening dried blood specimens is a rapid and efficient approach for diagnostic confirmation.
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Affiliation(s)
- Urvashi Bhardwaj
- Department of Pediatrics, David Geffen School of Medicine at UCLA and Mattel Children's Hospital at UCLA, Los Angeles, California 90095-1752, USA
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Abstract
Genetic screening utilizes analytical approaches adapted for high throughput to identify carrier and affected individuals in a targeted population. Currently, genetic screening focuses on carrier screening, prenatal screening, and newborn screening. Newborn screening should serve as a model for all genetic screening, with more than forty years of experience and numerous lessons learned. As with all genetic screening, there are policy concerns in newborn screening regarding which disorders and technologies should be selected, and how centralized or decentralized the process to set policy should be. The need to share experiences and develop databases transcends all other policy considerations in genetic screening. The future will see population-based screening for adult-onset disorders. However, there needs to be extensive research to define predictive risk for various ethnocultural groups and to determine effective interventions. Ethical concerns regarding the timing of population screening, as well as the scope of use of information, will need to be resolved if genomic medicine will achieve its promise of a predictive, preventive, and personalized medicine.
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Affiliation(s)
- Linda L McCabe
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles 90095, USA.
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Bauer M, Polzin S, Patzelt D. Quantification of RNA degradation by semi-quantitative duplex and competitive RT-PCR: a possible indicator of the age of bloodstains? Forensic Sci Int 2004; 138:94-103. [PMID: 14642725 DOI: 10.1016/j.forsciint.2003.09.008] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In vitro RNA degradation is a complex and non-linear process which can serve as indicator for the quality and age of stains. We have developed a semi-quantitative duplex reverse transcription-polymerase chain reaction (RT-PCR) assay which, in combination with competitive RT-PCR using an external standard, allows quantification of RNA degradation levels. Using this method, we have investigated 106 bloodstains stored up to 15 years. The distribution of the peak area quotients of standard and target messenger-RNA (mRNA) as measured by laser-induced fluorescence capillary electrophoresis was closely correlated with the age of the samples. Further statistical analysis showed that bloodstains with age differences of 5 years and more exhibit statistical significant variances in peak area quotients of both housekeeping genes included in this study, beta-actin and cyclophilin. This can be of value when evidence from old cases is re-investigated. Our data show, that, although RNA continues to be degraded in dried bloodstains, mRNA suitable for RT-PCR can be isolated from samples stored for at least 15 years.
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Affiliation(s)
- Martin Bauer
- Institute of Legal Medicine, University of Wuerzburg, Versbacher Str. 3, Wuerzburg 97078, Germany.
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Maeno Y, Nakazawa S, Nagashima S, Sasaki J, Higo KM, Taniguchi K. Utility of the dried blood on filter paper as a source of cytokine mRNA for the analysis of immunoreactions in Plasmodium yoelii infection. Acta Trop 2003; 87:295-300. [PMID: 12826305 DOI: 10.1016/s0001-706x(03)00096-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We examined the utility of dried blood on filter paper for the source of cytokine messenger RNA (mRNA). Total RNA was isolated from the dried blood of mice infected with Plasmodium yoelii, and cDNA was amplified by reverse transcription-polymerase chain reaction (RT-PCR). As a reference, we extracted total RNA from peripheral blood collected at the same time as the preparation for dried blood. There was no difference in cytokine mRNA expression between the two sources; the dried blood on filter paper and the peripheral blood. Th1 cells, Th2 cells, and monocytes/macrophages derived cytokine mRNAs in the dried blood from infected mice were detected, and the increase of some of the cytokines mRNAs after infection was also observed. These results suggested that the dried blood on filter paper is satisfactory RNA source for immunological examination in field-based studies.
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Affiliation(s)
- Yoshimasa Maeno
- Department of Virology and Parasitology, Fujita Health University School of Medicine, 1-98 Kutsukate, Toyoake, Aichi 470-1192, Japan.
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McCabe LL, Therrell BL, McCabe ERB. Newborn screening: rationale for a comprehensive, fully integrated public health system. Mol Genet Metab 2002; 77:267-73. [PMID: 12468271 DOI: 10.1016/s1096-7192(02)00196-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Newborn screening has existed for approximately four decades. During that period of time, newborn screening has evolved conceptually from a laboratory test for a single disorder, phenylketonuria (PKU), to a multi-part public health system involving education, screening, diagnostic follow-up, treatment/management, and system evaluation. At a time when newborn screening is recognized as a model for predictive medicine, it also faces critical challenges that will determine its future credibility and viability. In order to understand these challenges, it is helpful to review briefly the history of newborn screening.
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Affiliation(s)
- Linda L McCabe
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1752, USA
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McCabe ER, McCabe LL. State-of-the-art for DNA technology in newborn screening. ACTA PAEDIATRICA (OSLO, NORWAY : 1992). SUPPLEMENT 1999; 88:58-60. [PMID: 10626581 DOI: 10.1111/j.1651-2227.1999.tb01160.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Just as metabolites, hormones and proteins are measured in newborn screening tests, DNA has become an analyte that is important in the screens for certain disorders. DNA confirmatory testing on the original dried blood specimen reduces the age at diagnostic confirmation and antibiotic prophylaxis initiation for neonates with sickle cell disease. Molecular genetic analysis of the initial specimens from newborns with elevated immunoreactive trypsinogen (IRT) for cystic fibrosis (CF) screening permits reduction of the IRT threshold value, improving specificity without compromising sensitivity. Because of this cost reduction, CF neonatal screening programs routinely incorporate DNA confirmatory testing into their initial CF screening algorithm. DNA analysis is also a valuable adjunct in screening programs for congenital adrenal hyperplasia (CAH), improving sensitivity and specificity. Incorporation of DNA into newborn screening programs will continue to be stimulated by development of robust, high throughput technologies for evaluation of this analyte. New paradigms for neonatal screening are evolving, including hearing screening in the newborn nursery. DNA testing, such as for mutations in the connexin 26 gene, may have a role in the evaluation of those screened positive. Newborn screening dried blood specimens are DNA databases. Therefore, there are significant ethical, legal and social issues that must be considered in the storage and utilization of neonatal screening specimens.
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Affiliation(s)
- E R McCabe
- Mattel Children's Hospital at UCLA, Los Angeles, CA, USA.
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22
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Detection of Epithelial Cells in Dried Blood Stains by Reverse Transcriptase-Polymerase Chain Reaction. J Forensic Sci 1999. [DOI: 10.1520/jfs14593j] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Gale KB, Ford AM, Repp R, Borkhardt A, Keller C, Eden OB, Greaves MF. Backtracking leukemia to birth: identification of clonotypic gene fusion sequences in neonatal blood spots. Proc Natl Acad Sci U S A 1997; 94:13950-4. [PMID: 9391133 PMCID: PMC28413 DOI: 10.1073/pnas.94.25.13950] [Citation(s) in RCA: 370] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/1997] [Accepted: 10/06/1997] [Indexed: 02/05/2023] Open
Abstract
Epidemiological evidence has suggested that some pediatric leukemias may be initiated in utero and, for some pairs of identical twins with concordant leukemia, this possibility has been strongly endorsed by molecular studies of clonality. Direct evidence for a prenatal origin can only be derived by prospective or retrospective detection of leukemia-specific molecular abnormalities in fetal or newborn samples. We report a PCR-based method that has been developed to scrutinize neonatal blood spots (Guthrie cards) for the presence of numerically infrequent leukemic cells at birth in individuals who subsequently developed leukemia. We demonstrate that unique or clonotypic MLL-AF4 genomic fusion sequences are present and detectable in neonatal blood spots from individuals who were diagnosed with acute lymphoblastic leukemia at ages 5 months to 2 years and, therefore, have arisen during fetal hematopoiesis in utero. This result provides unequivocal evidence for a prenatal initiation of acute leukemia in young patients. The method should be applicable to other fusion genes in children with common subtypes of leukemia and will be of value in attempts to unravel the natural history and etiology of this major subtype of pediatric cancer.
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Affiliation(s)
- K B Gale
- Leukaemia Research Fund Centre at the Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, United Kingdom
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25
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26
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Laird L, Dezateux C, Anionwu EN. Neonatal screening for sickle cell disorders: what about the carrier infants? BMJ (CLINICAL RESEARCH ED.) 1996; 313:407-11. [PMID: 8761233 PMCID: PMC2351830 DOI: 10.1136/bmj.313.7054.407] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- L Laird
- Department of Epidemiology and Biostatistics, Institute of Child Health, London
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27
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Jorgensen C, Sun R, Rossi JF, Costes J, Richard D, Bologna C, Sany J. Expression of a multidrug resistance gene in human rheumatoid synovium. Rheumatol Int 1995; 15:83-6. [PMID: 7481486 DOI: 10.1007/bf00262714] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The objective of this study was to assess the expression of a multidrug resistance (MDR) phenotype, implicated in the cellular resistance of tumor to chemotherapy, in rheumatoid synovial membrane. Synovial membrane from 16 rheumatoid (RA) patients was studied. Six patients with osteoarthritis constituted the control group. The cell membrane expression of the glycoprotein Pgp 170, encoded by the MDR 1 gene, was determined by an immunoperoxidase technique using two different monoclonal antibodies (JSB 1, C 219). The polymerase chain reaction (PCR) methods were used in parallel to detect the presence of the MDR 1 gene mRNA in the synovial cells. Pgp 170 was expressed on the cell membrane of five RA patients and MDR 1 cellular transcription was detected in one other RA patient. We did not observe any association between synovial glycoprotein expression and age, disease activity, and a specific treatment with a long-acting drug. However, MDR protein expression was associated with the successive treatment with more than three disease-modifying antirheumatic drugs (DMARDs). We concluded that the synovial membrane expresses a glycoprotein recognized by the antibodies JSB 1 and C 219. The absence of concomitant MDR 1 transcription suggests the expression of an atypical MDR phenotype in the synovial membrane, distinct from the Pgp 170 encoded by the MDR 1 gene. The implications of the MDR phenotype and the resistance of RA to DMARDs is further discussed.
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Affiliation(s)
- C Jorgensen
- Immuno-Rheumatology Department, Hopital Gui de Chauliac, Montpellier, France
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28
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Abstract
Molecular genetic techniques are being used increasingly in newborn screening programs. Initial applications involved genotypic confirmation of positive screening tests by DNA microextraction or direct amplification from the dried blood spots. More recently we have shown that RNA can be microextracted from newborn screening specimens, treated with reverse transcriptase and amplified by the polymerase chain reaction. Primary DNA screening is being considered for medium chain acyl-CoA dehydrogenase deficiency in an attempt to identify and treat affected children before their first hypoglycemic episodes. An exciting new development is the application of DNA "fingerprinting" to the microorganisms used in the bacterial inhibition assays for quality control of these critical biological reagents. Thus, molecular genetic approaches will be valuable, not only for confirmatory testing, but also for primary newborn screening for inborn errors of metabolism.
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Affiliation(s)
- E R McCabe
- Institute for Molecular Genetics, Baylor College of Medicine, Houston, TX 77030
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