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The genetic basis of human uniqueness remains one of the most enduring mysteries in biological anthropology. The goal of this research project was to identify, characterize, and infer the origin and function of novel elements in the human genome that are not functionally shared with other apes. Our approach toward this goal was to utilize a variety of genome alignment tools to discover islands of non‐conserved DNA sequences, followed by theoretical and computational analysis of those regions using synteny sequence analysis. We discovered families of microRNA genes on human chromosome 21 with no detectable orthologs in the other African apes. We then developed a working model of their origin through repeated rounds of segmental duplication occurring within an array of rRNA genes. Target prediction reveals potential roles for these microRNA genes in the embryonic development of the central nervous system. We conclude that the 21p11 region of human chromosome 21 has undergone segmental duplication events that generated de novo microRNA genes from within a field of rRNA genes. These microRNA genes may have played a role in the unique evolutionary trajectory of the human lineage through their modulation of genes involved in embryonic development. [ABSTRACT FROM AUTHOR]

Abstract Background Trisomy 21 (T21) is a genetic alteration characterised by the presence of an extra full or partial human chromosome 21 (Hsa21) leading to Down syndrome (DS), the most common form of intellectual disability (ID). It is broadly agreed that the presence of extra genetic material in T21 gives origin to an altered expression of genes located on Hsa21 leading to DS phenotype. The aim of this study was to analyse T21 and normal control blood cell gene expression profiles obtained by total RNA sequencing (RNA-Seq). Results The results were elaborated by the TRAM (Transcriptome Mapper) software which generated a differential transcriptome map between human T21 and normal control blood cells providing the gene expression ratios for 17,867 loci. The obtained gene expression profiles were validated through real-time reverse transcription polymerase chain reaction (RT-PCR) assay and compared with previously published data. A post-analysis through transcriptome mapping allowed the identification of the segmental (regional) variation of the expression level across the whole genome (segment-based analysis of expression). Interestingly, the most over-expressed genes encode for interferon-induced proteins, two of them (MX1 and MX2 genes) mapping on Hsa21 (21q22.3). The altered expression of genes involved in mitochondrial translation and energy production also emerged, followed by the altered expression of genes encoding for the folate cycle enzyme, GART, and the folate transporter, SLC19A1. Conclusions The alteration of these pathways might be linked and involved in the manifestation of ID in DS.

Background: Trisomy 21 (T21) is a genetic alteration characterised by the presence of an extra full or partial human chromosome 21 (Hsa21) leading to Down syndrome (DS), the most common form of intellectual disability (ID). It is broadly agreed that the presence of extra genetic material in T21 gives origin to an altered expression of genes located on Hsa21 leading to DS phenotype. The aim of this study was to analyse T21 and normal control blood cell gene expression profiles obtained by total RNA sequencing (RNA-Seq). Results: The results were elaborated by the TRAM (Transcriptome Mapper) software which generated a differential transcriptome map between human T21 and normal control blood cells providing the gene expression ratios for 17,867 loci. The obtained gene expression profiles were validated through real-time reverse transcription polymerase chain reaction (RT-PCR) assay and compared with previously published data. A post-analysis through transcriptome mapping allowed the identification of the segmental (regional) variation of the expression level across the whole genome (segment-based analysis of expression). Interestingly, the most over-expressed genes encode for interferon-induced proteins, two of them (MX1 and MX2 genes) mapping on Hsa21 (21q22.3). The altered expression of genes involved in mitochondrial translation and energy production also emerged, followed by the altered expression of genes encoding for the folate cycle enzyme, GART, and the folate transporter, SLC19A1. Conclusions: The alteration of these pathways might be linked and involved in the manifestation of ID in DS. [ABSTRACT FROM AUTHOR]

Adults with Down syndrome (DS), an undifferentiated developmental delay (UnD) and no developmental delay practiced a manual target aiming task either with or without on-line visual feedback. Following acquisition, participants performed a retention test involving the same sensory condition available during practice, followed by a transfer test under the other sensory condition. Although the participants with UnD were highly dependent on visual feedback for movement accuracy, participants with DS relied more on either kinesthetic feedback or feedforward control for spatial precision. Participants in all three groups improved their movement times with practice. This improvement was associated both with an increase in peak velocity and a reduction in the time required to decelerate their aiming movements. Contrary to our expectations, improvements in performance were not specific to the sensory conditions available during practice. [ABSTRACT FROM AUTHOR]

Abstract Background The thyroid is the earliest endocrine structure to appear during human development, and thyroid hormones are necessary for proper organism development, in particular for the nervous system and heart, normal growth and skeletal maturation. To date a quantitative, validated transcriptional atlas of the whole normal human thyroid does not exist and the availability of a detailed expression map might be an excellent occasion to investigate the many features of the thyroid transcriptome. Results We present a view at the molecular level of the normal human thyroid histology and physiology obtained by a systematic meta-analysis of all the available gene expression profiles for the whole organ. A quantitative transcriptome reference map was generated by using the TRAM (Transcriptome Mapper) software able to combine, normalize and integrate a total of 35 suitable datasets from different sources thus providing a typical reference expression value for each of the 27,275 known, mapped transcripts obtained. The experimental in vitro validation of data was performed by “Real-Time” reverse transcription polymerase chain reaction showing an excellent correlation coefficient (r = 0.93) with data obtained in silico. Conclusions Our study provides a quantitative global reference portrait of gene expression in the normal human thyroid and highlights differential expression between normal human thyroid and a pool of non-thyroid tissues useful for modeling correlations between thyroidal gene expression and specific thyroid functions and diseases. The experimental in vitro validation supports the possible usefulness of the human thyroid transcriptome map as a reference for molecular studies of the physiology and pathology of this organ.

Abstract Background Down syndrome (DS) is characterized by the presence of an extra full or partial human chromosome 21 (Hsa21). An invaluable model to define genotype‐phenotype correlations in DS is the study of the extremely rare cases of partial (segmental) trisomy 21 (PT21), the duplication of only a delimited region of Hsa21 associated or not to DS. A systematic retrospective reanalysis of 125 PT21 cases described up to 2015 allowed the creation of the most comprehensive PT21 map and the identification of a 34‐kb highly restricted DS critical region (HR‐DSCR) as the minimal region whose duplication is shared by all PT21 subjects diagnosed with DS. We reanalyzed at higher resolution three cases previously published and we accurately searched for any new PT21 reports in order to verify whether HR‐DSCR limits could prospectively be confirmed and possibly refined. Methods Hsa21 partial duplications of three PT21 subjects were refined by adding array‐based comparative genomic hybridization data. Seven newly described PT21 cases fulfilling stringent cytogenetic and clinical criteria have been incorporated into the PT21 integrated map. Results The PT21 map now integrates fine structure of Hsa21 sequence intervals of 132 subjects onto a common framework fully consistent with the presence of a duplicated HR‐DSCR, on distal 21q22.13 sub‐band, only in DS subjects and not in non‐DS individuals. No documented exception to the HR‐DSCR model was found. Conclusions The findings presented here further support the association of the HR‐DSCR with the diagnosis of DS, representing an unbiased validation of the original model. Further studies are needed to identify and characterize genetic determinants presumably located in the HR‐DSCR and functionally associated to the critical manifestations of DS.

This study explored parental experiences and factors impacting on the successful transitioning of young people with Down syndrome from primary to mainstream secondary school settings in Ireland. This qualitative study used semi‐structured interviews to examine the perspectives of parents (N = 5) and secondary school teachers (N = 3) regarding this transition process. Interviews were analysed via thematic analysis using a social constructionist perspective. Results revealed that open communication between parents and schools was a significant factor impacting positively on the experience. However, results also indicated that a balancing act was required to manage factors such as parental fears and expectations, educational resources and the challenges in supporting the child to navigate the social world of mainstream schools. Findings identify challenges to the successful inclusion of young people with Down syndrome at secondary‐school level. Recommendations are made for future research. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) is due to the presence of an extra full or partial chromosome 21 (Hsa21). The identification of genes contributing to DS pathogenesis could be the key to any rational therapy of the associated intellectual disability. We aim at generating quantitative transcriptome maps in DS integrating all gene expression profile datasets available for any cell type or tissue, to obtain a complete model of the transcriptome in terms of both expression values for each gene and segmental trend of gene expression along each chromosome. We used the TRAM (Transcriptome Mapper) software for this meta-analysis, comparing transcript expression levels and profiles between DS and normal brain, lymphoblastoid cell lines, blood cells, fibroblasts, thymus and induced pluripotent stem cells, respectively. TRAM combined, normalized, and integrated datasets from different sources and across diverse experimental platforms. The main output was a linear expression value that may be used as a reference for each of up to 37,181 mapped transcripts analyzed, related to both known genes and expression sequence tag (EST) clusters. An independent example in vitro validation of fibroblast transcriptome map data was performed through “Real-Time” reverse transcription polymerase chain reaction showing an excellent correlation coefficient (r = 0.93, p < 0.0001) with data obtained in silico. The availability of linear expression values for each gene allowed the testing of the gene dosage hypothesis of the expected 3:2 DS/normal ratio for Hsa21 as well as other human genes in DS, in addition to listing genes differentially expressed with statistical significance. Although a fraction of Hsa21 genes escapes dosage effects, Hsa21 genes are selectively over-expressed in DS samples compared to genes from other chromosomes, reflecting a decisive role in the pathogenesis of the syndrome. Finally, the analysis of chromosomal segments reveals a high prevalence of Hsa21 over-expressed segments over the other genomic regions, suggesting, in particular, a specific region on Hsa21 that appears to be frequently over-expressed (21q22). Our complete datasets are released as a new framework to investigate transcription in DS for individual genes as well as chromosomal segments in different cell types and tissues.

Background: Down syndrome (DS) is a genetic disorder caused by presence of extra copy of human chromosome 21. It is characterised by several clinical phenotypes. Motor dysfunction due to hypotonia is commonly seen in individuals with DS and its etiology is yet unknown. Ts1Cje, which has a partial trisomy (Mmu16) homologous to Hsa21, is well reported to exhibit various typical neuropathological features seen in individuals with DS. This study investigated the role of skeletal muscles and peripheral nerve defects in contributing to muscle weakness in Ts1Cje mice. Results: Assessment of the motor performance showed that, the forelimb grip strength was significantly (P<0.0001) greater in the WT mice compared to Ts1Cje mice regardless of gender. The average survival time of the WT mice during the hanging wire test was significantly (P<0.0001) greater compared to the Ts1Cje mice. Also, the WT mice performed significantly (P<0.05) better than the Ts1Cje mice in the latency to maintain a coordinated motor movement against the rotating rod. Adult Ts1Cje mice exhibited significantly (P<0.001) lower nerve conduction velocity compared with their aged matched WT mice. Further analysis showed a significantly (P<0.001) higher population of type I fibres in WT compared to Ts1Cje mice. Also, there was significantly (P<0.01) higher population of COX deficient fibres in Ts1Cje mice. Expression of Myf5 was significantly (P<0.05) reduced in triceps of Ts1Cje mice while MyoD expression was significantly (P<0.05) increased in quadriceps of Ts1Cje mice. Conclusion: Ts1Cje mice exhibited weaker muscle strength. The lower population of the type I fibres and higher population of COX deficient fibres in Ts1Cje mice may contribute to the muscle weakness seen in this mouse model for DS. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) is due to the presence of an extra full or partial chromosome 21 (Hsa21). The identification of genes contributing to DS pathogenesis could be the key to any rational therapy of the associated intellectual disability. We aim at generating quantitative transcriptome maps in DS integrating all gene expression profile datasets available for any cell type or tissue, to obtain a complete model of the transcriptome in terms of both expression values for each gene and segmental trend of gene expression along each chromosome. We used the TRAM (Transcriptome Mapper) software for this meta-analysis, comparing transcript expression levels and profiles between DS and normal brain, lymphoblastoid cell lines, blood cells, fibroblasts, thymus and induced pluripotent stem cells, respectively. TRAM combined, normalized, and integrated datasets from different sources and across diverse experimental platforms. The main output was a linear expression value that may be used as a reference for each of up to 37,181 mapped transcripts analyzed, related to both known genes and expression sequence tag (EST) clusters. An independent example in vitro validation of fibroblast transcriptome map data was performed through "Real-Time" reverse transcription polymerase chain reaction showing an excellent correlation coefficient (r = 0.93, p < 0.0001) with data obtained in silico. The availability of linear expression values for each gene allowed the testing of the gene dosage hypothesis of the expected 3:2 DS/normal ratio for Hsa21 as well as other human genes in DS, in addition to listing genes differentially expressed with statistical significance. Although a fraction of Hsa21 genes escapes dosage effects, Hsa21 genes are selectively over-expressed in DS samples compared to genes from other chromosomes, reflecting a decisive role in the pathogenesis of the syndrome. Finally, the analysis of chromosomal segments reveals a high prevalence of Hsa21 over-expressed segments over the other genomic regions, suggesting, in particular, a specific region on Hsa21 that appears to be frequently over-expressed (21q22). Our complete datasets are released as a new framework to investigate transcription in DS for individual genes as well as chromosomal segments in different cell types and tissues. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) results from the triplication of genes located on human chromosome 21 (Hsa21). Though many cognitive and behavioral impairments are associated with DS, sleep disturbances remain poorly understood despite being a reported phenotype in approximately 60% of individuals diagnosed with DS. In this study, sleep and electroencephalography (EEG) oscillations were recorded from aged (12–14 mos.) Dp(16)1Yey/+ mice (Dp16), a mouse model of DS. We observed disrupted sleep demonstrated by increased activity during the dark phase and increased time awake at the expense of NREM sleep compared to wild-type mice. In addition, we found that Dp16 mice display significant differences in relative EEG power distribution among oscillation frequencies in both sleep and awake states. These results in Dp16 mice are consistent with sleep disturbances found in individuals with DS, and the abnormal EEG oscillations in aged Dp16 mice suggest a potential role for GABAergic activity in these sleep and EEG abnormalities. These sleep and EEG data reflect underlying differences in neuronal activity at the network level and thus are causative agents rather than merely symptoms of DS. [ABSTRACT FROM AUTHOR]

Summary: The regulator of calcineurin 1 (RCAN1) was first discovered as a gene located on human chromosome 21, expressed in neurons and overexpressed in the brains of Down syndrome individuals. Increased expression of RCAN1 has been linked with not only Down syndrome‐associated pathology but also an associated neurological disorder, Alzheimer's Disease, in which neuronal RCAN1 expression is also increased. RCAN1 has additionally been demonstrated to affect other cell types including endocrine cells, with links to the pathogenesis of β‐cell dysfunction in type 2 diabetes. The primary functions of RCAN1 relate to the inhibition of the phosphatase calcineurin, and to the regulation of mitochondrial function. Various forms of cellular stress such as reactive oxygen species and hyperglycaemia cause transient increases in RCAN1 expression. The short term (hours to days) induction of RCAN1 expression is generally thought to have a protective effect by regulating the expression of pro‐survival genes in multiple cell types, many of which are mediated via the calcineurin/NFAT transcriptional pathway. However, strong evidence also supports the notion that chronic (weeks‐years) overexpression of RCAN1 has a detrimental effect on cells and that this may drive pathophysiological changes in neurons and endocrine cells linked to Down syndrome, Alzheimer's Disease and type 2 diabetes. Here we review the evidence related to these roles of RCAN1 in neurons and endocrine cells and their relationship to these human health disorders. [ABSTRACT FROM AUTHOR]

Aims: Down syndrome (DS) is a common cause of mental retardation accompanied by cognitive impairment. Comprehensive studies suggested a link between development and ageing, as nearly all individuals with DS develop Alzheimer disease (AD)‐like pathology. However, there is still a paucity of data on tau in early DS to support this notion. Methods: Using morphometric immunohistochemistry we compared tau phosphorylation in normal brains and in brains of individuals with DS from early development until early postnatal life. Results: We observed in DS a critical loss of physiological phosphorylation of tau. Rhombencephalic structures showed prominent differences between controls and DS using antibodies AT8 (Ser‐202/Thr‐205) and AT180 (Thr‐231). In contrast, in the subiculum only a small portion of controls deviated from DS using antibodies AT100 (Thr‐212/Ser‐214) and AT270 (Thr‐181). With exception of the subiculum, phosphorylation‐independent tau did not differ between groups, as confirmed by immunostaining for the HT‐7 antibody (epitope between 159 and 163 of the human tau) as well. Discussion: Our observations suggest functional tau disturbance in DS brains during development, rather than axonal loss. This supports the role of tau as a further important player in the pathophysiology of cognitive impairment in DS and related AD. [ABSTRACT FROM AUTHOR]

Down syndrome (DS), trisomy of human chromosome 21 (Hsa21), is the most common genetic cause of intellectual disability (ID). There are no treatments for the cognitive deficits. The Ts65Dn is a partial trisomy mouse model of DS that shows learning and memory (LM) impairments and other abnormalities relevant to those seen in DS. Many drugs and small molecules have been shown to rescue the LM deficits, but little is known about the associated molecular responses. Here, patterns of protein expression are described in hippocampus of Ts65Dn and euploid littermate controls exposed to a battery of LM and behavior tests with and without chronic treatment with the GABA A receptor α5 subunit-selective negative allosteric modulator, RO4938581, that rescued LM deficits. Levels of 91 proteins/protein modifications, selected for relevance to LM and synaptic plasticity, were measured: 44 of 52 abnormalities present in vehicle-treated Ts65Dn were corrected by RO4938581. Superimposing protein data onto the molecular pathway defining long-term potentiation (LTP) shows that profiles are consistent with both abnormal LTP in vehicle-treated Ts65Dn and its observed rescue by RO4938581. Lastly, comparing these results with those from Ts65Dn treated, using a different protocol, with the NMDA receptor antagonist, memantine, that also rescues LM impairments, identifies common and divergent responses to the two drugs. Expansion of this approach to include additional drugs and DS models would aid in determining critical protein abnormalities and in identifying cocktails of drugs and/or new drug targets that would be effective in clinical trials for ID in DS. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) is caused by triplication of chromosome 21 (HSA21). It is characterised by intellectual disability and impaired motor coordination that arise from changes in brain volume, structure and function. However, the contribution of each HSA21 gene to these various phenotypes and to the causal alterations in neuronal and synaptic structure and function are largely unknown. Here we have investigated the effect of overexpression of the HSA21 gene DSCAM (Down syndrome cell adhesion molecule), on glutamatergic synaptic transmission and motor coordination, using Drosophila expressing three copies of Dscam1 . Electrophysiological recordings of miniature and evoked excitatory junction potentials at the glutamatergic neuromuscular junction of Drosophila larvae showed that the extra copy of Dscam1 changed the properties of spontaneous and electrically-evoked transmitter release and strengthened short-term synaptic depression during high-frequency firing of the motor nerve. Behavioural analyses uncovered impaired locomotor coordination despite preserved gross motor function. This work identifies DSCAM as a candidate causative gene in DS that is sufficient to modify synaptic transmission and synaptic plasticity and cause a DS behavioural phenotype. [ABSTRACT FROM AUTHOR]

Mitochondria play a pivotal role in cellular energy-generating processes and are considered master regulators of cell life and death fate. Mitochondrial function integrates signalling networks in several metabolic pathways controlling neurogenesis and neuroplasticity. Indeed, dysfunctional mitochondria and mitochondrial-dependent activation of intracellular stress cascades are critical initiating events in many human neurodegenerative or neurodevelopmental diseases including Down syndrome (DS). It is well established that trisomy of human chromosome 21 can cause DS. DS is associated with neurodevelopmental delay, intellectual disability and early neurodegeneration. Recently, molecular mechanisms responsible for mitochondrial damage and energy deficits have been identified and characterized in several DS-derived human cells and animal models of DS. Therefore, therapeutic strategies targeting mitochondria could have great potential for new treatment regimens in DS. The purpose of this review is to highlight recent studies concerning mitochondrial impairment in DS, focusing on alterations of the molecular pathways controlling mitochondrial function. We will also discuss the effects and molecular mechanisms of naturally occurring and chemically synthetized drugs that exert neuroprotective effects through modulation of mitochondrial function and attenuation of oxidative stress. These compounds might represent novel therapeutic tools for the modulation of energy deficits in DS. [ABSTRACT FROM AUTHOR]

Abnormal dendritic spine structure and function is one of the most prominent features associated with neurodevelopmental disorders including Down syndrome (DS). Defects in both spine morphology and spine density may underlie alterations in neuronal and synaptic plasticity, ultimately affecting cognitive ability. Here we briefly examine the role of astrocytes in spine alterations and more specifically the involvement of astrocyte-secreted thrombospondin 1 (TSP-1) deficits in spine and synaptic pathology in DS. [ABSTRACT FROM AUTHOR]

Individuals with Williams syndrome and those with Down syndrome are both characterized by heightened social interest, although the manifestation is not always similar. Using a dot-probe task, we examined one possible source of difference: allocation of attention to facial expressions of emotion. Thirteen individuals with Williams syndrome (mean age = 19.2 years, range = 10–28.6), 20 with Down syndrome (mean age = 18.8 years, range = 12.1–26.3), and 19 typically developing children participated. The groups were matched for mental age (mean = 5.8 years). None of the groups displayed a bias to angry faces. The participants with Williams syndrome showed a selective bias toward happy faces, whereas the participants with Down syndrome behaved similarly to the typically developing participants with no such bias. Homogeneity in the direction of bias was markedly highest in the Williams syndrome group whose bias appeared to result from enhanced attention capture. They appeared to rapidly and selectively allocate attention toward positive facial expressions. The complexity of social approach behavior and the need to explore other aspects of cognition that may be implicated in this behavior in both syndromes is discussed. [ABSTRACT FROM AUTHOR]

Among Down syndrome (DS) children, 40–50% have congenital heart disease (CHD). Although trisomy 21 is not sufficient to cause CHD, three copies of at least part of chromosome 21 (Hsa21) increases the risk for CHD. In order to establish a genotype-phenotype correlation for CHD in DS, we built an integrated Hsa21 map of all described partial trisomy 21 (PT21) cases with sufficient indications regarding presence or absence of CHD ( n = 107), focusing on DS PT21 cases. We suggest a DS CHD candidate region on 21q22.2 (0.96 Mb), being shared by most PT21 cases with CHD and containing three known protein-coding genes ( DSCAM , BACE2 , PLAC4 ) and four known non-coding RNAs ( DSCAM-AS1 , DSCAM-IT1 , LINC00323 , MIR3197 ). The characterization of a DS CHD candidate region provides a useful approach to identify specific genes contributing to the pathology and to orient further investigations and possibly more effective therapy in relation to the multifactorial pathogenesis of CHD. [ABSTRACT FROM AUTHOR]

Background: The thyroid is the earliest endocrine structure to appear during human development, and thyroid hormones are necessary for proper organism development, in particular for the nervous system and heart, normal growth and skeletal maturation. To date a quantitative, validated transcriptional atlas of the whole normal human thyroid does not exist and the availability of a detailed expression map might be an excellent occasion to investigate the many features of the thyroid transcriptome. Results: We present a view at the molecular level of the normal human thyroid histology and physiology obtained by a systematic meta-analysis of all the available gene expression profiles for the whole organ. A quantitative transcriptome reference map was generated by using the TRAM (Transcriptome Mapper) software able to combine, normalize and integrate a total of 35 suitable datasets from different sources thus providing a typical reference expression value for each of the 27,275 known, mapped transcripts obtained. The experimental in vitro validation of data was performed by "Real-Time" reverse transcription polymerase chain reaction showing an excellent correlation coefficient (r = 0.93) with data obtained in silico. Conclusions: Our study provides a quantitative global reference portrait of gene expression in the normal human thyroid and highlights differential expression between normal human thyroid and a pool of non-thyroid tissues useful for modeling correlations between thyroidal gene expression and specific thyroid functions and diseases. The experimental in vitro validation supports the possible usefulness of the human thyroid transcriptome map as a reference for molecular studies of the physiology and pathology of this organ. [ABSTRACT FROM AUTHOR]

Ts1Cje mice have a segmental trisomy of chromosome 16 that is orthologous to human chromosome 21 and display Down syndrome-like cognitive impairments. Despite the occurrence of affective and emotional impairments in patients with Down syndrome, these parameters are poorly documented in Down syndrome mouse models, including Ts1Cje mice. Here, we conducted comprehensive behavioral analyses, including anxiety-, sociability-, and depression-related tasks, and biochemical analyses of monoamines and their metabolites in Ts1Cje mice. Ts1Cje mice showed enhanced locomotor activity in novel environments and increased social contact with unfamiliar partners when compared with wild-type littermates, but a significantly lower activity in familiar environments. Ts1Cje mice also exhibited some signs of decreased depression like-behavior. Furthermore, Ts1Cje mice showed monoamine abnormalities, including increased extracellular dopamine and serotonin, and enhanced catabolism in the striatum and ventral forebrain. This study constitutes the first report of deviated monoamine metabolism that may help explain the basis for abnormal behaviors, including the environmental stimuli-triggered hyperactivity, increased sociability and decreased depression-like behavior in Ts1Cje mice. [ABSTRACT FROM AUTHOR]

Patients with myeloid leukemia of Down syndrome (ML-DS) have favorable event-free survival (EFS), but experience significant treatment-related morbidity and mortality. ML-DS blast cells ex vivo have increased sensitivity to cytarabine (araC) and daunorubicin, suggesting that optimizing drug dosing may improve outcomes while reducing toxicity. The Children's Oncology Group (COG) AAML0431 trial consisted of 4 cycles of induction and 2 cycles of intensification therapy based on the treatment schema of the previous COG A2971 trial with several modifications. High-dose araC (HD-araC) was used in the second induction cycle instead of the intensification cycle, and 1 of 4 daunorubicin-containing induction cycles was eliminated. For 204 eligible patients, 5-year EFS was 89.9% and overall survival (OS) was 93.0%. The 5-year OS for 17 patients with refractory/relapsed leukemia was 34.3%. We determined the clinical significance of minimal residual disease (MRD) levels as measured by flow cytometry on day 28 of induction I. MRD measurements, available for 146 of the 204 patients, were highly predictive of treatment outcome; 5-year disease-free survival for MRD-negative patients (n = 125) was 92.7% vs 76.2% for MRD-positive patients (n = 21) (log-rank P = .011). Our results indicated that earlier use of HD-araC led to better EFS and OS in AAML0431 than in past COG studies. A 25% reduction in the cumulative daunorubicin dose did not impact outcome. MRD, identified as a new prognostic factor for ML-DS patients, can be used for risk stratification in future clinical trials. This trial was registered at www.clinicaltrials.gov as #NCT00369317. [ABSTRACT FROM AUTHOR]

Children with myeloid leukemia associated with Down syndrome (ML-DS) have superior outcome compared with non-DS patients, but suffer from higher constitutional cytotoxic drug susceptibility. We analyzed the outcome of 170 pediatric patients with ML-DS enrolled in the prospective, multicenter, open-label, nonrandomized ML-DS 2006 trial by Nordic Society for Pediatric Hematology and Oncology (NOPHO), Dutch Childhood Oncology Group (DCOG), and Acute Myeloid Leukemia-Berlin-Frankfurt-Münster (AML-BFM) study group. Compared with the historical control arm (reduced-intensity protocol for ML-DS patients from the AML-BFM 98 trial), treatment intensity was reduced by lowering the cumulative dose of etoposide (950 to 450 mg/m²) and intrathecal central nervous system prophylaxis while omitting maintenance therapy. Still, 5-year overall survival (89% ± 3% vs 90% ± 4%; Plog-rank = .64), event-free survival (EFS; 87% ± 3% vs 89% ± 4%; Plog-rank = .71), and cumulative incidence of relapse/nonresponse (CIR/NR; 6% ± 3% vs 6% ± 2%; PGray = .03) did not significantly differ between the ML-DS 2006 trial and the historical control arm. Poor early treatment response (5-year EFS, 58% ± 16% vs 88% ± 3%; Plog-rank = .0008) and gain of chromosome 8 (CIR/NR, 16% ± 7% vs 3% ± 2%, PGray = .02; 5-year EFS, 73% ± 8% vs 91% ± 4%, Plog rank = .018) were identified as independent prognostic factors predicting a worse EFS. Five of 7 relapsed patients (71%) with cytogenetic data had trisomy 8. Our study reveals prognostic markers for children with ML-DS and illustrates that reducing therapy did not impair excellent outcome. The trial was registered at EudraCT as #2007-006219-2. [ABSTRACT FROM AUTHOR]

Introduction: Invasive prenatal diagnosis (IPD) has long been used to prenatally diagnose Down syndrome (DS), but it is associated with a small risk of miscarriage. Noninvasive prenatal testing (NIPT) is a highly sensitive screening test using cell-free DNA in maternal blood for detection of DS without the risk of miscarriage, but it confers a small risk of false-positive and false-negative results. The implementation of these procedures into clinical practice requires an understanding of stakeholder preferences.Methods: A total of 69 health professionals (HPs) and 301 women took part in a discrete choice experiment (DCE) in which preferences for four prenatal test attributes - accuracy, time of results, risk of miscarriage and amount of information provided - were assessed. Conditional logit regression was used to analyse the data. Data on demographics and ranked preferences for test attributes was collected, and a direct choice question regarding NIPT, IPD or neither test was posed to participants.Results: The women showed a preference for test safety, whereas HPs prioritised test accuracy above all other attributes. When offered a direct choice of NIPT, IPD or neither test, women aged 35 years and older, those with previous miscarriage or who knew a child with DS were more likely to choose NIPT. Chinese women preferred NIPT, whereas Indian women preferred IPD.Conclusion: Our data highlights the need for patient-specific counselling, taking into account previous experiences and cultural factors. Since women and HPs prioritise different test attributes, it is essential that HPs recognise these differences in order to provide non-biased counselling. [ABSTRACT FROM AUTHOR]

Overexpression of the amyloid precursor protein (APP) gene on chromosome 21 in Down syndrome (DS) has been linked to increased brain amyloid levels and early-onset Alzheimer's disease (AD). An elderly man with phenotypic DS and partial trisomy of chromosome 21 (PT21) lacked triplication of APP affording an opportunity to study the role of this gene in the pathogenesis of dementia. Multidisciplinary studies between ages 66-72 years comprised neuropsychological testing, independent neurological exams, amyloid PET imaging with 11C-Pittsburgh compound-B (PiB), plasma amyloid-β (Aβ) measurements, and a brain autopsy examination. The clinical phenotype was typical for DS and his intellectual disability was mild in severity. His serial neuropsychological test scores showed less than a 3% decline as compared to high functioning individuals with DS who developed dementia wherein the scores declined 17-28% per year. No dementia was detected on neurological examinations. On PiB-PET scans, the patient with PT21 had lower PiB standard uptake values than controls with typical DS or sporadic AD. Plasma Aβ42 was lower than values for demented or non-demented adults with DS. Neuropathological findings showed only a single neuritic plaque and neurofibrillary degeneration consistent with normal aging but not AD. Taken together the findings in this rare patient with PT21 confirm the obligatory role of APP in the clinical, biochemical, and neuropathological findings of AD in DS. [ABSTRACT FROM AUTHOR]

Down syndrome characterized by trisomy of chromosome 21 is frequently associated with thyroid dysfunctions due to underlying autoimmune disorders. Hypothyroidism is the commonest thyroid dysfunction and hyperthyroidism, usually Graves' disease, is far less common. On literature review, we came across approximately 112 cases reported so far with the first such case report in 1946. The published data from India on hyperthyroidism in Down syndrome is of three case reports. We report one such patient, an adult male of 28 years who was administered Iodine-131 as a definitive treatment after 9-10 years of initial diagnosis. [ABSTRACT FROM AUTHOR]

Introduction: Down syndrome (DS), caused by human trisomy 21 (Ts21), can be considered as a prototypical model for understanding the effects of chromosomal aneuploidies in other diseases. Human chromosome 21 (Hsa21) is syntenically conserved with three regions in the mouse genome. Sources of data: A review of recent advances in genetic modeling and analysis of DS. Using Cre/loxP-mediated chromosome engineering, a substantial number of new mouse models of DS have recently been generated, which facilitates better understanding of disease mechanisms in DS. Areas of agreement: Based on evolutionary conservation, Ts21 can be modeled by engineered triplication of Hsa21 syntenic regions in mice. The validity of the models is supported by the exhibition of DS-related phenotypes. Areas of controversy: Although substantial progress has been made, it remains a challenge to unravel the relative importance of specific candidate genes and molecular mechanisms underlying the various clinical phenotypes. Growing points: Further understanding of mechanisms based on data from mouse models, in parallel with human studies, may lead to novel therapies for clinical manifestations of Ts21 and insights to the roles of aneuploidies in other developmental disorders and cancers. [ABSTRACT FROM AUTHOR]

We describe a fully automated pipeline for the morphometric phenotyping of mouse brains from μMRI data, and show its application to the Tc1 mouse model of Down syndrome, to identify new morphological phenotypes in the brain of this first transchromosomic animal carrying human chromosome 21. We incorporate an accessible approach for simultaneously scanning multiple ex vivo brains, requiring only a 3D-printed brain holder, and novel image processing steps for their separation and orientation. We employ clinically established multi-atlas techniques–superior to single-atlas methods–together with publicly-available atlas databases for automatic skull-stripping and tissue segmentation, providing high-quality, subject-specific tissue maps. We follow these steps with group-wise registration, structural parcellation and both Voxel- and Tensor-Based Morphometry–advantageous for their ability to highlight morphological differences without the laborious delineation of regions of interest. We show the application of freely available open-source software developed for clinical MRI analysis to mouse brain data: NiftySeg for segmentation and NiftyReg for registration, and discuss atlases and parameters suitable for the preclinical paradigm. We used this pipeline to compare 29 Tc1 brains with 26 wild-type littermate controls, imaged ex vivo at 9.4T. We show an unexpected increase in Tc1 total intracranial volume and, controlling for this, local volume and grey matter density reductions in the Tc1 brain compared to the wild-types, most prominently in the cerebellum, in agreement with human DS and previous histological findings. [ABSTRACT FROM AUTHOR]

This study examined the development of phonological recoding in short-term memory (STM) span tasks among two clinical groups with contrasting STM and language profiles: those with Down syndrome (DS) and Williams syndrome (WS). Phonological recoding was assessed by comparing: (1) performance on phonologically similar and dissimilar items (phonological similarity effects, PSE); and (2) items with short and long names (word length effects, WLE). Participant groups included children and adolescents with DS (n=29), WS (n=25) and typical development (n=51), all with average mental ages around 6 years. The group with WS, contrary to predictions based on their relatively strong verbal STM and language abilities, showed no evidence for phonological recoding. Those in the group with DS, with weaker verbal STM and language abilities, showed positive evidence for phonological recoding (PSE), but to a lesser degree than the typical group (who showed PSE and WLE). These findings provide new information about the memory systems of these groups of children and adolescents, and suggest that STM processes involving phonological recoding do not fit with the usual expectations of the abilities of children and adolescents with WS and DS. [ABSTRACT FROM AUTHOR]

The present study is an in-depth examination of receptive vocabulary in individuals with Down syndrome (DS) in comparison to control groups of individuals of similar nonverbal ability with typical development (TD) and non-specific etiology intellectual disability (ID). Verb knowledge was of particular interest, as it is known to be a predictor of later syntactic development. Fifty participants with DS, aged 10-21 years, 29 participants with ID, 10-21 years, and 29 participants with TD, 4-9 years, completed measures of receptive vocabulary (PPVT-4), nonverbal ability (Leiter-R), and phonological memory (Nonword Repetition subtest of the CTOPP). Groups were compared on percentage correct of noun, verb and attribute items on the PPVT-4. Results revealed that on verb items, the participants with ID performed significantly better than both participants with DS and TD, even when overall receptive vocabulary ability and phonological memory were held constant. Groups with DS and TD showed the same pattern of lexical knowledge, performing better on nouns than both verbs and attributes. In contrast, the group with ID performed similarly on nouns and verbs, but worse on attributes. [ABSTRACT FROM AUTHOR]

In the education of pupils with Down syndrome, "simplifying" literal talk and concrete stimulation have typically played a dominant role. This explorative study investigated the extent to which teachers stimulated abstract cognitive functions via inferential talk during book-sharing and how pupils with Down syndrome responded. Dyadic interactions (N=7) were videotaped, transcribed and coded to identify levels of abstraction in teacher utterances and to evaluate the adequacy of pupil responses. One-third of the teachers' utterances contained high levels of abstraction and promoted inferential talk. Six of the seven children predominantly responded in ways which revealed inferential thinking. Dialog excerpts highlighted individual, contextual and interactional factors contributing to variations in the findings. Contrary to previous claims, the children with Down syndrome in the current sample appear able to draw inferences beyond the "here-and-now" with teacher support. This finding highlights the educational relevance and importance of higher-order cognitive stimulation of pupils with intellectual disabilities, to foster independent metacognitive skills. [ABSTRACT FROM AUTHOR]

Background: Down syndrome incidence in humans increases dramatically with maternal age. This is mainly the result of increased meiotic errors, but factors such as differences in abortion rate may play a role as well. Since the meiotic error rate increases almost exponentially after a certain age, its contribution to the overall incidence aneuploidy may mask the contribution of other processes. Results: To focus on such selection mechanisms we investigated transmission in trisomic females, using data from mouse models and from Down syndrome humans. In trisomic females the a-priori probability for trisomy is independent of meiotic errors and thus approximately constant in the early embryo. Despite this, the rate of transmission of the extra chromosome decreases with age in females of the Ts65Dn and, as we show, for the Tc1 mouse models for Down syndrome. Evaluating progeny of 73 Tc1 births and 112 Ts65Dn births from females aged 130 days to 250 days old showed that both models exhibit a 3-fold reduction of the probability to transmit the trisomy with increased maternal ageing. This is concurrent with a 2-fold reduction of litter size with maternal ageing. Furthermore, analysis of previously reported 30 births in Down syndrome women shows a similar tendency with an almost three fold reduction in the probability to have a Down syndrome child between a 20 and 30 years old Down syndrome woman. Conclusions: In the two types of mice models for Down syndrome that were used for this study, and in human Down syndrome, older females have significantly lower probability to transmit the trisomy to the offspring. Our findings, taken together with previous reports of decreased supportive environment of the older uterus, add support to the notion that an older uterus negatively selects the less fit trisomic embryos. [ABSTRACT FROM AUTHOR]

The article focuses on the benefits of movement-based therapy for children with Down syndrome. It is stated that Individuals with Down syndrome often have thyroid and respiratory problems and the motor development of a child is affected in Down syndrome. It is mentioned that the mind and body is connected through the movement approach.

Cancer patients with Down syndrome (DS) are at increased risk for anthracycline-related cardiotoxicity. Mitochondrial DNA (mtDNA) alterations in hearts with-DS may contribute to anthracycline-related cardiotoxicity. Cardiac mtDNA and the mtDNA4977deletion were quantitated in samples with- (n = 11) and without-DS (n = 31). Samples with-DS showed 30% lower mtDNA (DSMT-ND1/18Sratio: 1.48 ± 0.72 versus non-DSMT-ND1/18Sratio: 2.10 ± 1.59;p = 0.647) and 30% higher frequency of the mtDNA4977deletion (DS% frequency mtDNA4977 deletion: 0.0086 ± 0.0166 versus non-DS% frequency mtDNA4977 deletion: 0.0066 ± 0.0124,p = 0.514) than samples without-DS. TheBACH1andmicroRNA-155(miR-155) genes are located in chromosome 21, and their products have demonstrated roles during oxidative stress.BACH1andmiR-155expression did not differ in hearts with- and without-DS. An association betweenBACH1andmiR-155expression was detected in hearts without-DS, suggesting alterations betweenBACH1-miR-155interactions in the DS settings. [ABSTRACT FROM AUTHOR]

We performed an innovative systematic meta-analysis of 41 gene expression profiles of normal human hippocampus to provide a quantitative transcriptome reference map of it, i.e. a reference typical value of expression for each of the 30,739 known mapped and the 16,258 uncharacterized (unmapped) transcripts. For this aim, we used the software called TRAM (Transcriptome Mapper), which is able to generate transcriptome maps based on gene expression data from multiple sources. We also analyzed differential expression by comparing the hippocampus with the whole brain transcriptome map to identify a typical expression pattern of this subregion compared with the whole organ. Finally, due to the fact that the hippocampus is one of the main brain region to be severely affected in trisomy 21 (the best known genetic cause of intellectual disability), a particular attention was paid to the expression of chromosome 21 (chr21) genes. Data were downloaded from microarray databases, processed, and analyzed using TRAM software. Among the main findings, the most over-expressed loci in the hippocampus are the expressed sequence tag cluster Hs.732685 and the member of the calmodulin gene family CALM2. The tubulin folding cofactor B (TBCB) gene is the best gene at behaving like a housekeeping gene. The hippocampus vs. the whole brain differential transcriptome map shows the over-expression of LINC00114, a long non-coding RNA mapped on chr21. The hippocampus transcriptome map was validated in vitro by assaying gene expression through several magnitude orders by "Real-Time" reverse transcription polymerase chain reaction (RT-PCR). The highly significant agreement between in silico and experimental data suggested that our transcriptome map may be a useful quantitative reference benchmark for gene expression studies related to human hippocampus. Furthermore, our analysis yielded biological insights about those genes that have an intrinsic over-/ under-expression in the hippocampus. [ABSTRACT FROM AUTHOR]

Objectives Oxidative stress (OS) may play a critical role in cell aging and neurologic disorders that are often seen in Down syndrome (DS) patients. The aim of this study was to determine the antioxidant enzyme level and lipoperoxidation status in blood from DS children. Design and methods In a cross-sectional study, we recruited a total of 36 DS children and 40 healthy controls (HCs). All subjects were free of infection according to the C reactive protein (CRP) value and routine peripheral blood profile. The activities of total superoxide dismutases (SODs), extracellular glutathione peroxidase (GPx3),malondialdehyde (MDA) and nitric oxide synthase (NOS) concentrations in peripheral blood were measured by spectrophotometric methods. The relationship of SOD and GPx3 was analyzed in the two groups. Results The two groups were similar with respect to age, gender and peripheral blood profiles. The total SOD activity was significantly increased, while the GPx3 activity was significantly reduced in the DS group compared to the HCs ( p = 0.000, p = 0.033 respectively). The MDA level was higher in DS children ( p = 0.013). There was no significant difference in NOS between DS and HCs ( p = 0.708). A significant negative correlation between GPx3 and SOD activity was identified in DS ( r = − 0.14, p = 0.018) but not in the HC group. Conclusions Abnormal redox metabolism takes place in DS individuals. Reducing GPx3 may be a compensatory mechanism of protection against intracellular OS. Moreover, monitoring of decreases in GPx3 activity may be a useful biomarker for evaluating OS in DS patients. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) is the most common cause of genetic intellectual disability, and the trisomy 21 is associated with more than 80 clinical traits, including higher risk for epilepsy. Several hypotheses have been put forward to explain the mechanisms underlying increased seizure susceptibility in DS: inherent structural brain abnormalities, abnormal cortical lamination, disruption of normal dendritic morphology, and underdeveloped synaptic profiles. A deficiency or loss of GABA inhibition is hypothesized to be one of the main alterations related to the epileptogenic process. Paradoxically, enhanced GABA inhibition has also been reported to promote seizures. One major functional abnormality observed in the brains of individuals and mouse models with DS appears to be an imbalance between excitatory and inhibitory neurotransmission, with excessive inhibitory brain function. This review discusses the GABAergic system in the human DS brain and the possible implication of the GABAergic network circuit in the epileptogenic process in individuals where the pathogenetic basis for epilepsy is unknown. [ABSTRACT FROM AUTHOR]

Our statistical analysis once again proves the absence of an age factor as a risk of having children with Down syndrome, and an increase in the birth of children with Down syndrome in mothers aged 19 to 35 is directly related to the increase in the number of births. [ABSTRACT FROM AUTHOR]