Haematology of Down syndrome

Postoperative evaluation of special needs and healthy patients with endodontic treatment under general anesthesia: a retrospective research

BACKGROUND

This retrospective clinical study was undertaken to comparatively evaluate the number of restorative treatments, endodontic treatments, and tooth extractions performed for patients under general anesthesia due to dental anxiety or special needs between 2015 and 2022 and to examine the pain, bleeding, nausea, and vomiting data of those patients.

METHODS

In total, 1165 patients underwent dental treatment under general anesthesia in the faculty hospital. Those under the age of 15 and with no endodontic procedure planned (n = 918) were excluded, followed by those with incomplete data (n = 25) and those without endodontic treatment (n = 25). Patients who underwent at least one endodontic treatment were finally included in the study (n = 184). Patients were divided into two groups: healthy and with special needs. Dental treatments were recorded as endodontic, restorative, and teeth extractions. Endodontic treatments were classified according to the tooth type (premolar, molar, and incisors). The composite restorations were classified as anterior, occlusal (O), occluso-distal (OD) or occluso-mesial (OM), and mesio-occluso-distal (MOD) restorations and patients' post-treatment pain, nausea, vomiting, and bleeding were recorded. The data were analyzed statistically.

RESULTS

Among the 184 patients included in the study, 70 (38%) were healthy, and 114 (62%) had special needs. Postoperative bleeding was observed more in patients with special needs (χ2 = 4.189, p < 0.05), whereas pain was observed more in healthy patients (U = 2922.00, p < 0.05). While the number of anterior, O, and MOD restorations was higher in patients with special needs, the number of OD or OM restorations was higher in healthy patients (χ2 = 74.877, p < 0.05).

CONCLUSIONS

Patients with special needs undergo a greater number of restorative treatments compared to control patients, which may be associated with the inadequate oral hygiene care of such patients. However, restorative treatment is mostly indicated for such patients in our faculty hospital, which may indicate that a conservative approach is taken. Additionally, the finding that postoperative bleeding was more severe in this group of patients compared to the control group in this study may emphasize the need to consider more possible complications after general anesthesia in these patients.

Chromosomal abnormalities associated with fetal pleural effusion (II): Specific and non-specific chromosome aberrations

Fetal pleural effusion has been reported to be associated with chromosomal abnormalities, genetic syndromes, obstructive uropathy, lymphatic vessel abnormalities such as Noonan syndrome, RASopathy and congenital lymphatic anomalies, thoracic cavity defects, Rh or ABO incompatibility, non-immune hydrops fetalis, infections, congenital cardiac anomalies, metabolic diseases and hematologic diseases such as α-thalassemia. This review provides a comprehensive view of specific and non-specific chromosome aberrations associated with fetal pleural effusion which is useful for genetic counseling and fetal therapy at prenatal diagnosis of fetal pleural effusion.

Survival outcomes of myeloid leukemia associated with Down syndrome and de novo acute myeloid leukemia in children: Experience from a single tertiary center in Thailand

Few studies have reported the survival outcomes of myeloid leukemia associated with Down syndrome (DS) in resource-limited countries. This study aimed to compare characteristics and survival outcomes of children with acute myeloid leukemia (AML) between those with and without DS in Thailand. The medical records of AML patients aged 0-15 years treated in a major tertiary center in Southern Thailand between October 1978 and December 2019 were reviewed retrospectively. The overall (OS) and event-free survivals (EFS) rates were calculated using the Kaplan-Meier method. A total of 362 AML patients were included, of which 41 (11.3%) had DS. The mean age at diagnosis of the DS patients was 2.5 ± 1.9 years and most of them (90.2%) were under the age of five. The DS patients had lower initial white blood cell counts and peripheral blasts compared to the non-DS patients. The AML-M7 subtype was more common in the DS than in the non-DS patients (80.5% vs. 9.1%, p < 0.01, respectively). The 5-year OS and EFS rates of the DS patients were lower compared to the non-DS patients (12.9% vs. 20.5%, p = 0.05 and 13.7% vs. 18.4%, p = 0.03, respectively). DS patients had a significantly higher rate of early and treatment-related deaths compared to non-DS patients (30.3% vs. 13.5%, p < 0.01 and 39.4% vs. 19.5%, p = 0.02, respectively). Over the study period, there were a decrease in early death rate and an increase in survival rates of DS patients, which suggests that chemotherapy regimens and supportive care have improved over time.

Fail-tests of DNA methylation clocks, and development of a noise barometer for measuring epigenetic pressure of aging and disease

This study shows that Elastic Net (EN) DNA methylation (DNAme) clocks have low accuracy of predictions for individuals of the same age and a low resolution between healthy and disease cohorts; caveats inherent in applying linear model to non-linear processes. We found that change in methylation of cytosines with age is, interestingly, not the determinant for their selection into the clocks. Moreover, an EN clock's selected cytosines change when non-clock cytosines are removed from the training data; as expected from optimization in a machine learning (ML) context, but inconsistently with the identification of health markers in a biological context. To address these limitations, we moved from predictions to measurement of biological age, focusing on the cytosines that on average remain invariable in their methylation through lifespan, postulated to be homeostatically vital. We established that dysregulation of such cytosines, measured as the sums of standard deviations of their methylation values, quantifies biological noise, which in our hypothesis is a biomarker of aging and disease. We term this approach a "noise barometer" - the pressure of aging and disease on an organism. These noise-detecting cytosines are particularly important as sums of SD on the entire 450K DNAme array data yield a random pattern through chronology. Testing how many cytosines of the 450K arrays become noisier with age, we found that the paradigm of DNAme noise as a biomarker of aging and disease remarkably manifests in ~1/4 of the total. In that large set even the cytosines that have on average constant methylation through age show increased SDs and can be used as noise detectors of the barometer.

Medical imaging utilization and associated radiation exposure in children with down syndrome

OBJECTIVE

To evaluate the frequency of medical imaging or estimated associated radiation exposure in children with Down syndrome.

METHODS

This retrospective cohort study included 4,348,226 children enrolled in six U.S. integrated healthcare systems from 1996-2016, 3,095 of whom were diagnosed with Down syndrome. We calculated imaging rates per 100 person years and associated red bone marrow dose (mGy). Relative rates (RR) of imaging in children with versus without Down syndrome were estimated using overdispersed Poisson regression.

RESULTS

Compared to other children, children with Down syndrome received imaging using ionizing radiation at 9.5 times (95% confidence interval[CI] = 8.2-10.9) the rate when age <1 year and 2.3 times (95% CI = 2.0-2.5) between ages 1-18 years. Imaging rates by modality in children <1 year with Down syndrome compared with other children were: computed tomography (6.6 vs. 2.0, RR = 3.1[95%CI = 1.8-5.1]), fluoroscopy (37.1 vs. 3.1, RR 11.9[95%CI 9.5-14.8]), angiography (7.6 vs. 0.2, RR = 35.8[95%CI = 20.6-62.2]), nuclear medicine (6.0 vs. 0.6, RR = 8.2[95% CI = 5.3-12.7]), radiography (419.7 vs. 36.9, RR = 11.3[95%CI = 10.0-12.9], magnetic resonance imaging(7.3 vs. 1.5, RR = 4.2[95% CI = 3.1-5.8]), and ultrasound (231.2 vs. 16.4, RR = 12.6[95% CI = 9.9-15.9]). Mean cumulative red bone marrow dose from imaging over a mean of 4.2 years was 2-fold higher in children with Down syndrome compared with other children (4.7 vs. 1.9mGy).

CONCLUSIONS

Children with Down syndrome experienced more medical imaging and higher radiation exposure than other children, especially at young ages when they are more vulnerable to radiation. Clinicians should consider incorporating strategic management decisions when imaging this high-risk population.

Blood cytology in children with down syndrome

Introduction

Down syndrome is associated with various congenital anomalies and metabolic alterations such as hematological alterations. Values for the major hematological indicators vary with age and sex, but these values have not been described for Mexican children with Down syndrome.

Objective

To describe the complete blood count (CBC) values of pediatric patients with Down syndrome in México and report the most common non-malignant hematological alterations.

Materials and methods

The analysis includes data from 450 patients with Down syndrome, 55.5% ware males, aged 0-18 years who were patients at the Mexican National Institute of Pediatrics and whose clinical charts included CBC panel results for the period January 2008 through March 2018.

Results

A total of 3438 CBC panels were analyzed with descriptive statistics to find the values and statistical dispersion of the major indicators, with percentiles, and reported separately by sex and age group. The most common non-malignant hematological alterations found were macrocytic anemia, leukopenia, lymphopenia, and thrombocytosis. There were differences in values in all three series.

Conclusions

The CBC panels and hematological alterations are summarized for patients with Down syndrome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03450-8.

DNA Methylation Alterations in Blood Cells of Toddlers with Down Syndrome

Recent research has provided evidence on genome-wide alterations in DNA methylation patterns due to trisomy 21, which have been detected in various tissues of individuals with Down syndrome (DS) across different developmental stages. Here, we report new data on the systematic genome-wide DNA methylation perturbations in blood cells of individuals with DS from a previously understudied age group—young children. We show that the study findings are highly consistent with those from the prior literature. In addition, utilizing relevant published data from two other developmental stages, neonatal and adult, we track a quasi-longitudinal trend in the DS-associated DNA methylation patterns as a systematic epigenomic destabilization with age.

Leukemia Risk in a Cohort of 3.9 Million Children with and without Down Syndrome

OBJECTIVE

To assess leukemia risks among children with Down syndrome in a large, contemporary cohort.

STUDY DESIGN

Retrospective cohort study including 3 905 399 children born 1996-2016 in 7 US healthcare systems or Ontario, Canada, and followed from birth to cancer diagnosis, death, age 15 years, disenrollment, or December 30, 2016. Down syndrome was identified using International Classification of Diseases, Ninth and Tenth Revisions, diagnosis codes. Cancer diagnoses were identified through linkages to tumor registries. Incidence and hazard ratios (HRs) of leukemia were estimated for children with Down syndrome and other children adjusting for health system, child's age at diagnosis, birth year, and sex.

RESULTS

Leukemia was diagnosed in 124 of 4401 children with Down syndrome and 1941 of 3 900 998 other children. In children with Down syndrome, the cumulative incidence of acute myeloid leukemia (AML) was 1405/100 000 (95% CI 1076-1806) at age 4 years and unchanged at age 14 years. The cumulative incidence of acute lymphoid leukemia in children with Down syndrome was 1059/100 000 (95% CI 755-1451) at age 4 and 1714/100 000 (95% CI 1264-2276) at age 14 years. Children with Down syndrome had a greater risk of AML before age 5 years than other children (HR 399, 95% CI 281-566). Largest HRs were for megakaryoblastic leukemia before age 5 years (HR 1500, 95% CI 555-4070). Children with Down syndrome had a greater risk of acute lymphoid leukemia than other children regardless of age (<5 years: HR 28, 95% CI 20-40, ≥5 years HR 21, 95% CI 12-38).

CONCLUSIONS

Down syndrome remains a strong risk factor for childhood leukemia, and associations with AML are stronger than previously reported.

Fetal Hepatomegaly: Causes and Associations

Fetal hepatomegaly is associated with significant fetal morbidity and mortality. However, hepatomegaly might be overlooked when numerous other fetal anomalies are present, or it might not be noticed when it is an isolated entity. As the largest solid organ in the abdomen, the liver can be seen well with US or MRI, and the normal imaging characteristics are well described. The length of the fetal liver, which can be used to identify hepatomegaly, can be determined by measuring the liver from the diaphragm to the tip of the right lobe in the sagittal plane. Fetal hepatomegaly is seen with infection, transient abnormal myelopoiesis, liver storage and deposition diseases, some syndromes, large liver tumors, biliary atresia, and anemia. Some of these diagnoses are treatable during the fetal period. Attention to the associated findings and specific hepatic and nonhepatic imaging characteristics can help facilitate more accurate diagnoses and appropriate patient counseling.^©RSNA, 2020.

The genome-wide impact of trisomy 21 on DNA methylation and its implications for hematopoiesis

Down syndrome is associated with genome-wide perturbation of gene expression, which may be mediated by epigenetic changes. We perform an epigenome-wide association study on neonatal bloodspots comparing 196 newborns with Down syndrome and 439 newborns without Down syndrome, adjusting for cell-type heterogeneity, which identifies 652 epigenome-wide significant CpGs (P < 7.67 × 10-8) and 1,052 differentially methylated regions. Differential methylation at promoter/enhancer regions correlates with gene expression changes in Down syndrome versus non-Down syndrome fetal liver hematopoietic stem/progenitor cells (P < 0.0001). The top two differentially methylated regions overlap RUNX1 and FLI1, both important regulators of megakaryopoiesis and hematopoietic development, with significant hypermethylation at promoter regions of these two genes. Excluding Down syndrome newborns harboring preleukemic GATA1 mutations (N = 30), identified by targeted sequencing, has minimal impact on the epigenome-wide association study results. Down syndrome has profound, genome-wide effects on DNA methylation in hematopoietic cells in early life, which may contribute to the high frequency of hematological problems, including leukemia, in children with Down syndrome.

Transient abnormal myelopoiesis in pediatrics with trisomy 21

Transient abnormal myelopoiesis is common among Down syndrome patients. Although no therapeutic measures are required, close monitoring of comorbidities such as gastrointestinal bleeding is required. Long-term follow-up is promising for a healthy future and reduced requirement of unnecessary therapeutic measures including chemotherapy and remission of the pathology.

Characteristics of adults with Down syndrome hospitalised in Spanish internal medicine departments during 2005-2014

INTRODUCTION AND OBJECTIVES

The clinical problems of adults with Down syndrome seem to differ from those of the general population. To better understand these differences, we list the demographic and clinical characteristics of adults with Down syndrome admitted to Spanish internal medicine departments during 2005-2014.

PATIENTS AND METHODS

We conducted an observational retrospective study using data collected from the minimum basic data set on hospitalisation episodes of adults with Down syndrome in the internal medicine departments of Spain's National Health System from 2005 to 2014. We analysed the patients' epidemiological, clinical and societal data.

RESULTS

A total of 7548 hospitalisation episodes from 3786 patients were recorded. Some 56.6% of the patients were male with a mean age (±SD) of 47±13 years, and 715 of the patients died (18.9%). The age-adjusted mortality was 26.6%, and the mean stay was 9.6±12 days. The hospitalisation was for respiratory disease in 3684 episodes (48.8%) and for cardiac origin in 760 (10%). The most common comorbidities were hypothyroidism (27.1%, 2043 episodes), epilepsy (24.1%, 1819 episodes) and dementia (15.4%, 1162 episodes).

CONCLUSIONS

The hospitalisation of adults with Down syndrome in internal medicine departments has increased in the past decade. Although the reasons for hospitalisation, mean stay and cost per episode for this population are similar to those of the general population treated by internal medicine departments, the age-adjusted hospital mortality was significantly greater.

Classification of acute myeloid leukemia

The World Health Organization (WHO) Classification of Tumors of Hematopoietic and Lymphoid Tissues was revised in 2017 on the basis of recent high-throughput sequencing and gene expression data on hematologic malignancies. This review explores the current WHO classification of acute myeloid leukemia (AML) and related precursor neoplasms, highlighting the changes made in the current edition and focusing on the diagnosis of AML.

Multiorgan involvement and management in children with Down syndrome

AIM

To review multiorgan involvement and management in children with Down syndrome (DS).

METHODS

A literature review of articles from 1980 to 2019 using the MEDLINE interface of PubMed was performed using the following search terms- [Down syndrome] or [Trisomy 21] AND [Cardiology] or [Respiratory] or [neurodevelopment] or [epilepsy] or [musculoskeletal] or [immune system] or [haematological] or [endocrine] or [gastrointestinal] or [ophthalmological] or [Ear Nose Throat] or [dermatology] or [renal].

RESULTS

Congenital heart disease particularly septal defects occur in over 60% of infants with DS and 5%-34% of infants develop persistent pulmonary hypertension of the newborn irrespective of a diagnosis of congenital heart disease. Early recognition and management of aspiration, obstructive sleep apnoea and recurrent lower respiratory tract infections (LRTI) could reduce risk of developing pulmonary hypertension in later childhood. Children with DS have an increased risk of autistic spectrum disorder, attention deficit disorder and epilepsy particularly infantile spasms, which are associated with poor neurodevelopmental outcomes. Congenital anomalies of the gastrointestinal and renal system as well as autoimmune diseases, coeliac disease, arthropathy, thyroid dysfunction fold diabetes mellitus and dermatological conditions are more common. Hearing and visual anomalies are also well recognised association with DS (Table 1).

CONCLUSION

Children with DS are at an increased risk of multiorgan comorbidities. Organ-specific health surveillance may provide holistic care for the children and families with DS throughout childhood.

Pathologic Features of Down Syndrome Myelodysplastic Syndrome and Acute Myeloid Leukemia: A Report From the Children's Oncology Group Protocol AAML0431

CONTEXT.—

Detailed diagnostic features of acute myeloid leukemia in Down syndrome are lacking, leading to potential misdiagnoses as standard acute myeloid leukemia occurring in patients with Down syndrome.

OBJECTIVE.—

To evaluate diagnostic features of acute myeloid leukemia and myelodysplastic syndrome in patients with Down syndrome.

DESIGN.—

Diagnostic bone marrow samples from 163 patients enrolled in the Children's Oncology Group study AAML0431 were evaluated by using central morphologic review and institutional immunophenotyping. Results were compared to overall survival, event-free survival, GATA1 mutation status, cytogenetics, and minimal residual disease results.

RESULTS.—

Sixty myelodysplastic syndrome and 103 acute myeloid leukemia samples were reviewed. Both had distinctive features compared to those of patients without Down syndrome. They showed megakaryocytic and erythroid but little myeloid dysplasia, and marked megakaryocytic hyperplasia with unusual megakaryocyte morphology. In acute myeloid leukemia cases, megakaryoblastic differentiation of blasts was most common (54 of 103, 52%); other cases showed erythroblastic (11 of 103, 11%), mixed erythroid/megakaryoblastic (20 of 103, 19%), or no differentiation (10 of 103, 10%). Myelodysplastic syndrome and acute myeloid leukemia cases had similar event-free survival and overall survival. Leukemic subgroups showed interesting, but not statistically significant, trends for survival and minimal residual disease. Cases with institutional diagnoses of French American British M1-5 morphology showed typical features of Down syndrome disease, with survival approaching that of other cases.

CONCLUSIONS.—

Myelodysplastic syndrome and acute myeloid leukemia in Down syndrome display features that allow discrimination from standard cases of disease. These distinctions are important for treatment decisions, and for understanding disease pathogenesis. We propose specific diagnostic criteria for Down syndrome-related subtypes of acute myeloid leukemia and myelodysplastic syndrome.

Induced Pluripotent Stem Cells and Their Use in Human Models of Disease and Development

The discovery of somatic cell nuclear transfer proved that somatic cells can carry the same genetic code as the zygote, and that activating parts of this code are sufficient to reprogram the cell to an early developmental state. The discovery of induced pluripotent stem cells (iPSCs) nearly half a century later provided a molecular mechanism for the reprogramming. The initial creation of iPSCs was accomplished by the ectopic expression of four specific genes (OCT4, KLF4, SOX2, and c-Myc; OSKM). iPSCs have since been acquired from a wide range of cell types and a wide range of species, suggesting a universal molecular mechanism. Furthermore, cells have been reprogrammed to iPSCs using a myriad of methods, although OSKM remains the gold standard. The sources for iPSCs are abundant compared with those for other pluripotent stem cells; thus the use of iPSCs to model the development of tissues, organs, and other systems of the body is increasing. iPSCs also, through the reprogramming of patient samples, are being used to model diseases. Moreover, in the 10 years since the first report, human iPSCs are already the basis for new cell therapies and drug discovery that have reached clinical application. In this review, we examine the generation of iPSCs and their application to disease and development.

Bleeding Disorders in Congenital Syndromes

Pediatricians provide a medical home for children with congenital syndromes who often need complex multidisciplinary care. There are some syndromes associated with thrombocytopenia, inherited platelet disorders, factor deficiencies, connective tissue disorders, and vascular abnormalities, which pose a real risk of bleeding in affected children associated with trauma or surgeries. The risk of bleeding is not often an obvious feature of the syndrome and not well documented in the literature. This makes it especially hard for pediatricians who may care for a handful of children with these rare congenital syndromes in their lifetime. This review provides an overview of the etiology of bleeding in the different congenital syndromes along with a concise review of the hematologic and nonhematologic clinical manifestations. It also highlights the need and timing of diagnostic evaluation to uncover the bleeding risk in these syndromes emphasizing a primary care approach.

Transient Abnormal Myelopoiesis and AML in Down Syndrome: an Update

Children with constitutional trisomy 21 (Down syndrome (DS)) have a unique predisposition to develop myeloid leukaemia of Down syndrome (ML-DS). This disorder is preceded by a transient neonatal preleukaemic syndrome, transient abnormal myelopoiesis (TAM). TAM and ML-DS are caused by co-operation between trisomy 21, which itself perturbs fetal haematopoiesis and acquired mutations in the key haematopoietic transcription factor gene GATA1. These mutations are found in almost one third of DS neonates and are frequently clinically and haematologcially 'silent'. While the majority of cases of TAM undergo spontaneous remission, ∼10 % will progress to ML-DS by acquiring transforming mutations in additional oncogenes. Recent advances in the unique biological, cytogenetic and molecular characteristics of TAM and ML-DS are reviewed here.

Effect of dual pulmonary vasodilator therapy in pulmonary arterial hypertension associated with congenital heart disease: a retrospective analysis

BACKGROUND

Patients with pulmonary arterial hypertension (PAH) are managed according to evidence-based treatment guidelines.

METHODS AND RESULTS

In this single-centre retrospective analysis, we examined outcomes of patients with PAH caused by congenital heart disease (PAH-CHD) with respect to exercise capacity and survival of adults treated with either bosentan or sildenafil monotherapy or bosentan-sildenafil dual therapy between January 2007 and January 2014. Of the 82 patients analysed, 29 had Down syndrome; 54 (65.8%) received bosentan monotherapy, 16 (19.5%) sildenafil monotherapy and 12 (14.6%) dual therapy. Mean treatment duration was 2.5 years for all patients and 4.1 years for 38 patients treated for ≥2 years. Pooled patient and treatment data showed initial improvement followed by stabilisation in mean 6 min walk distance (6MWD). For Down and non-Down patients, mean 6MWD increased and then stabilised on bosentan monotherapy. Mean 6MWD of patients on dual therapy at the time of analysis was 246.3 m before PAH-specific therapy initiation, 211.9 m immediately prior to addition of a second therapy and 214.4 m at last visit while on dual therapy. 1, 2 and 3-year survival rates for all patients from time of treatment initiation were 96%, 87% and 80%, respectively.

CONCLUSIONS

For the majority of patients, monotherapy with a PAH-specific medication provided improved and sustained exercise benefits. For the small percentage of patients who required it, add-on therapy appeared to prevent further deterioration in exercise capacity but did not improve 6MWD.

Prenatal therapy in transient abnormal myelopoiesis: a systematic review

OBJECTIVE

To systematically review current evidence regarding prenatal diagnosis and management of transient abnormal myelopoiesis (TAM) in fetuses with trisomy 21. A novel case of GATA1-positive TAM, in which following serial in utero blood transfusion clinical improvement and postnatal remission were observed, is included.

SEARCH STRATEGY AND DATA COLLECTION

A systematic search of electronic databases (inception to October 2014) and reference lists, hand-searching of journals and expert contact. All confirmed cases of prenatal TAM were included for analysis. Data on study characteristics, design and quality were obtained.

RESULTS

Of 73 potentially relevant citations identified, 22 studies were included, describing 39 fetuses. All studies included comprised single case or small cohort studies; overall quality was 'very low'. Fetal/neonatal outcome was poor; 12 stillbirths (30.8%), 4 neonatal deaths (10.2%) and 7 infant deaths (17.9%). In two cases, the pregnancy was terminated (5.1%). TAM was primarily detected in the third trimester (79.4%), and in 14 a retrospective diagnosis was made postpartum. Ultrasound features indicative of TAM included hepatomegaly±splenomegaly (79.5%), hydrops fetalis (30.8%), pericardial effusion (23.1%) and aberrant liquor volume (15.4%). When performed, liver function tests were abnormal in 91.6% of cases.

CONCLUSIONS

Prenatal TAM presents a challenging diagnosis, and prognosis is poor, with consistently high mortality. A low threshold to measure haematological and biochemical markers is advised when clinical features typical of TAM are detected in the context of trisomy 21. Larger prospective studies are warranted to accurately ascertain the role of GATA1 analysis and potential value of prenatal therapy.

Evaluation of extracellular adenine nucleotides hydrolysis in platelets and biomarkers of oxidative stress in Down syndrome individuals

PURPOSE

Down syndrome (DS) is caused by the triplication of chromosome 21. Studies have demonstrated platelets abnormalities and oxidative stress in DS subjects. The enzymes NTPDase, 5'-nucleotidase and adenosine deaminase (ADA) represent an important therapeutic target since they interfere in the extracellular nucleotide pool altering platelet functions. In this study, we evaluated the ectonucleotidases activities and oxidative stress parameters in samples of DS and healthy individuals.

METHODS AND RESULTS

The population consisted of 28 subjects with DS and 28 healthy subjects as a control group. Blood was obtained from each subject and used for platelet and serum preparation. NTPDase activity using ATP as substrate was increased in platelets of DS patients in relation to the control group; however, no alterations were observed in the ADP hydrolysis. A decrease in the 5'-nucleotidase activity and an increase in the ADA activity was observed in platelet of DS subjects when compared to healthy individuals (P<0.05). The lipid peroxidation and total thiol content was decreased in serum of DS individuals. Furthermore, superoxide dismutase and catalase activities were increased in whole blood of this group (P<0.05).

CONCLUSION

Alterations in the ectonucleotidase activities in platelets as well as changes in the oxidative stress parameters may contribute to the clinical features of DS.

Exome sequencing identifies putative drivers of progression of transient myeloproliferative disorder to AMKL in infants with Down syndrome

Some neonates with Down syndrome (DS) are diagnosed with self-regressing transient myeloproliferative disorder (TMD), and 20% to 30% of those progress to acute megakaryoblastic leukemia (AMKL). We performed exome sequencing in 7 TMD/AMKL cases and copy-number analysis in these and 10 additional cases. All TMD/AMKL samples contained GATA1 mutations. No exome-sequenced TMD/AMKL sample had other recurrently mutated genes. However, 2 of 5 TMD cases, and all AMKL cases, showed mutations/deletions other than GATA1, in genes proven as transformation drivers in non-DS leukemia (EZH2, APC, FLT3, JAK1, PARK2-PACRG, EXT1, DLEC1, and SMC3). One patient at the TMD stage revealed 2 clonal expansions with different GATA1 mutations, of which 1 clone had an additional driver mutation. Interestingly, it was the other clone that gave rise to AMKL after accumulating mutations in 7 other genes. Data suggest that GATA1 mutations alone are sufficient for clonal expansions, and additional driver mutations at the TMD stage do not necessarily predict AMKL progression. Later in infancy, leukemic progression requires "third-hit driver" mutations/somatic copy-number alterations found in non-DS leukemias. Putative driver mutations affecting WNT (wingless-related integration site), JAK-STAT (Janus kinase/signal transducer and activator of transcription), or MAPK/PI3K (mitogen-activated kinase/phosphatidylinositol-3 kinase) pathways were found in all cases, aberrant activation of which converges on overexpression of MYC.

Prominent megakaryocytic dysplasia after regression of transient abnormal myelopoiesis associated with GATA-1 mutation

About a quarter of children with Down syndrome and transient abnormal myelopoiesis (TAM) progress to acute megakaryoblastic leukemia (AMKL). We describe isolated dysmegakaryopoiesis despite complete resolution of TAM in an 18-month-old girl, who developed AMKL 6 months later.

How I manage neonatal thrombocytopenia

Although neonatal thrombocytopenia (platelet count < 150×10(9) /l) is a common finding in hospital practice, a careful clinical history and examination of the blood film is often sufficient to establish the diagnosis and guide management without the need for further investigations. In preterm neonates, early-onset thrombocytopenia (<72h) is usually secondary to antenatal causes, has a characteristic pattern and resolves without complications or the need for treatment. By contrast, late-onset thrombocytopenia in preterm neonates (>72h) is nearly always due to post-natally acquired bacterial infection and/or necrotizing enterocolitis, which rapidly leads to severe thrombocytopenia (platelet count<50×10(9) /l). Thrombocytopenia is much less common in term neonates and the most important cause is neonatal alloimmune thrombocytopenia (NAIT), which confers a high risk of perinatal intracranial haemorrhage and long-term neurological disability. Prompt diagnosis and transfusion of human platelet antigen-compatible platelets is key to the successful management of NAIT. Recent studies suggest that more than half of neonates with severe thrombocytopenia receive platelet transfusion(s) based on consensus national or local guidelines despite little evidence of benefit. The most pressing problem in management of neonatal thrombocytopenia is identification of safe, effective platelet transfusion therapy and controlled trials are urgently needed.

Anemia in children with down syndrome

Background. Iron deficiency anemia impacts on cognitive development. The objective of this study was to determine the prevalence of anemia and iron deficiency in children with Down syndrome and identify risk factors for anemia. Methods. We conducted a prolective cross-sectional study of children attending a multidisciplinary Down syndrome medical center. One hundred and forty nine children with Down syndrome aged 0–20 years were enrolled in the study. Information obtained included a medical history, physical and developmental examination, nutritional assessment, and the results of blood tests. Results. Of the patients studied, 8.1% were found to have anemia. Among the 38 children who had iron studies, 50.0% had iron deficiency. In a multivariate analysis, Arab ethnicity and low weight for age were significantly associated with anemia. Gender, height, the presence of an eating disorder, and congenital heart disease were not risk factors for anemia. Conclusions. Children with Down syndrome are at risk for anemia and iron deficiency similar to the general population. Children with Down syndrome should be monitored for anemia and iron deficiency so that prompt intervention can be initiated.

Germinal and Somatic Trisomy 21 Mosaicism: How Common is it, What are the Implications for Individual Carriers and How Does it Come About?

It is well known that varying degrees of mosaicism for Trisomy 21, primarily a combination of normal and Trisomy 21 cells within individual tissues, may exist in the human population. This involves both Trisomy 21 mosaicism occurring in the germ line and Trisomy 21 mosaicism documented in different somatic tissues, or indeed a combination of both in the same subjects. Information on the incidence of Trisomy 21 mosaicism in different tissue samples from people with clinical features of Down syndrome as well as in the general population is, however, still limited. One of the main reasons for this lack of detailed knowledge is the technological problem of its identification, where in particular low grade/cryptic Trisomy 21 mosaicism, i.e. occurring in less than 3-5% of the respective tissues, can only be ascertained by fluorescence in situ hybridization (FISH) methods on large cell populations from the different tissue samples.In this review we summarize current knowledge in this field with special reference to the question on the likely incidence of germinal and somatic Trisomy 21 mosaicism in the general population and its mechanisms of origin. We also highlight the reproductive and clinical implications of this type of aneuploidy mosaicism for individual carriers. We conclude that the risk of begetting a child with Trisomy 21 Down syndrome most likely is related to the incidence of Trisomy 21 cells in the germ line of any carrier parent. The clinical implications for individual carriers may likewise be dependent on the incidence of Trisomy 21 in the relevant somatic tissues. Remarkably, for example, there are indications that Trisomy 21 mosaicism will predispose carriers to conditions such as childhood leukemia and Alzheimer's Disease but there is on the other hand a possibility that the risk of solid cancers may be substantially reduced.

A comparison of acute lymphoblastic leukemia in Down syndrome and non-Down syndrome children: the role of trisomy 21

Down syndrome (DS), which occurs once in every 800 births, is associated with a trisomy on locus 21. Among the many aberrations caused by DS, including shortened stature and distorted facies, are several blood dyscrasias, including childhood leukemias-namely, acute myeloid leukemia (AML) and acute lymphoblastic, or lymphocytic, leukemia (ALL). One focus of the diagnosis of ALL is to distinguish it from AML.The benefits of immunophenotyping extend to treatment as well. ALL is associated with an inherited trisomy 21 in DS children (ALL-DS) and with acquired trisomies, +21, 8, and 13, in non-DS children (ALL-NDS). The differences in treatment, outcome, and prognosis between ALL-DS and ALL-NDS can be attributed to the interaction of their respective trisomies with several genetic mutations, including one on the GATA1 growth factor transcription gene. Other mutations are the gene fusion at TEL/AML1, and a new mutation found, which labels the Janus Kinase gene or JAK2 as on oncogenic precursor, which when associated with the B-cell precursor gene or BCP is highly leukomogenic. The treatments for the 2 groups have been based on quality of risk, with ALL-DS children having the highest risk along with the poorest prognosis, but alterations in medication regimens have brought treatment outcomes to near equality. It is worthwhile to study the trisomy 21 because in the future it may provide an understanding of all blood dyscrasias.

Hematological abnormalities in adult patients with Down's syndrome

BACKGROUND

There is a paucity of data regarding hematological abnormalities in adults with Down's syndrome (DS).

AIMS

We aimed to characterize hematological abnormalities in adult patients with DS and determine their long-term significance.

METHODS

We retrospectively studied a cohort of nine DS patients referred to the adult hematology service in our institution between May 2001 and April 2008. Data collected were: full blood count (FBC), comorbidities, investigations performed, duration of follow-up and outcome to most recent follow-up.

RESULTS

Median follow-up was 26 months (9-71). Of the nine patients, two had myelodysplastic syndrome (MDS) at presentation. Of these, one progressed, with increasing marrow failure, and requiring support with transfusions and gCSF. The remaining eight patients, with a variety of hematological abnormalities including leukopenia, macrocytosis, and thrombocytopenia, had persistently abnormal FBCs. However there was no evidence of progression, and no patient has evolved to acute myeloid leukemia (AML).

CONCLUSIONS

MDS is a complication of DS and may require supportive therapy. However, minor hematological abnormalities are common in adult DS patients, and may not signify underlying marrow disease.

Primary care for children and adolescents with Down syndrome

This article reviews the general health care guidelines pertaining to pediatric patients with Down syndrome and presents, in a systems-based approach, an update of the current evidence behind these guidelines. To ensure the best possible long-term outcome for these patients, clinicians should provide routine well-child examinations and immunizations while maintaining a high index of suspicion for comorbid conditions more common in Down syndrome. The primary care provider should be prepared to provide information on community resources, to coordinate care with subspecialists, and to refer to early intervention services as soon as the diagnosis is made.

Thrombocytopenia in the neonate

Thrombocytopenia is one of the commonest haematological problems in neonates, affecting at least 25% of all admissions to neonatal intensive care units (NICUs) [Murray NA, Howarth LJ, McCloy MP et al. Platelet transfusion in the management of severe thrombocytopenia in neonatal intensive care unit patients. Transfus Med 2002;12:35-41; Garcia MG, Duenas E, Sola MC et al. Epidemiologic and outcome studies of patients who received platelet transfusions in the neonatal intensive care unit. J Perinatol 2001;21:415-20; Del Vecchio A, Sola MC, Theriaque DW et al. Platelet transfusions in the neonatal intensive care unit: factors predicting which patients will require multiple transfusions. Transfusion 2001;41:803-8]. Although a long list of disorders associated with neonatal thrombocytopenia can be found in many textbooks, newer classifications based on the timing of onset of thrombocytopenia (early vs. late) are more useful for planning diagnostic investigations and day-to-day management. The mainstay of treatment of neonatal thrombocytopenia remains platelet transfusion although it is important to note that no studies have yet shown clinical benefit of platelet transfusion in this setting. Indeed some reports even suggest that there may be significant adverse effects of platelet transfusion in neonates, including increased mortality, and that the effects of transfusion may differ in different groups of neonates with similar degrees of thrombocytopenia [Bonifacio L, Petrova A, Nanjundaswamy S, Mehta R. Thrombocytopenia related neonatal outcome in preterms. Indian J Pediatr 2007;74:269-74; Kenton AB, Hegemier S, Smith EO et al. Platelet transfusions in infants with necrotizing enterocolitis do not lower mortality but may increase morbidity. J Perinatol 2005;25:173-7]. There is also considerable variation in transfusion practice between different countries and between different neonatal units. Here we review recent progress in understanding the prevalence, causes and pathogenesis of thrombocytopenia in the newborn, the clinical consequences of thrombocytopenia and developments in neonatal platelet transfusion.