Prevalence, neonatal characteristics, and first-year mortality of Down syndrome: a national study

Neurobehavioral dysfunction in a mouse model of Down syndrome: upregulation of cystathionine β-synthase, H2S overproduction, altered protein persulfidation, synaptic dysfunction, endoplasmic reticulum stress, and autophagy

Down syndrome (DS) is a genetic condition where the person is born with an extra chromosome 21. DS is associated with accelerated aging; people with DS are prone to age-related neurological conditions including an early-onset Alzheimer's disease. Using the Dp(17)3Yey/ + mice, which overexpresses a portion of mouse chromosome 17, which encodes for the transsulfuration enzyme cystathionine β-synthase (CBS), we investigated the functional role of the CBS/hydrogen sulfide (H2S) pathway in the pathogenesis of neurobehavioral dysfunction in DS. The data demonstrate that CBS is higher in the brain of the DS mice than in the brain of wild-type mice, with primary localization in astrocytes. DS mice exhibited impaired recognition memory and spatial learning, loss of synaptosomal function, endoplasmic reticulum stress, and autophagy. Treatment of mice with aminooxyacetate, a prototypical CBS inhibitor, improved neurobehavioral function, reduced the degree of reactive gliosis in the DS brain, increased the ability of the synaptosomes to generate ATP, and reduced endoplasmic reticulum stress. H2S levels in the brain of DS mice were higher than in wild-type mice, but, unexpectedly, protein persulfidation was decreased. Many of the above alterations were more pronounced in the female DS mice. There was a significant dysregulation of metabolism in the brain of DS mice, which affected amino acid, carbohydrate, lipid, endocannabinoid, and nucleotide metabolites; some of these alterations were reversed by treatment of the mice with the CBS inhibitor. Thus, the CBS/H2S pathway contributes to the pathogenesis of neurological dysfunction in DS in the current animal model.

Death of children with Down syndrome by gestational age and cause

BACKGROUND

We often encounter preterm infants with Down syndrome (DS) who die in the neonatal intensive care unit (NICU). In this study, we examined survival until NICU discharge and assessed the developmental prognosis of preterm infants with DS.

METHODS

We retrospectively reviewed 416 infants with DS hospitalized during the past 27 years at our NICU.

RESULTS

Death occurred in 8/20 (40%) infants at <32 weeks' gestation, 11/23 (48%) at 32-33 weeks, 9/99 (9%) at 34-36 weeks, and 9/274 (3%) at >36 weeks. In total, 84% of infants who died and 25% of those who survived had a non-reassuring fetal status (p < 0.001). Sex, small-for-gestational-age status, and postnatal transport were not associated with death. The main causes of death were bronchopulmonary dysplasia in 4/8 (50%) infants at <32 weeks' gestation, transient abnormal myelopoiesis in 11/20 (55%) and lymphatic dysplasia in 6/20 (30%) at 32-36 weeks, and varied causes at >36 weeks. Among survivors born at <34 weeks' gestation, 6/19 (32%) aged >2 years had moderate or severe cerebral palsy.

CONCLUSIONS

These data on the high mortality and morbidity of preterm infants with DS may be useful for patient treatment and parent counseling in NICUs treating critically ill infants.

IMPACT

Most infants with Down syndrome born at <34 weeks' gestation are born by cesarean section because of the non-reassuring fetal status. The mortality rate before discharge for infants with Down syndrome born at <34 weeks' gestation was 40%, and 30% of survivors developed moderate or severe cerebral palsy. The risk of death due to bronchopulmonary dysplasia and pulmonary hypertension was high in very preterm infants with Down syndrome despite the absence of chorioamnionitis. Infants with Down syndrome were born 1-2 weeks earlier than unaffected controls.

Growth charts for weight and height of Indian children with Down syndrome

Age and gender specific growth charts for Indian children with Down syndrome (DS) based on longitudinal data have not been published. To establish percentile growth charts for DS children inhabiting northwestern parts of India, body weight and length/height of 1125 (Male: 752, Female: 373) children with DS aged <1 month to 10 years, enrolled from the "Genetics Clinic" were measured at half yearly age intervals in the "Growth Clinic" of the Institute from August 1994 to November 2018. A total of 2089 observations were made on these children using standardized anthropometric techniques and instruments following a prospective mixed-longitudinal growth research design. Using the LMS method, age and sex-specific percentile growth charts (<1 month to 10 years) for weight, and length/ height were generated. Unpaired t-test was used to compare mean growth attainments of study children with those of DS patients representing other population groups as well as their normal Multicentre Growth Reference Study (MGRS and Indian Academy of Pediatrics (IAP) counterparts. The 50th percentile growth curves for both weight and length/height of Indian children with DS demonstrated a regular increase. As compared to their normal MGRS and Indian (IAP) counterparts, the children with DS had lower weight and height attainments. The boys and girls with Down syndrome showed short stature (height < 3rd centile) from the age of 1 year till 10 years and also became underweight beyond 5 years. As compared to their normal counterparts, children with Down syndrome exhibited compromised auxological attainments. The use of growth charts presented herein may be used to compare and monitor growth and nutritional status of Indian children with Down syndrome.

Senescent hearts from male Ts65Dn mice exhibit preserved function but altered size and nicotinamide adenine dinucleotide pathway signaling

Down syndrome (DS) is associated with congenital heart defects at birth, but cardiac function has not been assessed at older ages. We used the Ts65Dn mouse, a model of DS, to quantify heart structure and function with echocardiography in 18-mo male Ts65Dn and wild-type (WT) mice. Heart weight, nicotinamide adenine dinucleotide (NAD) signaling, and mitochondrial (citrate synthase) activity were investigated, as these pathways may be implicated in the cardiac pathology of DS. The left ventricle was smaller in Ts65Dn versus WT, as well as the anterior wall thickness of the left ventricle during both diastole (LVAW_d; mm) and systole (LVAW_s; mm) as assessed by echocardiography. Other functional metrics were similar between groups including left ventricular area end systole (mm2), left ventricular area end diastole (mm2), left ventricular diameter end systole (mm), left ventricular diameter end diastole (mm), isovolumetric relaxation time (ms), mitral valve atrial peak velocity (mm/s), mitral valve early peak velocity (mm/s), ratio of atrial and early peak velocities (E/A), heart rate (beats/min), ejection fraction (%), and fractional shortening (%). Nicotinamide phosphoribosyltransferase (NAMPT) protein expression, NAD concentration, and tissue weight were lower in the left ventricle of Ts65Dn versus WT mice. Sirtuin 3 (SIRT3) protein expression and citrate synthase activity were not different between groups. Although cardiac function was generally preserved in male Ts65Dn, the altered heart size and bioenergetic disturbances may contribute to differences in aging for DS.

Epigenomic signature of major congenital heart defects in newborns with Down syndrome

BACKGROUND

Congenital heart defects (CHDs) affect approximately half of individuals with Down syndrome (DS), but the molecular reasons for incomplete penetrance are unknown. Previous studies have largely focused on identifying genetic risk factors associated with CHDs in individuals with DS, but comprehensive studies of the contribution of epigenetic marks are lacking. We aimed to identify and characterize DNA methylation differences from newborn dried blood spots (NDBS) of DS individuals with major CHDs compared to DS individuals without CHDs.

METHODS

We used the Illumina EPIC array and whole-genome bisulfite sequencing (WGBS) to quantitate DNA methylation for 86 NDBS samples from the California Biobank Program: (1) 45 DS-CHD (27 female, 18 male) and (2) 41 DS non-CHD (27 female, 14 male). We analyzed global CpG methylation and identified differentially methylated regions (DMRs) in DS-CHD versus DS non-CHD comparisons (both sex-combined and sex-stratified) corrected for sex, age of blood collection, and cell-type proportions. CHD DMRs were analyzed for enrichment in CpG and genic contexts, chromatin states, and histone modifications by genomic coordinates and for gene ontology enrichment by gene mapping. DMRs were also tested in a replication dataset and compared to methylation levels in DS versus typical development (TD) WGBS NDBS samples.

RESULTS

We found global CpG hypomethylation in DS-CHD males compared to DS non-CHD males, which was attributable to elevated levels of nucleated red blood cells and not seen in females. At a regional level, we identified 58, 341, and 3938 CHD-associated DMRs in the Sex Combined, Females Only, and Males Only groups, respectively, and used machine learning algorithms to select 19 Males Only loci that could distinguish CHD from non-CHD. DMRs in all comparisons were enriched for gene exons, CpG islands, and bivalent chromatin and mapped to genes enriched for terms related to cardiac and immune functions. Lastly, a greater percentage of CHD-associated DMRs than background regions were differentially methylated in DS versus TD samples.

CONCLUSIONS

A sex-specific signature of DNA methylation was detected in NDBS of DS-CHD compared to DS non-CHD individuals. This supports the hypothesis that epigenetics can reflect the variability of phenotypes in DS, particularly CHDs.

Utility of Screening Fetal Echocardiograms at a Single Institution Following Normal Obstetric Ultrasound in Fetuses with Down Syndrome

Fetal echocardiograms (F-echo) are recommended in all pregnancies when the fetus has Down syndrome (DS) even if there was a prior obstetric scan (OB-scan) that was normal. The utility of a screening F-echo in this high-risk population when an OB-scan is normal is unknown. Goal of this study was to evaluate if any diagnosis of a critical congenital heart disease (CHD) was missed in a fetus with DS who had a normal OB-scan. Secondary goal was to determine if any CHD was missed postnatally when an OB-scan was read as normal. Retrospective chart review of all fetuses that had a F-echo whose indication was DS between 1/1/2010 to 6/30/2022 was performed. Fetuses were included if they had an OB-scan that was read as normal and had a F-echo. Postnatal transthoracic echocardiogram (pTTE) was reviewed when available. Critical CHD was defined as CHD requiring catheterization or surgical intervention < 1 month of age. One hundred twenty-two F-echo on fetuses with DS were evaluated, of which 48 met inclusion criteria. OB-scan was performed at 20.4 ± 4.5 weeks gestational age and F-echo was performed at 24.0 ± 4.6 weeks gestational age. No patient with a normal OB-scan had a diagnosis of a critical CHD by F-echo (n = 48, negative predictive value = 100%). Evaluating those patients that had an OB-scan and a pTTE (n = 38), 14 patients were diagnosed with CHD (muscular ventricular septal defect (VSD) n = 5, perimembraneous VSD n = 3, secundum atrial septal defect (ASD) n = 2, primum ASD n = 1, transitional atrioventricular septal defect (AVSD) n = 2, and aortic valve abnormality n = 1; negative predictive value = 63.2%). F-echo correctly diagnosed 4 of the 14 missed OB-scan CHD (perimembraneous VSD n = 2, muscular VSD n = 1, and transitional AVSD n = 1). Critical CHD was not missed with a normal OB-scan in this high-risk population. F-echo also missed the majority of CHD when an OB-scan was read as normal. The cost/benefit of screening F-echo in fetuses with DS should be evaluated if a normal OB-scan has been performed, considering all these patients would have a pTTE performed per guidelines.

Two cases of placental trisomy 21 mosaicism causing false-negative NIPT results

BACKGROUND

Non-invasive prenatal testing (NIPT) using cell-free DNA has been widely used for prenatal screening to detect the common fetal aneuploidies (such as trisomy 21, 18, and 13). NIPT has been shown to be highly sensitive and specific in previous studies, but false positives (FPs) and false negatives (FNs) occur. Although the prevalence of FN NIPT results for Down syndrome is rare, the impact on families and society is significant.

CASE PRESENTATION

This article described two cases of foetuses that tested "negative" for trisomy 21 by NIPT technology using the semiconductor sequencing platform. However, the fetal karyotypes of amniotic fluid were 46,XY, + 21 der(21;21)(q10;q10) and 47,XY, + 21 karyotypes, respectively. Placental biopsies confirmed that, in the first case, the chromosome 21 placenta chimerism ratio ranged from 13 to 88% with the 46,XX, + 21,der(21;21)(q10;q10)[86]/46,XX[14] karyotype of placental chorionic cells (middle of fetal-side placental tissue). However, in the second case, of all the placental biopsies, percentage of total chimerism was less than 30%; and placental biopsies taken at the middle of maternal side and middle of fetal side, also had variable trisomy 2 mosaicism levels of 10% and 8%, respectively. Ultimately, the pregnancies were interrupted at 30 gestational age (GA) and 27GA, respectively.

CONCLUSIONS

In this study, we present two cases of FN NIPT results that might have been caused by biological mechanisms, as opposed to poor quality, technical errors, or negligence. Clinical geneticists and their patients must understand that NIPT is a screening procedure.

Epigenomic signature of major congenital heart defects in newborns with Down syndrome

Background

Congenital heart defects (CHDs) affect approximately half of individuals with Down syndrome (DS) but the molecular reasons for incomplete penetrance are unknown. Previous studies have largely focused on identifying genetic risk factors associated with CHDs in individuals with DS, but comprehensive studies of the contribution of epigenetic marks are lacking. We aimed to identify and characterize DNA methylation differences from newborn dried blood spots (NDBS) of DS individuals with major CHDs compared to DS individuals without CHDs.

Methods

We used the Illumina EPIC array and whole-genome bisulfite sequencing (WGBS) to quantitate DNA methylation for 86 NDBS samples from the California Biobank Program: 1) 45 DS-CHD (27 female, 18 male) and 2) 41 DS non-CHD (27 female, 14 male). We analyzed global CpG methylation and identified differentially methylated regions (DMRs) in DS-CHD vs DS non-CHD comparisons (both sex-combined and sex-stratified) corrected for sex, age of blood collection, and cell type proportions. CHD DMRs were analyzed for enrichment in CpG and genic contexts, chromatin states, and histone modifications by genomic coordinates and for gene ontology enrichment by gene mapping. DMRs were also tested in a replication dataset and compared to methylation levels in DS vs typical development (TD) WGBS NDBS samples.

Results

We found global CpG hypomethylation in DS-CHD males compared to DS non-CHD males, which was attributable to elevated levels of nucleated red blood cells and not seen in females. At a regional level, we identified 58, 341, and 3,938 CHD-associated DMRs in the Sex Combined, Females Only, and Males Only groups, respectively, and used machine learning algorithms to select 19 Males Only loci that could distinguish CHD from non-CHD. DMRs in all comparisons were enriched for gene exons, CpG islands, and bivalent chromatin and mapped to genes enriched for terms related to cardiac and immune functions. Lastly, a greater percentage of CHD-associated DMRs than background regions were differentially methylated in DS vs TD samples.

Conclusions

A sex-specific signature of DNA methylation was detected in NDBS of DS-CHD compared to DS non-CHD individuals. This supports the hypothesis that epigenetics can reflect the variability of phenotypes in DS, particularly CHDs.

A Trisomy 21 Lung Cell Atlas

Trisomy 21 (T21), resulting in Down Syndrome (DS), is the most prevalent chromosomal abnormality worldwide. While pulmonary disease is a major cause of morbidity and mortality in DS, the ontogeny of pulmonary complications remains poorly understood. We recently demonstrated that T21 lung anomalies, including airway branching and vascular lymphatic abnormalities, are initiated in utero. Here, we aimed to describe molecular changes at the single cell level in prenatal T21 lungs. Our results demonstrate differences in the proportion of cell populations and detail changes in gene expression at the time of initiation of histopathological abnormalities. Notably, we identify shifts in the distribution of alveolar epithelial progenitors, widespread induction of key extracellular matrix molecules in mesenchymal cells and hyper-activation of IFN signaling in endothelial cells. This single cell atlas of T21 lungs greatly expands our understanding of antecedents to pulmonary complications and should facilitate efforts to mitigate respiratory disease in DS.

Swimmers with Down Syndrome Are Healthier and Physically Fit than Their Untrained Peers

While there are positive benefits from physical activity participation for individuals with Down syndrome, little is known about the effects of swimming training. The aim of this study was to compare the body composition and physical fitness profile of competitive swimmers and moderately active (untrained) individuals with Down syndrome. The Eurofit Special test was applied to a group of competitive swimmers (n = 18) and a group of untrained individuals (n = 19), all with Down syndrome. In addition, measurements were taken to determine body composition characteristics. The results showed differences between swimmers and untrained subjects in height, sum of the four skinfolds, body fat %, fat mass index and all items of the Eurofit Special test. Swimmers with Down syndrome exhibited physical fitness levels near to the Eurofit standards, although lower fitness levels were attained by these persons when compared to athletes with intellectual disability. It can be concluded that the practice of competitive swimming seems to counteract the tendency for obesity in persons with Down syndrome and also helps to increase strength, speed and balance.

Outcomes of Posterior Spinal Fusion in Pediatric Patients with Down Syndrome

BACKGROUND

Trisomy 21 or Down syndrome is associated with multiple orthopaedic manifestations. Although cervical instability is the most common spinal condition associated with Down syndrome, the prevalence of scoliosis has been estimated at 4.8% to 8.7%. Very few prior studies have documented the role of spinal fusion in this population, and all have included ≤10 patients.

METHODS

An institutional review board-approved multicenter retrospective analysis of patients with Down syndrome treated with spinal fusion between January 2009 and December 2019 was performed by cross-referencing Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth and Tenth Revisions (ICD-9 and ICD-10) codes. Patients were followed for ≥2 years, with a mean follow-up of 3.77 years. Clinical and radiographic outcomes were collected, and complications were documented using the Clavien-Dindo-Sink (CDS) classification.

RESULTS

A total of 23 patients were included: 96% had ≥1 medical comorbidities, including 16 (70%) with congenital heart disease, of whom 88% had previous cardiac surgery, and 10 (44%) with thyroid disorders. All 23 patients underwent posterior spinal fusion. The mean estimated blood loss was 617 ± 459 mL, the mean length of the surgical procedure was 290 ± 92.7 minutes, and the mean length of hospital stay was 6.03 ± 2.91 days. The major Cobb angle measured 61.7° ± 17.6°, which corrected to 19.4° ± 14.8° (68.6% correction; p < 0.001), with well-maintained correction at 2 years of 22.0° ± 10.3° (64.3% correction; p = 0.158). Thirteen (57%) of 23 patients had a change in curve of >5°. There were no intraoperative complications; however, 12 patients (52%) sustained postoperative complications (e.g., need for reoperation, implant failure, and pulmonary complications), including 6 patients with CDS type 3 or 4 (e.g., wound dehiscence, late superficial abscess, pleural effusion, pseudarthrosis, and readmission for hypoxia). Four patients (17%) required a revision surgical procedure. One patient (4%) required an unplanned intensive care unit admission.

CONCLUSIONS

Although instrumented spinal fusion can effectively correct spinal deformity in these patients, complications are more frequent than in children with adolescent idiopathic scoliosis, with over half of patients sustaining a complication.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Impact of fetal trisomy 21 on umbilical artery Doppler indices

OBJECTIVES

Umbilical artery (UA) Doppler indices are surrogate measures of placental function, most commonly used to assess fetal wellbeing in pregnancies with fetal growth restriction. Fetuses with trisomy 21 (t21) are reported to have elevated UA Doppler indices, but reference percentiles are currently lacking for this population. We hypothesized that gestational age-specific values of UA Doppler indices in pregnancies complicated by t21 will be elevated compared to established percentiles based on euploid pregnancies. We aimed to assess UA Doppler indices longitudinally in fetuses with t21 in order to demonstrate Doppler patterns across gestation in this population, compare them with euploid fetuses, and investigate their association with pregnancy outcomes.

METHODS

We conducted a retrospective cohort study of singleton pregnancies with confirmed fetal t21 who underwent UA Doppler surveillance antenatally from January 2012 to August 2019. UA Doppler indices, including systolic/diastolic (S/D) ratio, pulsatility index (PI), and resistance index (RI) were extracted from ultrasound reports or directly from ultrasound images. UA S/D, PI, and RI percentiles by gestational week were created from available observations from our cohort via a data-driven approach using a generalized additive model. A secondary analysis was run to statistically compare t21 values to established percentiles based on observations from a historical population of euploid fetuses.

RESULTS

UA Doppler measurements from 86 t21 fetuses and 130 euploid fetuses were included in our analysis. Median (IQR) maternal age in t21 pregnancies and euploid pregnancies were 35 years (29-38) and 30 years (27-33), respectively. As in euploid fetuses, we found a negative association between Doppler indices and gestational age in the t21 fetuses. Maternal tobacco use, obesity, or chronic hypertension had no significant effect on UA Doppler indices. As hypothesized, values for UA S/D ratio, PI, and RI at the 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97.5th percentiles by gestational week were significantly higher in t21 fetuses compared to euploid fetuses (p<.001). Overall, 55.8% (48/86) of the t21 fetuses demonstrated at least one Doppler value above the 95th percentile for gestational age based on euploid reference standard. At birth, eight (9.3%) of the t21 fetuses were small for gestational age. When these pregnancies were removed from analysis, UA Doppler indices remained significantly higher than established percentiles at each week of gestation (p < .001). Only three pregnancies ended in fetal demise in the t21 population, two of which had persistently elevated Dopplers above the 95th percentile per established reference percentiles.

CONCLUSIONS

At each week of gestation, UA Doppler indices in t21 fetuses were significantly higher than established percentiles from a euploid population. Reference intervals based on euploid fetuses may therefore not be appropriate for antenatal surveillance of fetuses with t21. Prospective studies are needed to investigate the role and impact of serial UA Doppler velocimetry in the surveillance of pregnancies complicated by fetal t21.

Sex Differences in Protein Expression and Their Perturbations in Amniotic Fluid Cells of Down Syndrome Fetuses

Down syndrome (DS) is the most common chromosomal condition associated with intellectual disability and is characterized by a variety of additional clinical findings. The pathogenesis of DS and the differences between the sexes are not clear. In order to identify differentially expressed proteins that might be employed as potential biological markers and elucidate the difference in pathogenesis between different genders of T21 fetuses, providing clues for individualized detection and treatment is essential. Amniocyte samples of T21 males, T21 females, CN males, and CN females were collected by amniocentesis. The quantitative value of the peptide corresponding to each sample was determined through quantitative analysis by mass spectrometry. We identified many differentially expressed proteins between T21 fetuses and CN fetuses/T21 males and CN males/T21 females and CN females/and T21 males and T21 females. These differential proteins are associated with many important biological processes and affect the development of multiple systems, including the heart, hematopoietic, immune, reproductive, and nervous systems. Our results show sex-specific modulation of protein expression and biological processes and provide new insights into sex-specific differences in the pathogenesis of DS.

Cardiac Structure and Function in Adults with Down Syndrome

Various factors may alter the risk for cardiovascular disease in adults with Down syndrome (Ds), yet few studies have examined differences in cardiac physiology in this population. Previous research suggested lower systolic and diastolic function, but inconsistent methodologies and younger samples warrant research in adults with Ds. Our aim is to compare the cardiac structure and function of adults with Ds to age- and sex-matched adults without Ds. Echocardiography was used to assess systolic function, diastolic function, and cardiac structure in n = 19 adults (Ds n = 9, control n = 10). Regarding cardiac structure, adults with Ds had increased left ventricular posterior wall thickness at end-systole compared to adults without Ds (p = 0.007). Regarding systolic and diastolic function, adults with Ds were found to have lower septal peak systolic annular velocity (S') (p = 0.026), lower lateral and septal mitral annular early diastolic velocity (E') (p = 0.007 and p = 0.025, respectively), lower lateral peak mitral annular late diastolic velocity (A') (p = 0.027), and higher lateral and septal mitral annular early systolic velocity to diastolic velocity ratios (E/e') (p = 0.001 and p = 0.001, respectively). Differences in both cardiac structure and function were found when comparing adults with Ds to matched adults without Ds. Most of the differences were indicative of worse diastolic function.

Laryngeal pathologies in dysphonic children with Down Syndrome

INTRODUCTION

Down syndrome is the most common chromosomal abnormality and is associated with a higher incidence of congenital heart defects, which often require surgery within the first year of life. Previous studies have found that children with Down syndrome are at higher risk for subglottic stenosis, vocal fold paralysis, and laryngomalacia. The goal of this study is to review children with Down syndrome presenting with dysphonia and to characterize their laryngeal pathologies.

METHODS

A retrospective review was performed of patients with Down syndrome seen at a tertiary pediatric hospital's department of otolaryngology from Jan. 2007-Jul. 2021 for voice-related concerns. Inclusion criteria included age less than 18 years, diagnosis of Trisomy 21, and complaint of dysphonia. The data extracted included history of dysphonia, co-morbidities, demographic information, age at presentation, perceptual voice assessments, voice quality of life scores, acoustic data, laryngoscopic and/or videostroboscopic exams, and surgical procedures.

RESULTS

Twenty-three total patients met the study criteria. Of these children, 13 (57%) were male and 10 (43%) were female. The mean age at first presentation was 4.08 years (range 12 days-16.3 years). Eleven of the 23 patients presented within the first 12 months of life. Sixteen patients were diagnosed with vocal fold immobility, 13 of which were left-sided unilateral immobility and the remaining 3 were bilateral immobility. 5 patients were diagnosed with vocal fold nodules. 12 children in the immobility group had a history of cardiothoracic surgery at our institution. Only 3 patients had Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) assessments, though all three showed overall dysphonia ratings of severely deviant, with roughness and strain scores being the most severe.

DISCUSSION

The most common etiology of dysphonia in our Down syndrome patient population was vocal fold immobility and hypomobility, as opposed to vocal fold nodules (which is the most common in the general pediatric population). The higher likelihood of cardiac surgery in patients with Trisomy 21 may result in the increased incidence of vocal fold immobility. There should be a low threshold to refer dysphonic patients with Down syndrome for laryngoscopic evaluation, as treatment options may be available.

Heart Transplantation in Children With Down Syndrome

Background

Children with Down syndrome (DS) have a high risk of cardiac disease that may prompt consideration for heart transplantation (HTx). However, transplantation in patients with DS is rarely reported. This project aimed to collect and describe waitlist and post– HTx outcomes in children with DS.

Methods and Results

This is a retrospective case series of children with DS listed for HTx. Pediatric HTx centers were identified by their participation in 2 international registries with centers reporting HTx in a patient with DS providing detailed demographic, medical, surgical, and posttransplant outcome data for analysis. A total of 26 patients with DS were listed for HTx from 1992 to 2020 (median age, 8.5 years; 46% male). High‐risk or failed repair of congenital heart disease was the most common indication for transplant (N=18, 69%). A total of 23 (88%) patients survived to transplant. All transplanted patients survived to hospital discharge with a median posttransplant length of stay of 22 days. At a median posttransplant follow‐up of 2.8 years, 20 (87%) patients were alive, 2 (9%) developed posttransplant lymphoproliferative disorder, and 8 (35%) were hospitalized for infection within the first year. Waitlist and posttransplant outcomes were similar in patients with and without DS (P=non‐significant for all).

Conclusions

Waitlist and post‐HTx outcomes in children with DS selected for transplant listing are comparable to pediatric HTx recipients overall. Given acceptable outcomes, the presence of DS alone should not be considered an absolute contraindication to HTx.

What are the Soft Tissue Risk Factors for Obstructive Sleep Apnea in Patients with Down's Syndrome?

OBJECTIVE

To determine the risk factors and their respective magnitudes for developing Obstructive Sleep Apnea (OSA) in Down syndrome (DS) patients.

DESIGN

Retrospective cohort study.

PATIENTS

The 2016 Kids' Inpatient Database (KID) was queried to identify all patients diagnosed with DS.

MAIN OUTCOME MEASURES

The primary predictor variables were tonsillar hypertrophy (TH), adenoidal hypertrophy (AH), Hypertrophy of Tonsils & Adenoids (HTA), Laryngeal Stenosis (LS), Hypotonia, Glossoptosis, Congenital Laryngomalacia (CL), and Overweight & Obesity (OO). The primary outcome variable was OSA.

RESULTS

The final sample consisted of 18,181 patients with a diagnosis of DS. Relative to patients aged 0-5, patients aged 6-10 (OR 3.5, P < 0.01), 11-5 (OR 3.4, P < 0.01), and 16 & above (OR 3.6, P < 0.01) were each independently associated with increased odds of OSA. Further, TH (OR 23.2, P < 0.01), AH (OR 20.3, P < 0.01), HTA (OR 64.2, P < 0.01), glossoptosis (OR 5.0, P < 0.01), CL (OR 4.3, P < 0.01), and OO (OR 3.7, P < 0.01) were all independent risk factors for OSA.

CONCLUSIONS

The presence of hypertrophied tonsils and adenoids together was the strongest risk factor for OSA. DS patients aged six and above were at risk for OSA development relative to younger patients. Patients with DS should be tested for OSA, which otherwise will deteriorate their existing comorbidities.

Hospital admissions in infants with Down syndrome: a record-linked population-based cohort study in Wales

BACKGROUND

Despite recent advances, mortality in children with Down syndrome remains five times higher than in the general population. This study aims to describe the burden, patterns and causes of hospital admissions in infants with Down syndrome, and compare this with infants without Down syndrome in a population-based cohort.

METHODS

This study used data from the Wales Electronic Cohort for Children, a cohort of all children born in Wales between 1990 and 2012. The cohort was generated from routine administrative data, linked to create an anonymised data set within the Secure Anonymised Information Linkage databank. This analysis is based on all infants born between January 2003 and January 2012 who were followed to their first birthday, a move out of Wales, death, or until 31 October 2012 (end of follow-up). Infants with Down syndrome were identified using the Congenital Anomaly Register and Information Service in Wales. Multivariable Cox regression was used to compare the time to first hospital admission. Admission codes were used to identify the commonest indications for hospitalisation and to determine the presence of other congenital anomalies.

RESULTS

We included 324 060 children, 356 of whom had Down syndrome. Of infants with Down syndrome, 80.3% had at least one hospital inpatient admission during the first year of life, compared with 32.9% of infants without Down syndrome. These first admissions were earlier [median of 6 days interquartile range (IQR) (3, 72) compared with 45 days [IQR 6, 166)] and longer [median of 4 days (IQR 1, 15) compared with 1 day (IQR 0, 3)] than in infants without Down syndrome. The most common causes of admissions were congenital abnormalities, respiratory diseases, conditions originating in the perinatal period and infectious diseases. The presence of other congenital abnormalities increased hospitalisations in all infants, but more so in infants with Down syndrome who spent a median of 21 days in hospital (IQR 11, 47) during their first year of life.

CONCLUSION

Infants with Down syndrome are at high risk for early, more frequent and longer hospital admissions. Congenital heart disease and respiratory infections remain a major burden in this population. More research is needed to understand how to better manage these conditions particularly in the first month of life when most admissions occur.

Down syndrome and breastfeeding: A systematic review

Several conditions related to serious difficulty in initiating and maintaining breastfeeding in neonates with Down syndrome are described in the literature. This study aimed to investigate the frequency of breastfeeding in neonates with Down syndrome, as well as the reasons for not breastfeeding, through a systematic literature review by searching MEDLINE via PubMed, Cochrane Library, Scopus, Embase via Elsevier, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases. Sixteen studies were included with a total sample size of 2022 children with Down syndrome. The frequency of exclusive breastfeeding was 31.6-55.4%, with five studies reporting breastfeeding for longer than 6 months. Breastfeeding from birth was present for 48-92.5% of the children with Down syndrome in six studies. Two studies reported that around 50% and 23.3% of the children with Down syndrome were never breastfed, and rates of breastfeeding in infants with Down syndrome were lower than those in controls in three studies. The reasons for not breastfeeding or cessation of breastfeeding were associated with Down syndrome-specific challenges, maternal reasons, and healthcare aspects.

Effects of vitamin D supplementation and aerobic exercises on balance and physical performance in children with Down syndrome

Background/Aims

Children with Down syndrome are prone to vitamin D deficiency. Vitamin D supplements are commonly used to treat and prevent vitamin D deficiencies. There is growing evidence that support the role of vitamin D improving muscles and central nervous system function. The aim of this study was to investigate the interaction effects of vitamin D supplementation combined with aerobic exercises and conventional physical therapy on balance and physical performance in children with Down syndrome.

Methods

A randomised controlled trial was conducted for 38 children with Down syndrome, with ages ranging from 8 to 12 years. They were divided randomly into two groups. The control group (n=19) received conventional physical therapy and aerobic exercises, while the study group (n=19) received conventional physical therapy, aerobic exercises and vitamin D in the form of an oral daily dose of vitamin D3 400 IU (cholecalciferol). The children in both groups participated in the same physical therapy for 45 minutes, 3 days a week for 12 weeks, and undertook 15 minutes of aerobic exercise after the physical therapy sessions. Balance was evaluated by using the Biodex Stability System and physical performance was evaluated by using the 6-Minute Walk Test.

Results

All groups showed a significant improvement in the medial-lateral stability index, the anterior-posterior stability index, the overall stability index and the 6-Minute Walk Test after treatment (P<0.05). The study group showed a significant improvement in the measured variables compared with that of the control group (P<0.05).

Conclusions

Vitamin D supplements, combined with aerobic exercises and conventional physical therapy, could improve balance and physical performance in children with Down syndrome. Therefore, vitamin D and aerobic exercises should be considered as an adjunctive to physical therapy.

Effect of Application of Different Exercise Intensities on Vitamin D and Parathormone in Children with Down's Syndrome

BACKGROUND

Children with Down's syndrome are more liable to vitamin D deficiency. Treating this deficiency with supplements is associated with the risk of intoxication.

AIM

The study is aimed at comparing the effect of two exercise intensities on the modulation of vitamin D and parathormone levels in children with DS.

METHODS

Forty-four DS male children aged from 8 to 12 years participated in the study. They were assigned randomly into two equal groups. Group I received high-intensity treadmill aerobic exercises, and group II received moderate-intensity T-AE, three times per week for three months. The blood samples were collected from both groups before the intervention, after one month of intervention, then after three months of intervention to assess serum 25(OH)D and PTH levels.

RESULTS

Repeated measure MANOVA revealed that the high-intensity T-AE induced a significant increase in 25(OH)D after one month and after three months while it significantly decreased PTH only after three months. Moderate-intensity T-AE had a nonsignificant effect on both hormones.

CONCLUSION

The current study concluded that the high-intensity T-AE improved both vitamin D and parathormone serum levels after three months of intervention.

Can I breastfeed my baby with Down syndrome? A scoping review

AIM

To summarise existing evidence about barriers and enablers to breastfeeding babies with Down syndrome (DS) in peer-reviewed literature.

METHODS

Ovid Medline, CINAHL, Scopus and Ovid Emcare were searched. Inclusion and exclusion criteria were used to screen yielded articles and those meeting the criteria were included for data extraction. Two authors extracted data including outcomes, design, definition of DS, barriers and enablers to breastfeeding babies with DS.

RESULTS

Sixteen studies met the inclusion and exclusion criteria. Barriers and enablers were categorised into maternal, child and health professional factors.

CONCLUSIONS

This review identified a significant literature gap related to breastfeeding babies with DS and more definitive research under current standards is needed. Mothers reported the need for high-quality health professional breastfeeding support and evidence-based effective breastfeeding techniques. A collaborated and concerted approach from both mothers and health professionals is important to optimise breastfeeding for babies with DS.

Lung disease manifestations in Down syndrome

Down syndrome (DS) is one of the most prevalent chromosomal abnormalities worldwide, affecting 1 in 700 live births. Although multiple organ systems are affected by the chromosomal defects, respiratory failure and lung disease are the leading causes of morbidity and mortality observed in DS. Manifestations of DS in the respiratory system encompass the entire lung starting from the nasopharynx to the trachea/upper airways to the lower airways and alveolar spaces, as well as vascular and lymphatic defects. Most of our knowledge on respiratory illness in persons with DS arises from pediatric studies; however, many of these disorders present early in infancy, supporting developmental mechanisms. In this review, we will focus on the different lung phenotypes in DS, as well as the genetic and molecular pathways that may be contributing to these complications during development.

Gain in growth after surgical repair of congenital heart disease among children with Down syndrome

Down syndrome (DS) is a common genetic disorder among Saudi children, for which limited data is available on growth for those who undergo surgery for congenital heart disease (CHD). We assessed the magnitude of growth over time following surgery and the factors associated with growth change. Eighty-eight children with DS and CHD who underwent surgery between 2009 and 2017 at the tertiary children's hospital in Al-Qassim, Saudi Arabia, were eligible. Information on gender, height, and weight (at surgery, 6 and 12 months), age at surgery, and type of CHD were abstracted from the medical records. Repeated measure analysis of variance (ANOVA) was used for data analysis. The sample's mean age (SD) was 16.2 months (20.1); 47% were male. Height, weight, and body mass index (BMI) increased significantly at both follow-up points. There was a significant interaction between age at surgery, type of heart disease, and time for all three physical indices (p-values <0.001). The increase in height, weight, and BMI was significantly greater for children ≤8 months old with acyanotic CHD compared to children >8 months with cyanotic CHD. Overall, the gain in growth was greater for the children with DS who had had surgery at a younger age.

The Effects of Different Exteroceptive Experiences on the Early Motor Repertoire in Infants With Down Syndrome

OBJECTIVE

Down syndrome is a chromosomal abnormality in which muscle tone, motor development, and sensory systems are affected. The objectives of this study were to examine the changes in movements and postures of 3- to 5-month-old infants with Down syndrome and infants who were neurotypical controls during exposure to a rough-textured surface and to compare the differences occurring before and during an exteroceptive condition that was different between the 2 groups.

METHODS

In this quasi-experimental study, participants were 20 infants with Down syndrome (8 female infants; age range = 10-18 weeks, mean [SD] = 12 weeks 2 days [2 weeks 2 days]) and 20 age-matched infants with typical development (8 female infants; age range = 9-17 weeks, mean (SD) = 12 weeks 6 days [1 week 5 days]). The movements and postures of the infants, including fidgety movements, were assessed according to the General Movements Assessment, which determines the Motor Optimality Score (MOS), on 2 surfaces.

RESULTS

The MOS outcomes of the infants with Down syndrome (median = 21.5, range = 6-28) were significantly lower than those of the infants who were neurotypical (median = 28, range = 23-28) on a standard mattress. The postures were found to be significantly better in infants with Down syndrome during exposure to a rough-textured surface. The MOS did not change due to the different exteroceptive experiences in infants with Down syndrome and infants who were neurotypical.

CONCLUSION

The different exteroceptive experiences caused only postural alterations, which might play a crucial role in early intervention programs for infants with Down syndrome.

IMPACT

This is the first study, to our knowledge, on the effects of different exteroceptive conditions, such as a coco coir mattress covered with muslin fabric, on the early motor repertoire in infants with Down syndrome. The findings showed that infants with Down syndrome had heterogeneity in their fidgety movements and large variability of the MOS, and the MOS results from infants with Down syndrome were lower than those of infants who were neurotypical. Fidgety movements and the MOS did not change due to the different exteroceptive experiences in either group. Significant improvements in posture were observed during exposure to a rough-textured surface. The improvement of posture is essential; clinicians might consider the positive effect of putting an infant with Down syndrome on a rough-textured surface and include this strategy in early intervention programs.

Neuro-Ophthalmological Manifestations in Children with Down Syndrome: Current Perspectives

Down syndrome, caused by an extra copy of all or part of chromosome 21, is the most prevalent intellectual disability of genetic origin. Among numerous comorbidities which are part of the phenotype of individuals with Down syndrome, ocular problems appear to be highly prevalent. Neuro-ophthalmological manifestations, such as ocular alignment and motility disturbances, amblyopia, hypoaccommodation or optic nerve abnormalities, and other organic ocular anomalies frequently reported in Down syndrome, may lead to an overall decrease in visual acuity. Although numerous studies have reported ocular anomalies related to Down syndrome, it remains challenging to determine the impact of each anomaly upon the decreased visual acuity, as most such individuals have more than one ocular problem. Even in children with Down syndrome and no apparent ocular defect, visual acuity has been found to be reduced compared with typically developing children. Pediatric ophthalmological examination is a critical component of a multidisciplinary approach to prevent and treat ocular complications and improve the visual outcome in children with Down syndrome. This narrative review aims to provide a better understanding of the neuro-ophthalmological manifestations and discuss the current ophthalmological management in children with Down syndrome.

Down syndrome and congenital heart disease: perioperative planning and management

Approximately 50% of newborns with Down syndrome have congenital heart disease. Non-cardiac comorbidities may also be present. Many of the principles and strategies of perioperative evaluation and management for patients with congenital heart disease apply to those with Down syndrome. Nevertheless, careful planning for cardiac surgery is required, evaluating for both cardiac and noncardiac disease, with careful consideration of the risk for pulmonary hypertension. In this manuscript, for children with Down syndrome and hemodynamically significant congenital heart disease, we will summarize the epidemiology of heart defects that warrant intervention. We will review perioperative planning for this unique population, including anesthetic considerations, common postoperative issues, nutritional strategies, and discharge planning. Special considerations for single ventricle palliation and heart transplantation evaluation will also be discussed. Overall, the risk of mortality with cardiac surgery in pediatric patients with Down syndrome is no more than the general population, except for those with functional single ventricle heart defects. Underlying comorbidities may contribute to postoperative complications and increased length of stay. A strong understanding of cardiac and non-cardiac considerations in children with Down syndrome will help clinicians optimize perioperative care and long-term outcomes.

Percentile Charts for Body Mass Index of Indian Down Syndrome Children

Growth charts are used to detect growth impairment, overweight, and obesity among Down syndrome (DS) children belonging to different population groups. Due to nonavailability of similar information, age, and gender specific body mass index (BMI) charts for DS children of Indian origin, based on serial data, have been developed. A total of 752 boys and 373 girls diagnosed as cases of DS at <1 month to 10 years of age enrolled from the “genetic clinic” were followed up in the “growth clinic/growth laboratory” of the institute, following a mixed-longitudinal growth research design. BMI was calculated from body weight and length/height measured at 6-month-age intervals by using standardized techniques and instruments. Age and sex-specific percentile growth charts for BMI were generated for age range <1 month to 10 years by using the LMS method. DS children remained wasted (BMI <3rd percentile) up to 6 months of age; thereafter, BMI increased to exhibit close similarity with their normal Multicentre Growth Reference Study (World Health Organization 2006) and Indian Academy of Pediatrics (2015) counterparts up to 5 to 10 years, respectively. The percentage of obese DS girls (8.76%) outnumbered boys with DS (4.1%). The use of age and gender specific BMI growth charts may be made for comparative purpose, to assess nutritional status of Indian children with DS, to initiate suitable need-based intervention to improve their overall health and for timely institution of target interventions to prevent growth faltering in this vulnerable population.

Longer Exposure to Left-to-Right Shunts Is a Risk Factor for Pulmonary Vein Stenosis in Patients with Trisomy 21

We conducted a study to determine whether patients born with Trisomy 21 and left-to-right shunts who develop pulmonary vein stenosis (PVS) have a longer exposure to shunt physiology compared to those who do not develop PVS. We included patients seen at Boston Children’s Hospital between 15 August 2006 and 31 August 2017 born with Trisomy 21 and left-to-right shunts who developed PVS within 24 months of age. We conducted a retrospective 3:1 matched case–control study. The primary predictor was length of exposure to shunt as defined as date of birth to the first echocardiogram showing mild or no shunt. Case patients with PVS were more likely to have a longer exposure to shunt than patients in the control group (6 vs. 3 months, p-value 0.002). Additionally, PVS patients were also more likely to have their initial repair ≥ 4 months of age (81% vs. 42%, p-value 0.003) and have a gestational age ≤ 35 weeks (48% vs. 13%, p-value 0.003). Time exposed to shunts may be an important modifiable risk factor for PVS in patients with Trisomy 21.

Proteomics Study of Peripheral Blood Mononuclear Cells in Down Syndrome Children

Down syndrome (DS) is the most common chromosomal disorder and the leading genetic cause of intellectual disability in humans, which results from the triplication of chromosome 21. To search for biomarkers for the early detection and exploration of the disease mechanisms, here, we investigated the protein expression signature of peripheral blood mononuclear cells (PBMCs) in DS children compared with healthy donors (HD) by using an in-depth label-free shotgun proteomics approach. Identified proteins are found associated with metabolic pathways, cellular trafficking, DNA structure, stress response, cytoskeleton network, and signaling pathways. The results showed that a well-defined number of dysregulated pathways retain a prominent role in mediating DS pathological features. Further, proteomics results are consistent with published study in DS and provide evidences that increased oxidative stress and the increased induction of stress related response, is a participant in DS pathology. In addition, the expression levels of some key proteins have been validated by Western blot analysis while protein carbonylation, as marker of protein oxidation, was investigated. The results of this study propose that PBMCs from DS children might be in an activated state where endoplasmic reticulum stress and increased production of radical species are one of the primary events contributing to multiple DS pathological features.

Pulmonary hypertension and myocardial function in infants and children with Down syndrome

Down Syndrome (DS) is the most common chromosomal abnormality of live born babies. Individuals with DS are at increased risk of cardiopulmonary morbidities in the early neonatal period, infancy and childhood that manifest with elevated pulmonary arterial pressures and altered myocardial performance. Pulmonary hypertension (PH) during the early neonatal period remains under-recognised in this population. PH may occur with or without a congenital heart defect in children with DS and is more common than in the general population. Early detection and continued screening of PH throughout infancy and childhood for these at-risk children is crucial for prompt intervention and potential prevention of long-term sequelae on cardiac function. This review summarises the main physiological concepts behind the mechanisms of PH in children with DS and provides a summary of the current available literature on PH and its impact on myocardial performance.

Chromosomal abnormalities and atrial fibrillation and ischemic stroke incidence: a nationwide population-based study

There is a paucity of information as to whether chromosomal abnormalities, including Down Syndrome, Turner Syndrome, and Klinefelter Syndrome, have an association with atrial fibrillation (AF) and ischemic stroke development. Data from 3660 patients with Down Syndrome, 2408 with Turner Syndrome, and 851 with Klinefelter Syndrome without a history of AF and ischemic stroke were collected from the Korean National Health Insurance Service (2007–2014). These patients were followed-up for new-onset AF and ischemic stroke. Age- and sex-matched control subjects (at a ratio of 1:10) were selected and compared with the patients with chromosomal abnormalities. Down Syndrome patients showed a higher incidence of AF and ischemic stroke than controls. Turner Syndrome and Klinefelter Syndrome patients showed a higher incidence of AF than did the control group, but not of stroke. Multivariate Cox regression analysis revealed that three chromosomal abnormalities were independent risk factors for AF, and Down Syndrome was independently associated with the risk of stroke. In conclusion, Down Syndrome, Turner Syndrome, and Klinefelter Syndrome showed an increased risk of AF. Down Syndrome patients only showed an increased risk of stroke. Therefore, AF surveillance and active stroke prevention would be beneficial in patients with these chromosomal abnormalities.

Isolated echogenic intracardiac foci and the role of cell-free fetal DNA: A cost-effectiveness analysis

OBJECTIVES

Cell-free fetal DNA (cfDNA) has been increasingly incorporated into prenatal aneuploidy screening paradigms given its relatively high sensitivity for Down syndrome (DS). This is often the case when fetal ultrasonographic soft markers are present, such as the relatively common echogenic intracardiac focus (EIF). We sought to evaluate the cost-effectiveness of a screening strategy that included cfDNA screening when an isolated EIF is identified in a low-risk population with prior aneuploidy screening.

METHODS

A decision-analytic model was constructed using TreeAge software with probabilities derived from the literature. Our model compared cfDNA screening following isolated EIF detection in women less than 35 years with prior reassuring first trimester screen compared to a strategy of no further aneuploidy screening. Strategies were compared to generate an incremental cost-effectiveness ratio with a threshold of $100 000/quality-adjusted life year (QALY) and applied to a theoretical cohort.

RESULTS

The cfDNA strategy resulted in 21 fewer DS births and 52 additional QALYs, however, increased costs by $51.3 million. This yielded an incremental cost-effectiveness ratio of $986 503; therefore, it was not a cost-effective strategy.

CONCLUSION

In a low-risk population with prior reassuring aneuploidy screening, it is not cost effective to offer cfDNA after identification of an isolated EIF.

An Analysis of Hospital Mortality After Cardiac Operations in Children With Down Syndrome

Children with Down syndrome (DS) have lower mortality compared to nonsyndromic (NS) children after atrioventricular septal defect (AVSD) repair. Limited data exist regarding hospital mortality and utilization after other congenital heart disease (CHD) operations in DS. We compared hospital mortality and utilization after CHD operations in both populations and hypothesized that the survival benefit in children with DS is not consistent across CHD lesions. The Texas Inpatient Public Use Datafile was queried for all patients <18 years old undergoing operations for CHD between 1999 and 2016. Hospital mortality, length-of-stay and charges were compared between DS and NS groups, stratified by CHD operation using mixed-effects multivariable analyses and propensity score matching analyses adjusting for prematurity, low birth weight, age, and sex. Over the 18-year period, 2841 cases with DS underwent CHD operations compared to 25,063 NS cases. The most common types of interventions performed in DS were AVSD repair, isolated ventricular septal defect (VSD) repair and tetralogy of Fallot (TOF) repair. By multivariable analyses, DS was associated with lower mortality after isolated AVSD repair (RR 0.40 [IQR 0.20-0.79]), and higher hospital mortality after bidirectional Glenn anastomosis (BDG) (RR 5.17 [IQR 2.10-12.77]) and TOF/pulmonary atresia repair (RR 9.71 [IQR 2.16-43.68]) compared to NS children. Similar results were noted using propensity score matching. Children with DS had lower mortality after AVSD repair than NS children, but higher mortality after operations for BDG and TOF/pulmonary atresia. Further study is needed to determine if the presence of pulmonary hypertension in DS modifies the association between DS and mortality depending on cardiac lesion.

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.

Differences in morbidity and mortality in Down syndrome are related to the type of congenital heart defect

Morbidity and mortality in Down syndrome (DS) are mainly related to congenital heart defects (CHDs). While CHDs with high prevalence in DS (typical CHDs), such as endocardial cushion defects, have been extensively described, little is known about the impact of less common CHDs (atypical CHDs), such as aortic coarctation and univentricular hearts. In our single-center study, we analyzed, in observational, retrospective manner, data regarding cardiac features, surgical management, and outcomes of a cohort of DS patients. Literature review was performed to investigate previously reported studies on atypical CHDs in DS. Patients with CHDs were subclassified as having typical or atypical CHDs. Statistical analysis was performed for comparison between the groups. The study population encompassed 859 DS patients, 72.2% with CHDs, of which 4.7% were atypical. Statistical analysis showed a significant excess in multiple surgeries, all-cause mortality and cardiac mortality in patients with atypical CHDs (p = .0067, p = .0038, p = .0001, respectively). According to the Kaplan-Meier method, survival at 10 and 40 years was significantly higher in typical CHDs (99 and 98% vs. 91 and 84%, log rank <0.05). Among atypical CHDs, it seems that particularly multiple complex defects in univentricular physiology associate with a worse outcome. This may be due to the surgical difficulty in managing univentricular hearts with multiple defects concurring to the clinical picture or to the severity of associated defects themselves. Further studies need to address this specific issue, also considering the higher pulmonary pressures, infective complications, and potential comorbidities in DS patients.

Effects of Pidotimod on recurrent respiratory infections in children with Down syndrome: a retrospective Italian study

BACKGROUND

Children with Down syndrome (DS) show a high susceptibility to recurrent infections (RI), caused by immune defects and abnormalities of the airways. Our goal was to investigate the effects of Pidotimod on RI prevention in children with DS, comparing immune and clinical parameters before (T0) and after (T1) the treatment with Pidotimod.

METHODS

The study was conducted at the Down syndrome outpatient Center of Bambino Gesù Children's Hospital, in Rome. We reviewed the medical records of all children with a positive history for RI and who received oral prophylaxis of Pidotimod from September 2016 to February 2017.

RESULTS

Thirty-three children met the inclusion criteria (males: 51.5%; average age: 6 years ±SD: 3). We found a significant decrease in the number of children with upper respiratory infections (82% at T0 vs 24% at T1; p = 0,0001) and with lower respiratory infections (36% at T0 vs 9% at T1; p = 0.003) after treatment with Pidotimod. We also demonstrated a significant decrease in the number of children hospitalized for respiratory infections (18% at T0 vs 3% at T1; p = 0.03). We measured T and B cells in the peripheral blood and B cell function in vitro at T0 and T1. We found that the response to CpG improved at T1. A significant increase of B cell frequency (p = 0.0009), B cell proliferation (p = 0.0278) and IgM secretion (p = 0.0478) were observed in children with DS after treatment.

CONCLUSIONS

Our results provided evidence that Pidotimod may be able to prevent RI in children with Down syndrome.

Mortality Among Children with Down syndrome in Hong Kong: A Population-Based Cohort Study from Birth

OBJECTIVES

To describe the mortality patterns, comorbidities, and attendance at accident and emergency departments among children with Down syndrome in Hong Kong.

STUDY DESIGN

This is a population-based, retrospective cohort study of live births of children with Down syndrome delivered between 1995 and 2014, as identified from territory-wide hospitalization data in Hong Kong. The Kaplan-Meier product limit method was adopted to estimate the survival probabilities of children with Down syndrome by selected demographic and clinical characteristics. Cox regression analyses were conducted to examine associations of comorbidities and accident and emergency department accident and emergency departments attendances with mortality patterns.

RESULTS

There were 1010 live births of children with Down syndrome in Hong Kong within the study period and the average rate of live births with Down syndrome was 8.0 per 10 000 live births (95% CI, 6.8-9.30). The rate of live births with Down syndrome over the past 2 decades decreased from 11.8 per 10 000 live births in 1995 to 3.4 per 10 000 in 2014. Eighty-three patients with Down syndrome died during this period. The overall 6-month and 1- and 5-year survival probabilities were 95.8%, 94.4%, and 92.6%, respectively. There was a significant decrease in mortality rates over the study period, particularly among those born between 2000-2004 and 2005-2009 compared with those born between 1995 and 1999 (P < .05). Patients with Down syndrome without congenital cardiovascular anomalies and without low birth weight had lower mortality rates than those with these diagnoses.

CONCLUSIONS

Over the past 2 decades, the early life mortality of children with Down syndrome in Hong Kong has improved significantly along with a reduction in Down syndrome live births.

Down Syndrome Reduces the Sedative Effect of Midazolam in Pediatric Cardiovascular Surgical Patients

Down syndrome (DS) is frequently comorbid with congenital heart disease and has recently been shown to reduce the sedative effect of benzodiazepine (BDZ)-class anesthesia but this effect in a clinical setting has not been studied. Therefore, this study compared midazolam sedation after heart surgery in DS and normal children. We retrospectively reviewed patient records in our pediatric intensive care unit (PICU) of pediatric cardiovascular operations between March 2015 and March 2018. We selected five days of continuous post-operative data just after termination of muscle relaxants. Midazolam sedation was estimated by Bayesian inference for generalized linear mixed models. We enrolled 104 patients (average age 26 weeks) of which 16 (15%) had DS. DS patients had a high probability of receiving a higher midazolam dosage and dexmedetomidine dosage over the study period (probability = 0.99, probability = 0.97) while depth of sedation was not different in DS patients (probability = 0.35). Multi regression modeling included severity scores and demographic data showed DS decreases midazolam sedation compared with controls (posterior OR = 1.32, 95% CrI = 1.01-1.75). In conclusion, midazolam dosages should be carefully adjusted as DS significantly decreases midazolam sedative effect in pediatric heart surgery patients.

Diversity and dysmorphology

PURPOSE OF REVIEW

Dysmorphic features result from errors in morphogenesis frequently associated with genetic syndromes. Recognizing patterns of dysmorphic features is a critical step in the diagnosis and management of human congenital anomalies and genetic syndromes. This review presents recent developments in genetic syndromes and their related dysmorphology in diverse populations.

RECENT FINDINGS

Clinical findings in patients with genetic syndromes differ in their heterogeneity across different population groups. Some genetic syndromes have variable features in different ethnicities, in part due to specific background exam characteristics such as flat facial profiles or nasal differences; however, other genetic syndromes are similar across different ethnicities. Facial analysis technology is accurate in diagnosing genetic syndromes in populations around the world and is a powerful adjunct to conventional clinical examination. This accuracy also reinforces the concept that genetic syndromes can and should be diagnosed in any ethnicity.

SUMMARY

The increasing amount of data from studies on genetic syndromes in diverse populations is significantly improving our knowledge and approach to dysmorphic patients from various ethnic backgrounds. Optimal management of genetic syndromes requires early diagnosis, including in developing countries.

Mature miR-99a Upregulation in the Amniotic Fluid Samples from Female Fetus Down Syndrome Pregnancies: A Pilot Study

Background and Objective: Although Down syndrome is the most frequent aneuploidy, its pathogenic molecular mechanisms are not yet fully understood. The aim of our study is to quantify-by qRT-PCR-the expression levels of both the mature forms and the pri-miRNAs of the microRNAs resident on chromosome 21 (miR(21)) in the amniotic fluid samples from Down syndrome singleton pregnancies and to estimate the impact of the differentially expressed microRNAs on Down syndrome fetal heart and amniocytes transcriptomes. Materials and methods: We collected amniotic fluid samples harvested by trained obstetricians as part of the second trimester screening/diagnostic procedure for aneuploidies to assess the trisomy 21 status by QF-PCR and karyotyping. Next, we evaluated-by Taqman qRT-PCR-the expression levels of both the mature forms and the pri-miRNA precursors of the microRNAs resident on chromosome 21 in amniotic fluid samples from singleton Down syndrome and euploid pregnancies. Further, we combined miRWalk 3.0 microRNA target prediction with GEO DataSets analysis to estimate the impact of hsa-miR-99a abnormal expression on Down syndrome heart and amniocytes transcriptome. Results: We found a statistically significant up-regulation of the mature form of miR-99a, but not pri-miR-99a, in the amniotic fluid samples from Down syndrome pregnancies with female fetuses. GATHER functional enrichment analysis of miRWalk3.0-predicted targets from Down syndrome amniocytes and fetal hearts transcriptome GEODataSets outlined both focal adhesion and cytokine-cytokine receptor interaction signaling as novel signaling pathways impacted by miR-99a and associated with cardiac defects in female Down syndrome patients. Conclusions: The significant overexpression of miR-99a, but not pri-miR-99a, points towards an alteration of the post-transcriptional mechanisms of hsa-miR-99a maturation and/or stability in the female trisomic milieu, with a potential impact on signaling pathways important for proper development of the heart.

Modular service provision for heterogeneous patient groups: a single case study in chronic Down syndrome care

Background

Service modularity could be promising for organizing healthcare delivery to heterogeneous patient groups because it enables cost reductions while also being responsive towards individual patients’ needs. However, no research on the applicability of modularity in this context exists. To this end, we conducted a qualitative single-case study on chronic healthcare provision for Down syndrome patients, delivered by multidisciplinary pediatric Downteams in the Netherlands, from a modular perspective.

Methods

We conducted six semi-structured interviews with coordinators of multidisciplinary Downteams in six hospitals. In addition, we gathered data by means of observations and analysis of relevant documentation. We transcribed, coded, and analyzed the interviews utilizing the Miles and Huberman approach. The consolidated criteria for reporting qualitative research (COREQ) were applied in this study.

Results

In all six Downteams studied, the modular package for Down syndrome patients (i.e. the visit to the Downteams) could clearly be divided into modules (i.e. the separate consultations with the various professionals), and into different components (i.e. sub-elements of these consultations). These modules and components were linked by different types of customer-flow and information-flow interfaces. These interfaces allowed patients to flow smoothly through the system and allowed for information transfer, respectively.

Conclusion

Our study shows a modular perspective is applicable to analyzing chronic healthcare for a heterogeneous patient group like children with Down syndrome. The decomposition of the various Downteams into modules and components led to mutual insight into each other’s professional practices, both within and across the various Downteams studied. It could be used to increase transparency of delivered care for patients and family. Moreover, it could be used to customize care provision by mixing-and-matching components. More detailed research on chronic modular care provision for patients with DS is needed to explore this.

Molecular mechanisms of congenital heart disease in down syndrome

Down syndrome (DS), as a typical genomic aneuploidy, is a common cause of various birth defects, among which is congenital heart disease (CHD). 40-60% neonates with DS have some kinds of CHD. However, the molecular pathogenic mechanisms of DS associated CHD are still not fully understood. This review summarizes available studies on DS associated CHD from seven aspects so as to provide a crucial and updated overview of what we known so far in this domain.

Vemurafenib Treatment of Pleomorphic Xanthoastrocytoma in a Child With Down Syndrome

Brain tumors are the most common solid neoplasms of childhood, but they are very rarely reported in children with Down Syndrome (DS), who develop more commonly different types of malignancies. In particular, we hereby report the case of an 8-years-old child with DS that presented to our attention for neurological and endocrinological issues. Brain imaging revealed the presence of a mass that was partially resected revealing a histological diagnosis of Pleomorphic Xanthoastrocytoma (PXA), a rare WHO grade II tumor extending from the diencephalic region into the surrounding brain tissue. These tumors can harbor the BRAF mutation p.V600E, targetable by the specific inhibitor Vemurafenib. After confirming the presence of the mutation in the tumor, the patient was treated with Vemurafenib. The treatment proved to be effective, leading to a partial response and a stabilization of the disease. Usually, in patients with DS a reduction of the dose of chemotherapeutic drugs is necessary. Vemurafenib was instead well-tolerated as the only observed adverse effect was grade I skin toxicity. This is, to our knowledge, the first case of a PXA reported in a child with DS and the first DS patient treated with Vemurafenib.

Umbilical artery pulsatility index and half-peak systolic velocity deceleration time in fetuses with trisomy 21

Objective: To analyze placental vascular resistance and the role of placental insufficiency in the etiology of reduced fetal growth in fetuses with trisomy 21 as determined by umbilical artery (UA) Doppler velocimetry.Methods: Second- and third-trimester UA Doppler ultrasound studies were performed in fetuses with trisomy 21 at the time of clinically indicated obstetric ultrasound assessment. The UA pulsatility index (PI) and half-peak systolic velocity deceleration time (hPSV-DT) were measured and recorded. Perinatal outcome was reviewed and the results from UA Doppler velocimetry were compared with birthweight according to gestational age at the time of the delivery.Results: A total of 60 fetuses with trisomy 21 were studied and information from 147 UA Doppler studies was analyzed. Overall, at least one of the UA PI and hPSV-DT values was abnormal in 82% (n = 49) and 90% (n = 54) of the cases, respectively. The incidence of abnormal UA PI values increased with gestational age from 39% (7/18) before 21 weeks to 78% (18/23) after 35 weeks (p < .05). The increase was even more evident for UA hPSV-DT values from 28% (5/18) before 20 weeks to 91% (21/23) after 35 weeks (p < .01). After exclusion of four fetuses with hydrops or isolated hydrothorax/ascites, 16 (29%) were classified at birth as small for gestational age (SGA), 34 (61%) as adequate for gestational age, and six (11%) as large for gestational age, with a mean birthweight z-score of -0.36. When only considering the last Doppler ultrasound assessment prior to delivery, UA PI and hPSV-DT values were abnormal in 73% (41/56, mean z-score = +1.72) and 82% (46/56; mean z-score = -2.18) of the cases, respectively. Mean gestational age at delivery and birth weight were significantly lower in the group with abnormal compared to normal UA PI and hPSV-DT values. Similarly, the incidence of SGA fetuses was significantly higher in the group with abnormal compared to normal UA PI and hPSV-DT values, with 94 (n = 15) and 100% of the 16 SGA newborn infants having abnormal UA PI and hPSV-DT values prior to delivery, respectively.Conclusions: Trisomy 21 fetuses have a progressively higher incidence of abnormal UA impedance indices throughout pregnancy, which suggests developing placental vascular resistance as the pregnancy progresses. This alteration likely begins around the mid second trimester and increases with gestational age; however, increasing placental vascular resistance seems to produce a discrete decrease in fetal growth, despite severe alteration of the UA Doppler impedance indices. As a general hypothesis, we postulate that trisomy 21 fetuses have increasing placental vascular resistance but there may be some factors that protect these fetuses from severe fetal growth restriction.

Growth curves for French people with Down syndrome from birth to 20 years of age

We present new and complete growth charts for 2,598 healthy French children and adolescents with Down syndrome (DS) from 0 to 20 years old, obtained with highly reliable statistical methods. This study is retrospective and addresses data collected over a period of 12 years, monocentric and with a satisfactory representation of the population nationwide. Final occipito-frontal circumference (OFC) is at the fifth percentile compared to WHO charts, with a drop between 12 and 18 months. Final height is at the first percentile compared to WHO charts for girls and boys with two periods of reduced growth velocity: before 36 months and around puberty. We observed no pubertal growth peak for girls. For boys, pubertal growth peak showed to happen earlier and to be less significant than in the general population. When compared to a previous French study with people affected with DS, pubertal growth acceleration begins at a later age for girls and boys; girls in our study are taller at age 15 (+5 cm), but there is no difference for boys at this age. Overweight is more frequent compared to the typical French population. Mean body mass index (BMI) rises rapidly above the 75th percentile of typical French children as early as age 4, with an earlier age for precocious adiposity rebound. The second period for rapid increase of BMI is around 14 years old. When compared to a previous French study with DS, we did not observe any BMI increase, at least up to the age of 14.