We describe an 11 year old girl with a de novo unbalanced t(X;10) that resulted in a deletion of Xq26→Xqter and a trisomy of 10q21→10qter. Her clinical features were of distal trisomy 10q, but she lacked the cardiovascular and renal malformations observed in duplications of 10q24→10qter and had only moderate mental retardation. X inactivation was assessed on peripheral blood lymphocytes by late replication with BrdU (LR) and the human androgen receptor assay (HAR). By LR the der(X) was inactive without spreading to 10q21→10qter in all cells. The HAR assay showed skewed methylation of the paternal allele (90%). The correlation of HAR and LR suggests that the der(X) was paternally inherited and is consistent with data from other de novo balanced and unbalanced X;autosome translocations detected in females. This is the first report of parental origin of a de novo trisomy 10q.

Childhood acute leukemias are genetically complex disorders, with recurrent or random aberrations found in most patients. Their proper functional characterization is crucial for understanding the role they play in the process of leukemogenesis. We aimed to identify and characterize the genetic background of two leukemic entities. The transient myeloproliferative disorder (TMD) is a preleukemic condition that occurs in 10% of newborns with Down syndrome. Trisomy 21 together with in-utero gained mutations in the GATA1 gene are essential in TMD and represent an ideal "multi-hit" model to study leukemogenesis. We investigated an alternative pathogenic mechanism enabling TMD development in a confirmed absence of trisomy 21. Novel deletions in the GATA1 and JAK1 genes were described as potential drivers of this TMD. The deletion D65_C228 in GATA1 results in the expression of an aberrant isoform, which is predicted to lose transactivation potential and, more importantly, to partially lose the ability of recognizing physiological DNA binding sites, possibly triggering TMD alone. Our thorough characterization of JAK1 F636del questions its role in TMD development. Analysis of JAK/STAT signaling suggested decrease of kinase activity upon F636 loss. Cells harboring the aberrant JAK1 did not obtain cytokine-...

Background: For most patients with acute myeloid leukemia (AML) harboring a trisomy 8 an allogeneic hematopoietic stem cell transplantation (HSCT) is a suitable and recommended consolidation therapy. However, comparative outcome analyses between patients with and without trisomy 8 undergoing allogeneic HSCT have not been performed so far. Methods: We retrospectively analyzed clinical features, outcomes, and measurable residual disease (MRD) of 659 AML (12%, n = 81, with a trisomy 8) patients subjected to allogeneic HSCT as a consolidation therapy. Results: The presence of a trisomy 8 associated with a trend for higher age at diagnosis, AML of secondary origin, lower white blood cell counts at diagnosis, worse ELN2017 genetic risk, wild-type NPM1, and mutated IDH1/2 and JAK2. Outcomes after allogeneic HSCT in the entire cohort did not differ between patients with a sole trisomy 8, trisomy 8 with additional cytogenetic aberrations or without a trisomy 8. A trisomy 8 did not affect outcomes within the three ELN2017 risk groups. In accordance with findings in unselected patient cohorts, persistent MRD at allogeneic HSCT in patients with a trisomy 8 identified individuals with a higher risk of relapse following allogeneic HSCT. Conclusions: Outcomes of trisomy 8 patients after allogeneic HSCT did not compare unfavorably to that of other AML patients following allogeneic HSCT. Rather than the presence or absence of a trisomy 8, additional genetic aberrations and MRD at HSCT define outcome differences and aid in informed treatment decisions.

No description available.

Hematopoiesis is the highly regenerative process of producing billions of blood cells each day, including white blood cells, red blood cells, and platelets. Given the relatively short life span of these mature cells, hematopoiesis is dependent on stem and progenitor cells to generate renewed progeny, which represents a tightly regulated process. This includes cell intrinsic and external factors, and where dysregulation can lead to anemia and cancer. As such, the hematopoietic hierarchy has been intensely studied for nearly a century and represents a gold standard model of cell fate and developmental biology, in research and clinical applications. Cellular models, such as in vitro culture and human-mouse xenografts in vivo, have been developed to explain complex phenomena pertaining to hematopoiesis and also interrogate processes which are too invasive to study in humans. Hematopoietic generation is required beyond sustaining homeostasis, and progenitors can be damaged through cytotoxic injuries such as radiation and standard chemotherapy, and also undergo leukemic transformation. There are two main treatment modalities for leukemia patients (a) receiving a stem cell transplant, and (b) drug or radiation-based therapy. In the former, shortages of donors and stem cells has remained an unmet clinical need for decades. In the latter, selective targeting of genetic mutations has become a successful standard-of-care in leukemias such as chronic myelogenous leukemia and acute promyelocytic leukemia. However, in the most common adult hematologic malignancy, chronic lymphocytic leukemia (CLL), similar targeting therapies have not been developed. Altogether, shortages of stem cells from healthy donors, chemotherapy-induced immune dysfunction, and a lack of targeted therapies, all reinforce the immediate need for innovative cellular models to address these clinical problems. To generate additional sources of human hematopoietic progenitors for laboratory study, human PSCs have been used. Unlike hematopoietic progenitor cells collected from healthy and leukemic donors, human pluripotent stem cells (PSC) can be easily propagated and expanded in vitro. PSCs can generate hematopoietic progenitor cells, but they remain poorly understood and have not been robustly applied to solve the aforementioned deficiencies related to patient treatment. Importantly, the biological regulation of both hematopoiesis and PSCs has been experimentally confirmed to significantly deviate between humans and other animals, such as mice, further reinforcing the importance of human-specific cell models of hematopoiesis. Therefore, I hypothesized that human stem cell models provide a focused approach to interrogate the regulation of hematopoiesis from the apex of the hierarchy, which can be used to understand the promotion of healthy hematopoiesis and understand malignant transformation. Collectively, the data presented within this thesis offer a deeper conceptualization of human stem cell models and the deconvolution of several complex components of hematopoietic regulation. This work has revealed novel, clinically relevant, and actionable targets to ultimately enable the promotion of healthy hematopoiesis on multiple fronts. / Thesis / Doctor of Philosophy (PhD) / This thesis presents research on novel molecular and genetic regulatory pathways of self-renewal and differentiation in models of healthy and malignant human hematopoiesis. The origin of healthy hematopoietic regulation stems from a large body of work spanning decades and encompasses many efforts by others to derive hematopoietic stem cells from human pluripotent cells. The development of a genetic model for the malignant regulation of CLL was truly serendipitous, was propelled through robust and intriguing results that begged for further exploration, and filled a clinical gap in identifying actionable targets in CLL. Lastly, these two projects, along with my supportive roles in other published works throughout my graduate studies, instructed me to develop a human-mouse transplant model to uncover the biology of regenerating healthy hematopoiesis during injury.

Chen, Zhang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (p. 109-114). / Abstracts in English and Chinese. / ABSTRACT --- p.I / 摘要 --- p.III / ACKNOWLEDGEMENTS --- p.IV / PUBLICATIONS --- p.VI / CONTRIBUTORS --- p.VII / TABLE OF CONTENTS --- p.VIII / LIST OF TABLES --- p.XIII / LIST OF FIGURES --- p.XIV / LIST OF ABBREVIATIONS --- p.XVI / Chapter SECTION I : --- BACKGROUND --- p.1 / Chapter CHAPTER 1: --- PRENATAL DIAGNOSIS OF FETAL TRISOMY BY NEXT GENERATION SEQUENCING TECHNOLOGY --- p.2 / Chapter 1.1 --- FETAL TRISOMY --- p.2 / Chapter 1.2 --- CONVENTIONAL PRENATAL DIAGNOSIS OF FETAL TRISOMIES --- p.3 / Chapter 1.3 --- CELL FREE FETAL D N A AND ITS APPLICATION IN PRENATAL DIAGNOSIS --- p.5 / Chapter 1.4 --- NEXT GENERATION SEQUENCING TECHNOLOGY --- p.5 / Chapter 1.5 --- SUBSTANTIAL BIAS IN THE NEXT GENERATION SEQUENCING PLATFORM --- p.9 / Chapter 1.6 --- PRENATAL DIAGNOSIS OF TRISOMY BY NEXT GENERATION SEQUENCING --- p.10 / Chapter 1.7 --- AIMS OF THIS THESIS --- p.11 / Chapter SECTION I I : --- MATERIALS AND METHODS --- p.13 / Chapter CHAPTER 2: --- METHODS FOR NONINVASIVE PRENATAL DIAGNOSIS OF FETAL TRISOMY MATERNAL PLASMA DNA SEQUENCING --- p.14 / Chapter 2.1 --- STUDY DESIGN AND PARTICIPANTS --- p.14 / Chapter 2.1.1 --- Ethics Statement --- p.14 / Chapter 2.1.2 --- "Study design, setting and participants" --- p.14 / Chapter 2.2 --- MATERNAL PLASMA D N A SEQUENCING --- p.17 / Chapter 2.3 --- SEQUENCING DATA ANALYSIS --- p.18 / Chapter SECTION I I I : --- TRISOMY 13 AND 18 DETECTION BY THE T21 BIOINFORMATICS ANALYSIS PIPELINE --- p.21 / Chapter CHAPTER 3: --- THE T21 BIOINFORMATICS ANALYSIS PIPELINE FOR TRISOMY 13 AND 18 DETECTION --- p.22 / Chapter 3.1 --- INTRODUCTION --- p.22 / Chapter 3.2 --- METHODS --- p.23 / Chapter 3.2.1 --- Bioinformatics analysis pipeline for trisomy 13 and 18 detection --- p.23 / Chapter 3.3 --- RESULTS --- p.23 / Chapter 3.3.1 --- Performance of the T21 bioinformatics analysis pipeline for trisomy 13 and 18 detection --- p.23 / Chapter 3.3.2 --- The precision of quantifying chrl 3 and chrl 8 --- p.27 / Chapter 3.4 --- DISCUSSION --- p.29 / Chapter SECTION IV : --- IMPROVING THE T21 BIOINFORMATICS ANALYSIS PIPELINE FOR TRISOMY 13 AND 18 DETECTION --- p.30 / Chapter CHAPTER 4: --- IMPROVING THE ALIGNMENT --- p.31 / Chapter 4.1 --- INTRODUCTION --- p.31 / Chapter 4.2 --- METHODS --- p.32 / Chapter 4.2.1 --- Allowing mismatches in the index sequences --- p.32 / Chapter 4.2.2 --- Calculating the mappability of the human reference genome --- p.33 / Chapter 4.2.3 --- Aligning reads to the non-repeat masked human reference genome --- p.34 / Chapter 4.2.4 --- Trisomy 13 and 18 detection --- p.34 / Chapter 4.3 --- RESULTS --- p.34 / Chapter 4.3.1 --- Increasing read numbers by allowing mismatches in the index sequences --- p.34 / Chapter 4.3.2 --- Increasing read numbers by using the non-masked reference genome for alignment . --- p.38 / Chapter 4.3.3 --- Allowing mismatches in the read alignment --- p.42 / Chapter 4.3.4 --- The performance of trisomy 13 and 18 detection after improving the alignment --- p.47 / Chapter 4.4 --- DISCUSSION --- p.50 / Chapter CHAPTER 5: --- REDUCING THE GC BIAS BY CORRECTION OF READ COUNTS --- p.53 / Chapter 5.1 --- INTRODUCTION --- p.53 / Chapter 5.2 --- METHODS --- p.54 / Chapter 5.2.1 --- Read alignment --- p.54 / Chapter 5.2.2 --- Calculating the correlation between GC content and read counts --- p.55 / Chapter 5.2.3 --- GC correction in read counts --- p.55 / Chapter 5.2.4 --- Trisomy 13 and 18 detection --- p.56 / Chapter 5.3 --- RESULTS --- p.56 / Chapter 5.3.1 --- GC bias in plasma DNA sequencing --- p.56 / Chapter 5.3.2 --- Correcting the GC bias in read counts by linear regression --- p.59 / Chapter 5.3.3 --- Correcting the GC bias in read counts by LOESS regression --- p.65 / Chapter 5.3.4 --- Bin size --- p.72 / Chapter 5.4 --- DISCUSSION --- p.75 / Chapter CHAPTER 6: --- REDUCING THE GC BIAS BY MODIFYING THE GENOMIC REPRESENTATION CALCULATION --- p.77 / Chapter 6.1 --- INTRODUCTION --- p.77 / Chapter 6.2 --- METHODS --- p.78 / Chapter 6.2.1 --- Modifying the genomic representation calculation --- p.78 / Chapter 6.2.2 --- Trisomy 13 and 18 detection --- p.78 / Chapter 6.2.3 --- Combining GC correction and modified genomic representation --- p.78 / Chapter 6.3 --- RESULTS --- p.79 / Chapter 6.3.1 --- Reducing the GC bias by modifying genomic representation calculation --- p.79 / Chapter 6.3.2 --- Combining GC correction and modified genomic representation --- p.86 / Chapter 6.4 --- DISCUSSION --- p.89 / Chapter CHAPTER 7: --- IMPROVING THE STATISTICS FOR TRISOMY 13 AND 18 DETECTION --- p.91 / Chapter 7.1 --- INTRODUCTION --- p.91 / Chapter 7.2 --- METHODS --- p.92 / Chapter 7.2.1 --- Comparing chrl 3 or chrl8 with other chromosomes within the sample --- p.92 / Chapter 7.2.2 --- Comparing chrl 3 or chrl 8 with the artificial chromosomes --- p.92 / Chapter 7.3 --- RESULTS --- p.93 / Chapter 7.3.1 --- Determining the trisomy 13 and 18 status by comparing chromosomes within the samples --- p.93 / Chapter 7.3.2 --- Determining the trisomy 13 and 18 status by comparing chrl3 or chrl 8 with artificial chromosomes --- p.97 / Chapter 7.4 --- DISCUSSION --- p.100 / Chapter SECTION V : --- CONCLUDING REMARKS --- p.102 / Chapter CHAPTER 8: --- CONCLUSION AND FUTURE PERSPECTIVES --- p.103 / Chapter 8.1 --- THE PERFORMANCE OF THE T21 BIOINFORMATICS ANALYSIS PIPELINE DEVELOPED FOR TRISOMY 21 DETECTION IS SUBOPTIMAL FOR TRISOMY 13 AND 18 DETECTION --- p.103 / Chapter 8.2 --- THE ALIGNMENT COULD BE IMPROVED BY ALLOWING ONE MISMATCH IN THE INDEX AND USING THE NON-REPEAT MASKED HUMAN REFERENCE GENOME AS THE ALIGNMENT REFERENCE --- p.104 / Chapter 8.3 --- THE PRECISION OF QUANTIFYING CHR13 AND CHR18 COULD BE IMPROVED BY THE G C CORRECTION OR THE MODIFIED GENOMIC REPRESENTATION --- p.104 / Chapter 8.4 --- THE STATISTICS FOR TRISOMY 13 AND 18 DETECTION COULD BE IMPROVED BY COMPARING CHR13 OR CHR18 WITH ARTIFICIAL CHROMOSOMES WITHIN THE SAMPLE --- p.105 / Chapter 8.5 --- PROSPECTS FOR FUTURE WORK --- p.106 / REFERENCE --- p.109

The primary aim of this study was to determine the effectiveness of array-based technology for detecting and quantifying the presence of mosaicism. This aim was achieved by studying individuals having mosaicism for Down syndrome. SNP arrays were performed on 13 samples from individuals with mosaicism for trisomy 21, 13 samples from individuals with normal chromosome 21complements (negative controls) and 5 samples from individuals with full or partial trisomy 21 (positive controls). In addition, BAC arrays were processed on 6 samples from individuals with mosaicism for trisomy 21, 3 negative controls and 1 positive control. These studies have shown that array-based technology is effective for detecting mosaicism that is present in 20% or more cells with the results being consistent for both platforms. We also demonstrated the strength of array-based technology to identify previously unrecognized chromosomal mosaicism. A second aim of this study was to gain insight regarding the effect that trisomy 21 has on telomere attrition and the frequency of chromosomal instability. This study provides the first reported measure of both chromosome-specific telomere lengths and the frequency of acquired chromosome abnormalities in trisomic cells and isogenic euploid cells obtained from the same individuals. A chromosome-specific telomere length assay was performed on lymphocytes obtained from 24 young individuals with mosaicism for Down syndrome. While differences in overall telomere signal intensities were observed between the euploid and trisomic cells within a person, strikingly similar profiles for chromosome-specific telomere intensities were observed between the cell types within a person. Analyses were also completed on lymphoblast samples obtained from 8 older individuals with mosaicism for Down syndrome, including 5 individuals without dementia and 3 individuals with dementia. In the older study subjects, a significant inverse correlation was observed between telomere length and the frequency of micronuclei, suggesting that telomeric shortening is leading to an increased frequency of chromosomal instability, possibly through dicentric chromosome formation. However, further studies of more individuals, especially additional analyses of older individuals, are needed. These future studies may help to identify genomic regions of interest and serve to inform investigators of potential candidate genes in the etiology of dementia.

Gliomas are brain tumors arising from neuroglia. In most cases astrocytic or oligodendroglial component is the main element of the tumor. Non-random chromosomal abberations are found in tumor cells as was revealed previously. The aim of this study was a fluorescence in-situ hybridisation analysis (FISH) of tissue samples obtained during neurosurgical procedures, determine the frequence of selected chromosomal abberations, further correlation with morphological and clinical data and statistical analysis of the results. During six years 264 tissue samples were gained in which FISH with defined probes was performed. The acquired results were compared with histological analysis and selected clinical data (age, Karnofsky score, extent of resection, overall survival). The whole series was divided into 7 groups by tumor type for further statistical analysis. In every group median and mean survival time was calculated, Kaplan-Meier analysis was focused on influence of selected parameters to overall survival. In some categories Cox regression model was created to achieve a hazard ratio of selected parameters. In WHO Grade II and III tumors the risk of malignant progression and tumor upgrading is significantly higher in comparison with samples where specific abberations were not found (EGFR amplification, CDKN2A and...

La Trisomie 21 ou Syndrome de Down, est due à la présence surnuméraire du chromosome 21 humain (Hsa21), le surdosage génétique qui en résulte provoque différents phénotypes. Cette pathologie est la première cause de retard mental. Notre étude vise à savoir si l’aneuploïdie d’un intervalle génétique, encore non étudié, entraîne des modifications dans la mise en place des processus à l’origine des facultés cognitives. Cet intervalle, entre les gènes Cstb et Prmt2 est porté par le chromosome murin 10 (MMU10) au sein d’une portion homologue à la partie télomérique du Hsa21. Pour cela de nouveaux modèles murins ont été créés, Ms4Yah est monosomique et Ts3Yah est trisomique pour cet intervalle. Le but est donc de caractériser les conséquences de l’aneuploïdie sur le fonctionnement des neurones permettant l’encodage des informations, appelé plasticité synaptique à long terme. Nous avons enregistré ce phénomène au niveau de la communication entre le cortex et le striatum, structures impliquées dans les processus mnémoniques, grâce à la technique électrophysiologique de patch clamp en configuration cellule entière. Ces enregistrements sont faits in vitro sur tranches de cerveaux de souris. Les propriétés électrophysiologiques des NETMs ont été caractérisées. La plasticité synaptique corticostriatale à long terme de type glutamatergique a été étudiée avec des protocoles de stimulation spécifiques, appliqués au niveau cortical. Des protocoles de conditionnement à haute et à basse fréquence ont été utilisés. Nous avons observé que l’aneuploïdie portée par les modèles avait une influence sur la mise en place de la plasticité synaptique corticostriatale à long terme qui est différente en fonction du dosage génétique. Ms4Yah met en place une DLT suite au protocole SHF de même que Ts3Yah. Lorsque le protocole SBF est utilisé Ms4Yah met en place une forme de plasticité à court terme contrairement à Ts3Yah qui présente une DLT. L’intervalle étudié ici jouerait donc un rôle dans le phénotype de la Trisomie 21. Certains gènes de l’intervalle semblent être de bons candidats pour expliquer les phénomènes observés, notamment S100b, Pcbp3 et Trmp2. / Trisomy 21 or Down syndrome is due to a third copy of human chromosome 21 (Hsa21) in the genome, this leads to a global genetic overexpression which results on multiple behavioral phenotypes. This pathology is the first and most common cause of mental retardation. Our study aims to understand whether an aneuploidy of a non-studied genetic interval, included in Hsa21, causes changes in processes mediating intellectual abilities. This interval, between Ctsb and Prmt2, is located on murine chromosome 10 (MMU10) within an homologous portion of the Hsa21 telomeric part. Thus, new mouse models have been engineered, Ms4Yah is monosomic and Ts3Yah trisomic for Cstb-Prmt2 interval. Hence, the aim of this project is to characterized aneuploidy consequences on neuronal functions which lead to information encoding, named long term synaptic plasticity. We have recorded this phenomenon within cortex-striatum neuronal connexion, which is involved in mnemonic processes, using whole-cell patch-clamp electrophysiological technique. Records were made in vitro on mouse horizontal brain slice. We characterized METMs electrophysiological properties. Then, glutamatergic corticostriatal long term synaptic plasticity was studied with specific stimulation protocols applied on the cortex. High and low frequency conditioning protocols were used. We observed that aneuploidy of the models influenced corticostriatal long term synaptic plasticity setting which is different according to the genetic dosage. Ms4Yah showed LTD after HFS protocol like Ts3Yah. But when SBF was applied, Ms4Yah shows a short term plasticity form, conversely Ts3Yah shows anew a LTD. The studied interval may play here a role in phenotype of Trisomy 21. Some of the genes comprised in the Ctsb-Prmt2 interval seemed to be good candidates to explain observed phenotypes, namely S100b, Pcbp3 and Trmp2.

Gliomas are brain tumors arising from neuroglia. In most cases astrocytic or oligodendroglial component is the main element of the tumor. Non-random chromosomal abberations are found in tumor cells as was revealed previously. The aim of this study was a fluorescence in-situ hybridisation analysis (FISH) of tissue samples obtained during neurosurgical procedures, determine the frequence of selected chromosomal abberations, further correlation with morphological and clinical data and statistical analysis of the results. During six years 264 tissue samples were gained in which FISH with defined probes was performed. The acquired results were compared with histological analysis and selected clinical data (age, Karnofsky score, extent of resection, overall survival). The whole series was divided into 7 groups by tumor type for further statistical analysis. In every group median and mean survival time was calculated, Kaplan-Meier analysis was focused on influence of selected parameters to overall survival. In some categories Cox regression model was created to achieve a hazard ratio of selected parameters. In WHO Grade II and III tumors the risk of malignant progression and tumor upgrading is significantly higher in comparison with samples where specific abberations were not found (EGFR amplification, CDKN2A and...