The population prevalence of Down's syndrome in England and Wales in 2011

Sleep-disordered breathing in children and adults with intellectual disability: mind the gap!

BACKGROUND

In adults and children with intellectual disability (ID), sleep -disordered breathing (SDB) is thought to be common. However, large epidemiological studies are lacking, and there are few studies on optimal methods of investigation and even fewer randomised, controlled intervention trials of treatment.

METHOD

Peer-reviewed publications from various databases were examined in line with search terms relevant to ID and SDB spanning the years 200-2024.

RESULTS

Findings suggest that, due to comorbid conditions, children and adults with ID may experience both an increased risk of SDB, as well as lower frequency of diagnosis. SDB can compromise the emotional, physical and mental health of individuals with ID. Appropriate treatment when tolerated leads to an improvement in health and well-being and several studies emphasized the importance of consistent follow-up of people with ID - something that is not universally occurring during childhood, in the transition to adulthood and during adulthood itself. As the most frequently occurring form of ID worldwide, we use Down syndrome as a specific example of how diagnosing and treating SDB can lead to improved outcomes.

CONCLUSIONS

This review highlights the importance of identifying SDB in this heterogenous population, recognising the multi-faceted, deleterious consequences of untreated SDB in people with ID, and presents some strategies that can be harnessed to improve diagnosis and management. Until further ID-specific research is available, we urge flexibility in the approach to people with ID and SDB based in guidelines and standard practice developed for the typically developing population.

Higher risk of cerebral palsy, seizures/epilepsy, visual- and hearing impairments, cancer, injury and child abuse in children with congenital anomalies: Data from the EUROlinkCAT study

AIM

The aim is to examine the risk of cerebral palsy, seizures/epilepsy, visual- and hearing impairments, cancer, injury/poisoning and child abuse in children with and without a congenital anomaly up to age 5 and 10 years.

METHODS

This is a population-based data linkage cohort study linking information from the European Surveillance of Congenital Anomalies network (EUROCAT) and birth registries to hospital discharge databases. We included 91 504 live born children with major congenital anomalies born from 1995 to 2014 from nine EUROCAT registries in five countries and 1 960 727 live born children without congenital anomalies (reference children). Prevalence and relative risk (RR) were estimated for each of the co-morbidities using Kaplan-Meier survival estimates.

RESULTS

Children with congenital anomalies had higher risks of the co-morbidities than reference children. The prevalences in the reference children were generally very low. The RR was 13.8 (95% CI 12.5-15.1) for cerebral palsy, 2.5 (95% CI 2.4-2.6) for seizures/epilepsy, 40.8 (95% CI 33.2-50.2) for visual impairments, 10.0 (95% CI 9.2-10.9) for hearing loss, 3.6 (95% CI 3.2-4.2) for cancer, 1.5 (95% CI 1.4-1.5) for injuries/poisoning and 2.4 (95% CI 1.7-3.4) for child abuse.

CONCLUSION

Children with congenital anomalies were more likely to be diagnosed with the specified co-morbidities compared to reference children.

Cerebral organoids with chromosome 21 trisomy secrete Alzheimer's disease-related soluble aggregates detectable by single-molecule-fluorescence and super-resolution microscopy

Understanding the role of small, soluble aggregates of beta-amyloid (Aβ) and tau in Alzheimer's disease (AD) is of great importance for the rational design of preventative therapies. Here we report a set of methods for the detection, quantification, and characterisation of soluble aggregates in conditioned media of cerebral organoids derived from human iPSCs with trisomy 21, thus containing an extra copy of the amyloid precursor protein (APP) gene. We detected soluble beta-amyloid (Aβ) and tau aggregates secreted by cerebral organoids from both control and the isogenic trisomy 21 (T21) genotype. We developed a novel method to normalise measurements to the number of live neurons within organoid-conditioned media based on glucose consumption. Thus normalised, T21 organoids produced 2.5-fold more Aβ aggregates with a higher proportion of larger (300-2000 nm2) and more fibrillary-shaped aggregates than controls, along with 1.3-fold more soluble phosphorylated tau (pTau) aggregates, increased inflammasome ASC-specks, and a higher level of oxidative stress inducing thioredoxin-interacting protein (TXNIP). Importantly, all this was detectable prior to the appearance of histological amyloid plaques or intraneuronal tau-pathology in organoid slices, demonstrating the feasibility to model the initial pathogenic mechanisms for AD in-vitro using cells from live genetically pre-disposed donors before the onset of clinical disease. Then, using different iPSC clones generated from the same donor at different times in two independent experiments, we tested the reproducibility of findings in organoids. While there were differences in rates of disease progression between the experiments, the disease mechanisms were conserved. Overall, our results show that it is possible to non-invasively follow the development of pathology in organoid models of AD over time, by monitoring changes in the aggregates and proteins in the conditioned media, and open possibilities to study the time-course of the key pathogenic processes taking place.

Health-related quality of life and family functioning of primary caregivers of children with down syndrome

Background

Down Syndrome (DS; OMIM #190685), known as trisomy 21, is one of the most common genetic disorders in the human population and the commonest known cause of intellectual disability. The study was conducted to investigate the quality of life (QoL) of children with DS syndrome and its impact on family functioning.

Purpose of study

To assess the quality of life of children with trisomy 21 and the impact of the disorder on the family.

Methods

We used a cross-sectional questionnaire study. The respondents were 52 parents of children with trisomy 21. The following structured questionnaires were used: the PedsQL™ 4.0 Generic Core Scales, the PedsQL™ Family Impact Module and Study-Specific Questionnaire (SSQ).

Results

The combined scores, with a mean value of approximately 55 out of a possible 100 points, indicated a significant impact of the child's genetic defect on family functioning. In the overall QOL, the highest rated domain was physical functioning (x̅ =60.14; SD = 23.82) and the lowest was school functioning (x̅ =51.36; SD = 18.72). Better school functioning (p = 0.022) was reported for girls. The presence of reduced muscle tone also had a negative impact on the child's functioning in the physical (p = 0.036), emotional (p = 0.011), psychosocial (p = 0.027) and overall QOL domains (p = 0.023).

Conclusion

Overall, our results showed that the quality of life of children with trisomy 21 is impaired. There was a positive association between the child's QOL and the QOL of their parents, as well as the general functioning of the child's whole family. For this reason, an improvement in the QOL of parents and the family functioning is closely related to an increased QOL of the child. The continuous deepening of knowledge of QOL in individual trisomy 21 management allows for better preparation and ongoing care for the patients concerned.

Exploring semantic verbal fluency patterns and their relationship to age and Alzheimer's disease in adults with Down syndrome

INTRODUCTION

Adults with Down syndrome (DS) are at ultra-high risk of developing Alzheimer's disease (AD), characterized by poor episodic memory and semantic fluency in the preclinical phase in the general population. We explored semantic fluency performance in DS and its relationship to age, AD, and blood biomarkers.

METHODS

A total of 302 adults with DS at baseline and 87 at follow-up from the London Down Syndrome Consortium cohort completed neuropsychological assessments. Blood biomarkers were measured with the single molecule array technique in a subset of 94 participants.

RESULTS

Poorer verbal fluency performance was observed as age increases. Number of correct words declined in those with AD compared to those without over 2 years and was negatively correlated with neurofilament light (r = -0.37, P = .001) and glial fibrillary acidic protein (r = -0.31, P = .012).

DISCUSSION

Semantic fluency may be useful as an early indicator of cognitive decline and provide additional information on AD-related change, showing associations with biomarkers in DS.

Global health measures from a National Down Syndrome Registry

People with Down syndrome (DS) have a unique medical profile which may impact views of health. We aimed to study the use of global health measures for DS in a national cohort. We prospectively surveyed parents of individuals with DS from the DS-Connect® registry with validated Patient Reported Outcomes Measurement Information System (PROMIS)® instruments of global health. Analyses included use of scoring manuals and the PROMIS® scoring service, descriptive statistics, and t-tests. We received completed surveys from 223 parents of individuals with DS; previously published limitations of the instrument in this population were shown again. T-scores differed from the available comparative standardized scores to these measures from PROMIS® reference population on Fatigue (p < 0.001) and Global Health (p < 0.001), but not on Pain Interference (p = 0.41).

The impact of COVID-19 (Coronavirus) on children and young people with Down syndrome in the United Kingdom

The COVID-19 pandemic had a profound impact across the globe. Evidence suggests children with Special Educational Needs and Disabilities and their families experienced impacts on well-being and disruptions in support from education and health services. This study investigated the impact of measures associated with the COVID-19 pandemic on children and young people (CYP) with Down syndrome in the United Kingdom, specifically changes in speech, language and communication abilities, behavior, social, emotional and mental health and access to education and healthcare services. Forty-six parents/carers of CYP with Down Syndrome (aged 2-25 years) completed an online survey between June and September 2020. Parents/carers frequently reported deterioration in speech, language and communication, literacy and attention skills since the onset of the pandemic. Deterioration in social and emotional wellbeing and behavior, including greater reliance on adults were also reported for some CYP with Down syndrome. Parents reported challenges with home-schooling and reductions in support from education and community services. Preferences for support during COVID-19 were for professional support or from other parents. These findings have implications for the support that is now needed for CYP with Down syndrome and their families and for periods of social restrictions in the future.

Are there foetal extracellular vesicles in maternal blood? Prospects for diagnostic biomarker discovery

Prenatal diagnosis of congenital disease improves clinical outcomes; however, as many as 50% of congenital heart disease cases are missed by current ultrasound screening methods. This indicates a need for improved screening technology. Extracellular vesicles (EVs) have attracted enormous interest in recent years for their potential in diagnostics. EVs mediate endocrine signalling in health and disease and are known to regulate aspects of embryonic development. Here, we critically evaluate recent evidence suggesting that EVs released from the foetus are able to cross the placenta and enter the maternal circulation. Furthermore, EVs from the mother appear to be transported in the reverse direction, whilst the placenta itself acts as a source of EVs. Experimental work utilising rodent models employing either transgenically encoded reporters or application of fluorescent tracking dyes provide convincing evidence of foetal-maternal crosstalk. This is supported by clinical data demonstrating expression of placental-origin EVs in maternal blood, as well as limited evidence for the presence of foetal-origin EVs. Together, this work raises the possibility that foetal EVs present in maternal blood could be used for the diagnosis of congenital disease. We discuss the challenges faced by researchers in translating these basic science findings into a clinical non-invasive prenatal test.

Proportion of Chromosomal Disorders and Their Patterns among Births with Congenital Anomalies in Africa: A Systematic Review and Meta-Analyses

Introduction

Worldwide, surveys have shown that the frequency of chromosomal disorders among births with congenital anomalies varies greatly from country to country. It is well known that chromosomal disorders are an important cause of premature death or life-long disability; however, the absence of local epidemiological data on their birth prevalence and outcomes impedes policy and service development in many countries and continents. Therefore, the current systematic review and meta-analysis intend to show the pooled proportion of chromosomal disorders among births with congenital anomalies in Africa.

Methods

From PubMed, Cochrane Library, and Google Scholar, we systematically reviewed and meta-analyzed the studies that examined the incidence, prevalence, and types of chromosomal disorders using PRISMA guidelines. A weighted inverse variance random-effects model was used to estimate the pooled proportion of chromosomal disorders among births with congenital anomalies.

Results

From the total of 3,569 studies identified, 1,442 were from PubMed, 108 were from Cochrane Library, 1,830 were from Google Scholar, and 189 were from other sources. After duplication was removed, a total of 844 articles remained (2725 were removed by duplication). Finally, 144 full-text studies were reviewed and 60 articles with 52,569 births having congenital anomalies met the inclusion criteria and were selected for this meta-analysis. The pooled proportion of chromosomal disorders among births with congenital anomalies was 8.94% (95% CI; 7.02, 10.86; I ² = 98.8%; p < 0.001). Conclusions and Future Implications. In the current systematic review and meta-analysis, the pooled proportion of chromosomal disorders among births with congenital anomalies in Africa was small. Down syndrome (trisomy 21) accounted for more than 80% of chromosomal disorders. The pooled proportion of chromosome disorders was the highest in North African regions and countries compared to other regions of the continent. Healthcare managers should focus on establishing proper cytogenetic diagnostic facilities in collaboration with well-trained genetic counseling services in the continent.

Intervention for Treating Depression in Parents of Children with Intellectual Disability of Down's Syndrome: A Sample of Nigerian Parents

A good number of parents of children with Down syndrome are prone to depressive disorders. The depressive feelings are attributed to negative perceptions of the situation, self, and the future. Given this, we explored the impact of the family health model of rational-emotive behavior therapy on depressive symptoms in parents of children with intellectual disability of Down syndrome in the COVID-19 pandemic era. This is a randomized pretest-posttest control group design that recruited 88 parents of children with intellectual disability of Down syndrome. We measured the depressive symptoms in parents at Time 1, Time 2, and Time 3 using the Beck depressive inventory and Hamilton depression rating scale. We adopted a family health model rational emotive behaviour therapy intervention in treating the depressive symptoms affecting the parents. The analysis of covariate results showed that at initial assessment there was no significant difference between the treatment group and comparison group at baseline evaluation of depressive symptoms in participants. At the posttest, it had a significant effect on the intervention on participants' depressive symptoms. Likewise, a follow-up result still shows that intervention had a significant effect on participants' depressive symptoms of participants. In conclusion, this study suggests that treatment variable accounted for the effect in decreasing depressive symptoms scores of participants.

Down syndrome live births following assisted reproductive technology in Japan: a nationwide survey between 2007 and 2016

PURPOSE

The use of assisted reproductive technology (ART) and prenatal genetic testing have become more widespread in line with an increase in maternal age. However, the effect of the introduction of non-invasive prenatal testing (NIPT) in April 2013 on pregnancy outcomes in Japan, including the prevalence of Down syndrome live births following ART, has not been investigated. This study aimed to evaluate the trends in the prevalence of Down syndrome live births following ART in Japan.

METHODS

This population-based retrospective study used the Japanese nationwide ART registry. All clinical pregnancies resulting in live births, stillbirths, and termination of pregnancy (TOP) following ART from 2007 to 2016 were included. Pregnancy outcomes involving infants with Down syndrome were evaluated.

RESULTS

Among 351,808 pregnancies, the proportion of mothers with advanced age increased significantly from 2007 to 2016 (from 49.5 to 62.4% and 8.9 to 17.8% for mothers aged ≥ 35 and ≥ 40 years, respectively). The proportion of live births with Down syndrome was 77.3% in 2007, which remained consistent until 2012, but then decreased significantly to 45.1% after 2013 (P < 0.001). The prevalence of Down syndrome live births increased up to 2012 (19.5/10,000 live births), decreased significantly in 2013 (12.1/10,000 live births), and then remained almost stable (11.1-14.7/10,000 live births).

CONCLUSION

The introduction of NIPT balanced the prevalence of Down syndrome live births following ART with recent increasing maternal age in Japan.

Rodent Modeling of Alzheimer's Disease in Down Syndrome: In vivo and ex vivo Approaches

There are an estimated 6 million people with Down syndrome (DS) worldwide. In developed countries, the vast majority of these individuals will develop Alzheimer's disease neuropathology characterized by the accumulation of amyloid-β (Aβ) plaques and tau neurofibrillary tangles within the brain, which leads to the early onset of dementia (AD-DS) and reduced life-expectancy. The mean age of onset of clinical dementia is ~55 years and by the age of 80, approaching 100% of individuals with DS will have a dementia diagnosis. DS is caused by trisomy of chromosome 21 (Hsa21) thus an additional copy of a gene(s) on the chromosome must cause the development of AD neuropathology and dementia. Indeed, triplication of the gene APP which encodes the amyloid precursor protein is sufficient and necessary for early onset AD (EOAD), both in people who have and do not have DS. However, triplication of other genes on Hsa21 leads to profound differences in neurodevelopment resulting in intellectual disability, elevated incidence of epilepsy and perturbations to the immune system. This different biology may impact on how AD neuropathology and dementia develops in people who have DS. Indeed, genes on Hsa21 other than APP when in three-copies can modulate AD-pathogenesis in mouse preclinical models. Understanding this biology better is critical to inform drug selection for AD prevention and therapy trials for people who have DS. Here we will review rodent preclinical models of AD-DS and how these can be used for both in vivo and ex vivo (cultured cells and organotypic slice cultures) studies to understand the mechanisms that contribute to the early development of AD in people who have DS and test the utility of treatments to prevent or delay the development of disease.

The ASCEND study: protocol for a feasibility study to evaluate an early social communication intervention for young children with Down syndrome

BACKGROUND

Down syndrome is the most common cause of learning disability, affecting approximately 1 in every 700 babies. Children with Down syndrome have particular difficulties with speech and language. This makes it challenging for them to participate fully in life, access healthcare services and educational opportunities. Improving the language skills of young children with Down syndrome is vital for their future social and emotional well-being and behaviour, and consequently contribution to society. As Down syndrome is detected before or at birth, we can provide support from early on. There are currently no standard interventions for improving the language skills of children with Down syndrome under the age of 36 months. Evidence suggests that early parent-based interventions may be effective in improving language outcomes. In partnership with parents and speech and language therapists, we have co-developed an intervention focusing on early social communication skills and our preliminary work shows that it can lead to better language in children with Down syndrome. Our aim is to carry out a feasibility study which will inform a future pilot/full trial to test whether the intervention is effective in improving language skills before children with Down syndrome start school.

METHODS

This is a two-arm feasibility randomised controlled trial (RCT), with 1:1 randomisation stratified by trial site comparing the intervention (plus standard NHS speech and language therapy) with no intervention (standard NHS speech and language therapy only). We aim to recruit between 25 and 30 children with Down syndrome aged between 11 and 36 months. Sites are defined by the geographical boundaries of three National Health Service (NHS) Trusts. Recruitment is from NHS Speech and Language Therapist caseloads within the 3 Trusts, and self-referral. In the intervention arm, parents/guardians will receive brief training on the parent-based intervention and a manual to follow with their child for 10 weeks. The children's language and early communication skills and family health outcomes will be assessed by a blinded assessor at baseline, post-intervention and 6 month follow-up. Questionnaire and semi-structured interviews will explore the acceptability of the intervention to parents and SLTs.

DISCUSSION

The feasibility study's outcomes will determine whether it would be viable to progress to a full-trial and whether adjustments need to made to the procedures, data collection methods, intervention delivery and the intensity of support needed. We want to assess whether our early intervention can be delivered and rolled out through NHS Speech and Language Therapy (SLT) Services. We anticipate that NHS SLT Services will need to make ongoing changes due to the COVID-19 pandemic, so it is likely that we will need to make adjustments for the definitive trial. We will also calculate descriptive statistics of the language outcome measure which we will use for any future sample size calculation.

TRIAL REGISTRATION

ISRCTN13902755. Registered on 25 August 2020. http://www.isrctn.com/ISRCTN13902755.

Educational experiences of pupils with Down syndrome in the UK

BACKGROUND

Though research has identified that increasing numbers of pupils with Down syndrome (DS) in the UK are educated in mainstream schools, little detailed information about the educational experiences of pupils with DS is available.

AIMS

This study explored parent views of the educational experiences of pupils with DS attending UK schools (Reception-Year 11) using an online survey.

METHODS AND PROCEDURES

Responses from 569 parents were collected.

OUTCOMES AND RESULTS

Overall, 65 % of pupils were in mainstream schools but this was more common at primary (80 %) than secondary school (37 %). Pupils participated in most academic and social activities alongside their peers but were commonly not accessing all opportunities. Many pupils received additional support in school including external professional services. Frequent meetings between parents and teachers/teaching assistants indicated high levels of collaboration. Teachers and teaching assistants were largely viewed as responsible for children's learning. Overall, respondents reported satisfaction with provision.

CONCLUSIONS AND IMPLICATIONS

Many pupils with DS in the UK are able to access a broad and balanced curriculum but this is not the case for all. Ways in which provision can be enhanced are discussed.

Objective and Subjective Prevalence of Obstructive Sleep Apnoea/Hypopnoea Syndrome in UK Adults with Down Syndrome: A Strong Marker for Diurnal Behavioural Disturbances

Prior to this study, the prevalence of obstructive sleep apnoea/hypopnoea syndrome (OSAHS) in adults with Down syndrome was unknown. We hypothesized that unrecognised OSAHS could have an additional deleterious impact on mood and behavioural disturbances in this group of people.

AIMS

To assess the prevalence of OSAHS in adults with Down syndrome in the United Kingdom, subjectively and objectively, and ascertain its association with diurnal behavioural disturbances.

METHOD

Cross-sectional questionnaire study with home sleep apnoea testing (HSAT) during 2011-2015 across the four nations of the United Kingdom. Participants were adults aged ≥16 years with Down syndrome. Main outcome measures were: self- or caregiver-completed questionnaire data, including the Pictorial Epworth Sleepiness Scale (pESS), selected domains of the Developmental Behavioural Checklist for Adults (DBC-A), anthropometric measures, and symptoms of OSAHS. Objective prevalence was undertaken in a sample of responders using HSAT.

RESULTS

Responses were received from 1321/5270 participants (25%), with 1105 valid responses (21%). Eighty-one participants (7%) reported a prior diagnosis of OSA, of whom 38 were receiving therapy. Using validated algorithms, a diagnosis of OSAHS was probable in 366 participants (35%), who were younger, with higher BMI and higher mean total pESS (p < 0.0001). A total of 23% of participants had a pESS > 10. OSAHS was a strong marker for behavioural disturbances on the DBC-A depression, disruption and anti-social subscales (p < 0.001). Of 149 individuals who underwent HSAT, 42% were diagnosed with OSAHS.

CONCLUSIONS

Untreated OSAHS in Down syndrome is common and associated with behavioural and mood disturbances. Improving awareness of OSAHS amongst adults with Down syndrome, their families and healthcare professionals is essential.

EUROlinkCAT protocol for a European population-based data linkage study investigating the survival, morbidity and education of children with congenital anomalies

INTRODUCTION

Congenital anomalies (CAs) are a major cause of infant mortality, childhood morbidity and long-term disability. Over 130 000 children born in Europe every year will have a CA. This paper describes the EUROlinkCAT study, which is investigating the health and educational outcomes of children with CAs for the first 10 years of their lives.

METHODS AND ANALYSIS

EUROCAT is a European network of population-based registries for the epidemiological surveillance of CAs. EUROlinkCAT is using the EUROCAT infrastructure to support 22 EUROCAT registries in 14 countries to link their data on births with CAs to mortality, hospital discharge, prescription and educational databases. Once linked, each registry transforms their case data into a common data model (CDM) format and they are then supplied with common STATA syntax scripts to analyse their data. The resulting aggregate tables and analysis results are submitted to a central results repository (CRR) and meta-analyses are performed to summarise the results across all registries. The CRR currently contains data on 155 594 children with a CA followed up to age 10 from a population of 6 million births from 1995 to 2014.

ETHICS

The CA registries have the required ethics permissions for routine surveillance and transmission of anonymised data to the EUROCAT central database. Each registry is responsible for applying for and obtaining additional ethics and other permissions required for their participation in EUROlinkCAT.

DISSEMINATION

The CDM and associated documentation, including linkage and standardisation procedures, will be available post-EUROlinkCAT thus facilitating future local, national and European-level analyses to improve healthcare. Recommendations to improve the accuracy of routinely collected data will be made.Findings will provide evidence to inform parents, health professionals, public health authorities and national treatment guidelines to optimise diagnosis, prevention and treatment for these children with a view to reducing health inequalities in Europe.

Optimal age and outcome measures for Alzheimer's disease prevention trials in people with Down syndrome

INTRODUCTION

People with Down syndrome (DS) typically develop Alzheimer's disease (AD) neuropathology before age 40, but a lack of outcome measures and longitudinal data have impeded their inclusion in randomized controlled trials (RCTs).

METHODS

Cohort study. Event-based and dose-response Emax models were fitted to longitudinal cognitive data, to stage AD and determine the earliest ages of decline. Results informed sample size estimations for hypothetical RCTs of disease-modifying treatments that reduced decline by 35% or 75%.

RESULTS

Seventy-five percent of participants progressed or remained stable in the AD staging model; effect sizes varied by age group and tests. Varied treatment effects could be detected with 50-200 people per arm when using sensitive cognitive outcome measures and targeting recruitment to ages 36 to 45 years.

DISCUSSION

Efficient RCTs of AD preventative treatments can be conducted in the DS population using sensitive outcome measures to monitor early decline. Dose-response models could help tailor future RCTs.

Piloting the use of global health measures in a Down syndrome clinic

PURPOSE

People with Down syndrome (DS) have a unique medical profile which may impact views of health. We aimed to explore the use of global health measures in DS.

METHODS

Prospective survey in the Mass General Hospital Down Syndrome Program (MGH DSP) from December 2018 to July 2019 with Patient Reported Outcomes Measurement Information System (PROMIS)® instruments of global health. Analyses included use of scoring manuals, descriptive statistics and dependent samples t test.

RESULTS

Seventeen adolescents, 48 adults with DS and 88 caregivers returned surveys; 137 were complete. Incomplete responses and notes showed limitations of the instruments in this population. Global health T-scores did not differ from the available comparative standardized scores to these measures from PROMIS® reference population (p > 0.05).

CONCLUSIONS

In the MGH DSP, pilot global health instruments were completed by some adults with DS and caregivers, with some limitations and scores similar to the PROMIS® reference population.

Effect of antibiotics in preventing hospitalizations from respiratory tract infections in children with Down syndrome

BACKGROUND

Children with Down syndrome (DS) are at high risk of respiratory tract infections (RTIs) due to anatomical variations, comorbidities, and immune system immaturity. Evidence on interventions to reduce this risk is incomplete. This study aims to quantify the effect of antibiotics prescribed for RTIs in primary care on the subsequent risk of RTI-related hospitalization for children with DS versus controls.

METHODS

We conducted a retrospective cohort study of 992 children with DS and 4874 controls managed by UK National Health Service General Practitioners (GPs) and hospitals as identified in CALIBER (Clinical disease research using LInked Bespoke studies and Electronic health Records), 1997-2010. Univariate and multivariate logistic regression were undertaken.

RESULTS

In children with DS, the prescription of antibiotics following an RTI-related GP consultation did not significantly reduce the risk of RTI-related hospitalization in the subsequent 28 days (risk with antibiotics, 1.8%; without, 2.5%; risk ratio, 0.699; 95% confidence interval, 0.471-1.036). Subgroup analyses showed a risk reduction only in infants with DS, after adjustment for covariates. There was no reduction in risk for controls, overall or across subgroups.

CONCLUSIONS

In conclusion, while prescription of antibiotics following RTI-related GP consultations were effective for infants with DS in reducing subsequent RTI-related hospitalization, this was not the case for older children with DS. We would encourage further high-quality cohort and randomized controlled trials to interrogate this finding, and to examine the impact of antibiotics on other endpoints, including symptom duration.

Low Rates of Preventive Healthcare Service Utilization Among Adolescents and Adults With Down Syndrome

INTRODUCTION

People with Down syndrome have health risks that require specific lifelong preventive health care. With increasing life expectancy, people with Down syndrome also face health conditions typical of their unaffected peers and thus need coordinated health care. The purpose of this study is to describe rates of age/sex- and Down syndrome-specific preventive healthcare activities among adolescents and adults with Down syndrome.

METHODS

Using Medicaid claims (2006-2010) in California, Colorado, Michigan, and Pennsylvania, the cohort was defined as people with Down syndrome aged ≥12 years seen by primary care providers and enrolled in Medicaid for ≥45 of 60 months without dual Medicare enrollment (n=3,501). Age focus-consistent primary care providers were defined as having a focus concordant with a patient's age: 12-17 years, child or mixed-focus; ≥26 years, adult or mixed-focus; 18-25 years, any focus. Differences in healthcare activities were evaluated using Pearson's chi-square, Fisher's exact, and Kruskal-Wallis tests. Analyses were performed in 2015-2017.

RESULTS

Of the cohort, 79% had an age focus-consistent primary care provider. However, 40% of adults aged ≥26 years received care from a child-focused primary care provider. Only 43% with an age focus-consistent provider had ≥1 well examination (age focus-inconsistent primary care provider: 35%, p<0.001). Most preventive activities had poor rates (<50%) regardless of age focus consistency between provider and patient age or whether they were age/sex- or Down syndrome-specific (well examinations; vaccinations; sleep apnea; hearing; and breast, cervical, and colon cancer screenings). Lipids, vision, and thyroid screenings reached moderate levels (50% to <80%).

CONCLUSIONS

Rates of age/sex- and Down syndrome-specific preventive recommendations were low among adolescents and adults with Down syndrome, regardless of the age focus consistency of their primary care provider. This represents a significant opportunity to improve primary care in this vulnerable population.

Orthodontics in patients with significant medical co-morbidities

A wide variety of patients with medical co-morbidities may present to general orthodontic practice. It is important for the treating clinician to have a general understanding of key medical conditions that may impact upon the treatment and management options. This clinical supplement provides a treatment-focused summative update for the orthodontist regarding significant medical co-morbidities, their general prevalence and an exploration of potential impacts upon orthodontic treatment. This review also discusses the significance of key medications and provides suggestions for the safe provision of orthodontic treatment.

Prospective Trial of CPAP in Community-Dwelling Adults with Down Syndrome and Obstructive Sleep Apnea Syndrome

Adults with Down syndrome (DS) are predisposed to obstructive sleep apnoea (OSA), but the effectiveness and acceptability of continuous positive airway pressure treatment (CPAP) in this group has rarely been formally assessed. This study was designed as a pilot randomised, parallel controlled trial for one month, continuing as an uncontrolled cohort study whereby the control group also received the intervention. Symptomatic, community-dwelling DS individuals exhibiting ≥10 apnoeas/hypopneas per hour in bed on a Type 3 home sleep study were invited to participate in this study, with follow-up at 1, 3, 6, and 12 months from baseline. Measurements of sleepiness, behaviour, cognitive function and general health were undertaken; the primary outcome was a change in the pictorial Epworth Sleepiness Scale (pESS) score. Twenty-eight participants (19 male) were enrolled: age 28 ± 9 year; body mass index 31.5 ± 7.9 kg/m2; 39.6 ± 32.2 apnoeas/hypopneas per hour in bed; pESS 11 ± 6/24. The pilot randomised controlled trial at one month demonstrated no change between the groups. At 12 months, participant (p = 0.001) pESS and Disruptive (p < 0.0001), Anxiety/Antisocial (p = 0.024), and Depressive (p = 0.008) behaviour scores were reduced compared to baseline. Improvement was noted in verbal (p = 0.001) and nonverbal intelligence scores (p = 0.011). General health scores also improved (p = 0.02). At the end of the trial, 19 participants continued on treatment. Use of CPAP in adults with DS and OSA led to a number of significant, sustained improvements in sleepiness and behavioural/emotional outcomes at 12 months.

Parent-Reported Contribution of Family Variables to the Quality of Life in Children with Down Syndrome: Report from an International Study

PURPOSE

The intent of this study was to determine parents' views of the contribution of family variables to the quality of life (QoL) of children with Down Syndrome (DS). Based on prior research, we hypothesized that parents would report that family variables reflecting positive aspects of family functioning contributed to better QoL; and family variables reflecting the negative aspects of family functioning contributed to poorer QoL.

DESIGN AND METHODS

A cross-sectional study was carried out. Invitation letters were sent to DS support groups. Upon agreement, the parents of the children were sent a link to an online survey that included a consent form, demographic questionnaire, and child and family measures.

RESULTS

Results demonstrated the contribution of family demands to children's interpersonal relations. Family appraisals concerning the child and the family's ability predicted the children's physical and material well-being, personal development, self-determination, social inclusion, interpersonal relations, and rights. Family problem-solving served as a prominent predictor for children's physical and emotional well-being, personal development, interpersonal relations, and rights. Also, family resources predicted various aspects of children's QoL including physical, emotional, and material well-being, self-determination, social inclusion, interpersonal relations, and rights.

CONCLUSION

Results confirmed the significant relationship between family and children's QoL variables. Family appraisal and family problem-solving were especially identified as significant predictors of children's QoL that can be targeted for family interventions, since the family variables are modifiable aspects of family life.

PRACTICE IMPLICATIONS

Nurses can use current findings to develop interventions to enhance QoL of children with DS and families.

Estimation of the number of people with Down syndrome in Europe

We aimed to estimate the nonselective live birth prevalence, actual live birth prevalence, reduction percentage because of selective terminations, and population prevalence for Down syndrome (DS) in European countries. The number of people with DS alive in a country was estimated by first modeling the number of live births of children with DS by year of birth. Subsequently, for these different years of birth, survival curves for people with DS were constructed and then applied to these yearly estimates of live births with DS. For Europe, 2011-2015, we estimate 8,031 annual live births of children with DS, which would have been around 17,331 births annually, absent selective terminations. The estimated reduction of live birth prevalence was, on average, 54%, varying between 0% in Malta and 83% in Spain. As of 2015, we estimate 417,000 people with DS are living in Europe; without elective terminations, there would have been about 572,000 people with DS, which corresponds to a population reduction rate of 27%. Such statistics can be important barometers for prenatal testing trends and resource allocation within countries. Disability awareness initiatives and public policy initiatives can also be better grounded with these more precise estimates.

A Cross-Sectional Comparison of the Prevalence of Obstructive Sleep Apnea Symptoms in Adults With Down Syndrome in Scotland and Japan

Small studies in Western populations report a high prevalence of obstructive sleep apnea (OSA) in adults with Down syndrome. To date, ethnic differences have not been explored. A questionnaire sent to 2,752 adults with Down syndrome aged ≥16 years in Scotland and Japan (789 valid responses) estimated OSA prevalence based on reported symptoms. Symptoms were common in both countries, with snoring (p = 0.001) and arousals (p = 0.04) more prevalent in Japan. Estimated OSA prevalence in adults with Down syndrome was similar in the two countries, and raised in comparison with the general adult population (19.6% in Scotland and 14.3% in Japan; p = 0.08), though BMI was a confounder. Identification and treatment of OSA is recommended in adults with Down syndrome, regardless of ethnicity.

Treatment for Post-hemorrhagic Ventricular Dilatation: A Multiple-Treatment Meta-Analysis

Objective: To perform a systematic review and multiple-treatment meta-analysis for the treatment of premature infants with post-hemorrhagic ventricular dilatation (PHVD), to prevent death or long-term neuro-disability. Design/Method: A systematic review was performed using PubMed, EMBASE, and the Cochrane Library. A free-word search was performed to identify likely relevant literature intervention trials of PHVD in preterm infants. Initially, network mapping was performed followed by performing a Bayesian random-effects model using the Markov chain Monte Carlo method. Areas under the cumulative ranking curve (SUCRA) were calculated as a measure of the probability that each intervention was likely to be the 1st, 2nd, 3rd, etc. best therapy. Primary outcome measure was death or moderate or severe neurodevelopmental outcome at or beyond 12 months of corrected age. Results: Ten different trials were identified, enrolling 700 individuals (449 for the primary outcome). Seven intervention categories were identified, and of the 15 possible pair comparisons, 6 have been studied directly. In the multiple-treatment meta-analysis, no comparison reached conventional levels of statistical significance. Drainage Irrigation and Fibrinolytic Therapy (DRIFT) had the highest probability of being the best treatment for the primary outcome (82.1%), followed by CSF removal (10.8%), conservative management (6.7%), and then diuretic therapy (0.4%). Conclusions: PHVD is a significant cause of death and disability in developed countries, yet few therapeutic options have so far been trialed. While new therapies are urgently needed for these infants, at present, NMA shows that DRIFT appears to be the most likely candidate to improve outcomes after sIVH.

The Population Prevalence, Associations of Congenital Heart Defect and Mortality Risk for Down's Syndrome in South Korea Based on National Health Insurance Service (NHIS) Data

Background

In the present study, we estimated the population prevalence, associations of congenital heart defect (CHD) and mortality risk for DS using data from National Health Insurance Service (NHIS) and Rare Diseases Registry (RDR).

Methods

We collected data on subjects with DS who were registered in the RDR between 2010 and 2015. To estimate associations of CHD and mortality risk of DS, the data of DS subjects were compared with 1:5 age- and sex-matched controls.

Results

In 2015, 2077 individuals with DS were identified out of the total population of 51,574,044 South Koreans and the prevalence was 4.03 per 100,000 persons. The trend of DS population prevalence across 10-year-old intervals showed a peak in the group under the age of 10 years (26.0 per 100,000 persons) and then declined sharply after the age of 20 years (0.98 per 100,000 persons at 30-39 years of age). In subjects with DS, the frequencies of atrial septal defect [odds ratios (OR) =65.9; 95% CI, 84.1-99.1], ventricular septal defect (OR = 88.1, 95% CI, 57.9-134.1), patent ductus arteriosus (OR = 56.9, 95% CI, 40.1-80.8), tetralogy of fallot (OR = 42.1, 95% CI, 19.3-92.3), or atrioventricular septal defect (OR = 510.0, 95% CI, 126.7-999.0) were higher than those of age- and sex-matched controls. The risk of death in patients with DS was significantly higher than that of age- and sex-matched controls [hazard ratio (HR) =41.7, 95% CI 20.0-87.0].

Conclusion

In South Korea, the DS population prevalence was 4.03 per 100,000 persons in 2015. The subjects with DS were more likely to accompany CHD and have higher mortality risk than healthy controls.

Down syndrome and parental depression: A double hit on early expressive language development

BACKGROUND AND AIMS

Down syndrome (DS) is often characterised by intellectual disability with particular difficulties in expressive language. However, large individual differences exist in expressive language across development in DS. In the general population, one of the factors associated with variability in this domain is parental depression. We investigated whether this is also the case in young children with DS.

METHODS

Thirty-eight children with DS between 8 and 48 months of age participated in this study. Their parents reported on the children's receptive and expressive vocabularies (MacArthur-Bates Communicative Development Inventory) and on parental depression. Furthermore, an experimenter-led standardized developmental assessment (Mullen Scales of Early Learning) was administered to the children to test five domains: gross motor, fine motor, visual reception, receptive language, and expressive language.

RESULTS

A cross-sectional developmental trajectories analysis demonstrated that expressive language developed at a slower rate in children with DS whose parent reported depression than in those whose parent did not. No differences between groups were found in any other domain.

CONCLUSION

Parental depression is associated with slower rate of expressive language development in young children with DS. These findings suggest that DS and parental depression may constitute a double hit leading to increased difficulties in the development of expressive language.

Gesell Developmental Schedules scores and the relevant factors in children with Down syndrome

Background Down syndrome (DS) is a common chromosomal disease resulting in neurodegeneration. Cognitive competence has been assessed among adults with DS using various methods because DS patients have a tendency to develop Alzheimer's disease (AD) after middle age. However, research describing cognitive assessments in DS children is not as many as in DS adults, let alone with regard to performed analyses to determine factors that predict cognitive assessments. In this study, we evaluated the Gesell Developmental Schedules (GDS) scores and their associations with the relevant biochemical indicators and demographic factors in DS children. Methods All the subjects underwent GDS testing. The plasma amyloid-β (Aβ) peptide and serum vitamin A (VA) values were measured with enzyme-linked immunosorbent assay and high-performance liquid chromatography, and in the meanwhile, the demographic information of the subjects was collected. Results Forty-six DS children were recruited for this study. The GDS scores of children with DS were lower than those in children without DS. The plasma Aβ40 and Aβ42 levels were negatively associated with the GDS scores. Moreover, the GDS scores of the non-VA deficiency (NVAD) group were significantly higher than those of the VA deficiency (VAD) group. Certain demographic characteristics, such as the paternal labor intensity and paternal educational status, were relevant factors with regard to the GDS scores of the DS children. Conclusions This study determined that DS children exhibited abnormal GDS scores which indicated developmental delay of children with DS; the levels of plasma Aβ40, Aβ42 and serum VA were influential biochemical indicators and the paternal labor intensity and educational status were related demographic factors.

Birth incidence, deaths and hospitalisations of children and young people with Down syndrome, 1990-2015: birth cohort study

OBJECTIVE

To investigate current Down syndrome live birth and death rates, and childhood hospitalisations, compared with peers.

SETTING

General community.

PARTICIPANTS

All live births with Down syndrome, 1990-2015, identified via Scottish regional cytogenetic laboratories, each age-sex-neighbourhood deprivation matched with five non-Down syndrome controls. Record linkage to Scotland's hospital admissions and death data.

PRIMARY OUTCOME

HRs comparing risk of first hospitalisation (any and emergency), readmission for children with Down syndrome and matched controls were calculated using stratified Cox proportional hazards (PH) model, and length of hospital stay was calculated using a conditional log-linear regression model.

RESULTS

689/1479 (46.6%) female and 769/1479 (51.9%) male children/young people with Down syndrome were identified (1.0/1000 births, with no reduction over time); 1235 were matched. 92/1235 (7.4%) died during the period, 18.5 times more than controls. More of the Down syndrome group had at least one admission (incidence rate ratio(IRR) 72.89 (68.72-77.32) vs 40.51 (39.15-41.92); adjusted HR=1.84 (1.68, 2.01)) and readmissions (IRR 54.85 (51.46-58.46) vs 15.06 (14.36-15.80); adjusted HR=2.56 (2.08, 3.14)). More of their admissions were emergencies (IRR 56.78 (53.13-60.72) vs 28.88 (27.73-30.07); first emergency admission adjusted HR=2.87 (2.61, 3.15)). Children with Down syndrome had 28% longer first admission after birth. Admission rate increased from 1990-2003 to 2004-2014 for the Down syndrome group (from 90.7% to 92.2%) and decreased for controls (from 63.3% to 44.8%).

CONCLUSIONS

We provide contemporaneous statistics on the live birth rate of babies with Down syndrome, and their childhood death rate. They require more hospital admissions, readmissions emergency admissions and longer lengths of stays than their peers, which has received scant research attention in the past. This demonstrates the importance of statutory planning as well as informal support to families to avoid added problems in child development and family bonding over and above that brought by the intellectual disabilities associated with Down syndrome.

Health comorbidities and cognitive abilities across the lifespan in Down syndrome

BACKGROUND

Down syndrome (DS) is associated with variable intellectual disability and multiple health and psychiatric comorbidities. The impact of such comorbidities on cognitive outcomes is unknown. We aimed to describe patterns of physical health and psychiatric comorbidity prevalence, and receptive language ability, in DS across the lifespan, and determine relationships with cognitive outcomes.

METHODS

Detailed medical histories were collected and cognitive abilities measured using standardised tests for 602 individuals with DS from England and Wales (age range 3 months to 73 years). Differences in prevalence rates between age groups and between males and females were determined using chi-squared or Fisher's exact tests. In adults, rates for psychiatric comorbidities were compared to expected population rates using standardised morbidity ratios (SMRs). Adapted ANCOVA functions were constructed to explore age and sex associations with receptive language ability across the lifespan, and regression analyses were performed to determine whether the presence of health comorbidities or physical phenotypes predicted cognitive abilities.

RESULTS

Multiple comorbidities showed prevalence differences across the lifespan, though there were few sex differences. In adults, SMRs were increased in males and decreased in females with DS for schizophrenia, bipolar disorder, and anxiety. Further, SMRs were increased in both males and females with DS for dementia, autism, ADHD, and depression, with differences more pronounced in females for dementia and autism, and in males for depression. Across the lifespan, receptive language abilities increasingly deviated from age-typical levels, and males scored poorer than females. Only autism and epilepsy were associated with poorer cognitive ability in those aged 16-35 years, with no relationships for physical health comorbidities, including congenital heart defects.

CONCLUSIONS

Our results indicate the prevalence of multiple comorbidities varies across the lifespan in DS, and in adults, rates for psychiatric comorbidities show different patterns for males and females relative to expected population rates. Further, most health comorbidities are not associated with poorer cognitive outcomes in DS, apart from autism and epilepsy. It is essential for clinicians to consider such differences to provide appropriate care and treatment for those with DS and to provide prognostic information relating to cognitive outcomes in those with comorbidities.

Using mouse models to understand Alzheimer's disease mechanisms in the context of trisomy of chromosome 21

People who have Down syndrome are at significantly elevated risk of developing early onset Alzheimer's disease that causes dementia (AD-DS). Here we review recent progress in modeling the development of AD-DS in mouse models. These studies provide insight into mechanisms underlying Alzheimer's disease and generate new clinical research questions. In addition, they suggest potential new targets for disease prevention therapies.

Bone mineral density from early to middle adulthood in persons with Down syndrome

BACKGROUND

While accelerated ageing is recognised among individuals with Down syndrome (DS), the trajectory of their bone health across adulthood remains poorly understood.

METHODS

This study aimed to determine the age-related loss of bone mineral density (BMD) of the lumbar spine in 128 adults with DS aged 18 to 54 years compared with 723 counterparts without DS.

RESULTS

Men and women with DS had lower level of BMD than counterparts without DS across age groups. Magnitude of decrement in BMD as reflected in the z-scores was similar between younger and older men with DS. Older women with DS, on the contrary, showed greater decrement in older ages especially in their fourth decade of life. Osteopenia and osteoporosis as defined using age-specific and gender-specific T-scores affected greater number of men with DS (38% and 25%) than women (17% and 17%) aged 40-49 years.

CONCLUSIONS

Findings supported adults with DS, especially men, to have early bone mineral testing.

Plasma neurofilament light chain: A potential prognostic biomarker of dementia in adult Down syndrome patients

People with Down syndrome (DS) are at high risk of developing Alzheimer disease (AD) with aging. The diagnosis and treatment trials are hampered by a lack of reliable blood biomarkers. Plasma neurofilament light chain (NfL) is one of the established biomarkers of AD, suggesting that it may be useful as an indicator of dementia in DS patients. The aims of this study were: 1) to examine whether plasma levels of NfL in DS patients are correlated with decreased adaptive behavior scores one year after sample collection, and 2) to compare plasma levels of NfL in adults with DS and an age-matched healthy control population. In this study, plasma levels of NfL in 24 patients with DS and 24 control participants were measured by the single-molecule immunoarray (Simoa) method. We observed significantly increased plasma NfL levels in the DS compared with the control group. There was a significant correlation between age and levels of plasma NfL in both groups. This age-dependent elevation was steeper in the DS compared with the control group. Moreover, elevated plasma NfL was associated with decreased adaptive behavior scores one year later, after age-adjustment. Previously reported blood-based biomarkers available in Simoa for DS, plasma total tau and phosphorylated tau, were not significantly correlated with the annual decrement of adaptive behavior scores after age-adjustment. These results suggest that plasma NfL has the potential to serve as an objective biomarker to predict dementia in adult DS patients.

Plasma biomarkers for amyloid, tau, and cytokines in Down syndrome and sporadic Alzheimer's disease

BACKGROUND

Down syndrome (DS), caused by chromosome 21 trisomy, is associated with an ultra-high risk of dementia due to Alzheimer's disease (AD), driven by amyloid precursor protein (APP) gene triplication. Understanding relevant molecular differences between those with DS, those with sporadic AD (sAD) without DS, and controls will aid in understanding AD development in DS. We explored group differences in plasma concentrations of amyloid-β peptides and tau (as their accumulation is a characteristic feature of AD) and cytokines (as the inflammatory response has been implicated in AD development, and immune dysfunction is common in DS).

METHODS

We used ultrasensitive assays to compare plasma concentrations of the amyloid-β peptides Aβ40 and Aβ42, total tau (t-tau), and the cytokines IL1β, IL10, IL6, and TNFα between adults with DS (n = 31), adults with sAD (n = 27), and controls age-matched to the group with DS (n = 27), and explored relationships between molecular concentrations and with age within each group. In the group with DS, we also explored relationships with neurofilament light (NfL) concentration, due to its potential use as a biomarker for AD in DS.

RESULTS

Aβ40, Aβ42, and IL1β concentrations were higher in DS, with a higher Aβ42/Aβ40 ratio in controls. The group with DS showed moderate positive associations between concentrations of t-tau and both Aβ42 and IL1β. Only NfL concentration in the group with DS showed a significant positive association with age.

CONCLUSIONS

Concentrations of Aβ40 and Aβ42 were much higher in adults with DS than in other groups, reflecting APP gene triplication, while no difference in the Aβ42/Aβ40 ratio between those with DS and sAD may indicate similar processing and deposition of Aβ40 and Aβ42 in these groups. Higher concentrations of IL1β in DS may reflect an increased vulnerability to infections and/or an increased prevalence of autoimmune disorders, while the positive association between IL1β and t-tau in DS may indicate IL1β is associated with neurodegeneration. Finally, NfL concentration may be the most suitable biomarker for dementia progression in DS. The identification of such a biomarker is important to improve the detection of dementia and monitor its progression, and for designing clinical intervention studies.

Cognitive markers of preclinical and prodromal Alzheimer's disease in Down syndrome

INTRODUCTION

Down syndrome (DS) is associated with an almost universal development of Alzheimer's disease. Individuals with DS are therefore an important population for randomized controlled trials to prevent or delay cognitive decline, though it is essential to understand the time course of early cognitive changes.

METHODS

We conducted the largest cognitive study to date with 312 adults with DS to assess age-related and Alzheimer's disease-related cognitive changes during progression from preclinical to prodromal dementia, and prodromal to clinical dementia.

RESULTS

Changes in memory and attention measures were most sensitive to early decline. Resulting sample size calculations for randomized controlled trials to detect significant treatment effects to delay decline were modest.

DISCUSSION

Our findings address uncertainties around the development of randomized controlled trials to delay cognitive decline in DS. Such trials are essential to reduce the high burden of dementia in people with DS and could serve as proof-of-principle trials for some drug targets.

Comparison of Receptive Verbal Abilities Assessed Using the KBIT-2 and BPVS3 in Adults With Down Syndrome

Down syndrome (DS) is the most common genetic cause of intellectual disability. There is, however, considerable variation in cognitive abilities between those with DS, with some individuals scoring at floor on some tests, particularly for age-standardised outcomes. This variation and these floor effects can pose a problem for comparing and combining study populations when different standardised measures have been used to assess individuals' cognitive abilities, for example combining results across studies to investigate genetic or other factors associated with cognitive abilities. To facilitate this comparison and combination of study populations assessed using different tests of verbal abilities, we administered two commonly used standardised tests of receptive language, the Kaufmann Brief Intelligence Test 2 (KBIT-2) verbal scale and the British Picture Vocabulary Scale 3 (BPVS3) to 34 adults with DS (age range 19-59) to investigate relationships between outcomes for these two tests. We found a very strong correlation between raw scores for the KBIT-2 verbal scale and the BPVS3, and determined equations to convert between scores for the two tests. Intraclass correlations between the two scales for age-equivalents and calculated z scores relative to population norms were also strong, though scores for both outcomes were significantly higher for the KBIT-2 verbal scale compared to the BPVS3. This deviation in scores between the two tests was greater as z scores decreased for both tests (i.e., for lower scoring individuals), with no such relationship observed for age-equivalents. These results indicate the conversion of raw scores between the KBIT-2 verbal scale and the BPVS3 may be a more valid method for the comparison or combination of study samples with DS compared to the use of standardised scores. Such comparisons or combinations will aid our understanding of cognitive variations and factors associated with these variations within the population with DS.

Validating the Cognitive Scale for Down Syndrome (CS-DS) to Detect Longitudinal Cognitive Decline in Adults With Down Syndrome

Down syndrome (DS) is associated with intellectual disability and an ultra-high risk of developing dementia. Informant ratings are invaluable to assess abilities and related changes in adults with DS, particularly for those with more severe intellectual disabilities and/or cognitive decline. We previously developed the informant rated Cognitive Scale for Down Syndrome (CS-DS) to measure everyday cognitive abilities across memory, executive function, and language domains in adults with DS, finding CS-DS scores are a valid measure of general abilities, and are significantly lower for those with noticeable cognitive decline compared to those without decline. To further test the validity of the CS-DS in detecting changes associated with cognitive decline we collected longitudinal data across two time points, approximately 1.5-2 years apart, for 48 adults with DS aged 36 years and over. CS-DS total scores (78.83 ± 23.85 vs. 73.83 ± 25.35, p = 0.042) and executive function scores (46.40 ± 13.59 vs. 43.54 ± 13.60, p = 0.048) significantly decreased between the two time points, with scores in the memory domain trending towards a significant decrease (22.19 ± 8.03 vs. 20.81 ± 8.63, p = 0.064). Adults with noticeable cognitive decline at follow-up showed a trend to significantly greater change in total scores (7.81 ± 16.41 vs. 3.59 ± 16.79, p = 0.067) and significantly greater change in executive function scores (5.13 ± 9.22 vs. 1.72 ± 9.97, p = 0.028) compared to those without decline. Change in total scores showed significant correlations with change in scores from other informant measures of everyday adaptive abilities and symptoms associated with dementia, and participant assessment of general cognitive abilities (all p < 0.005), while change in memory scores (R ² = 0.28, p = 0.001) better predicted change in participant cognitive assessment scores than change in executive function (R ² = 0.15, p = 0.016) or language (R ² = 0.15, p = 0.018) scores. These results suggest informants may better detect changes in the executive function domain, while change in informant rated memory scores best predicts change in assessed cognitive ability. Alternatively, memory domain scores may be sensitive to changes across both early and late cognitive decline, whereas executive function domain scores are more sensitive to changes associated with later noticeable cognitive decline. Our results provide further support for the validity of the CS-DS to assess everyday cognitive abilities and to detect associated longitudinal changes in individuals with DS.

Striking reduction in neurons and glial cells in anterior thalamic nuclei of older patients with Down syndrome

The anterior thalamic nuclei are important for spatial and episodic memory, however, surprisingly little is known about the status of these nuclei in neurological conditions that present with memory impairments, such as Down syndrome. We quantified neurons and glial cells in the anterior thalamic nuclei of four older patients with Down syndrome. There was a striking reduction in the volume of the anterior thalamic nuclei and this appeared to reflect the loss of approximately 70% of neurons. The number of glial cells was also reduced but to a lesser degree than neurons. The anterior thalamic nuclei appear to be particularly sensitive to effects of aging in Down syndrome and the pathology in this region likely contributes to the memory impairments observed. These findings reaffirm the importance of examining the status of the anterior thalamic nuclei in conditions where memory impairments have been principally assigned to pathology in the medial temporal lobe.

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Volume of anterior thalamus is markedly reduced in older patients with Down syndrome.

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Number of neurons in anterior thalamus are substantially reduced.

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Number of glial cells in anterior thalamus are substantially reduced.

The impact of trisomy 21 on treatment modalities and outcome in adults with congenital heart disease in Switzerland

Trisomy 21 (T21) is associated in 40-45% of cases with heart defects, most commonly shunt lesions. These defects, if not repaired, can lead to irreversible shunt-induced pulmonary hypertension (i.e. Eisenmenger syndrome [ES]). In ES patients, intracardiac repair is no longer possible, but selective pulmonary vasodilators may increase exercise capacity and improve prognosis. This study aimed to estimate the prevalence of cardiac defects and ES in adult T21 patients and to assess the impact of T21 on treatment modalities and outcome in ES patients. A questionnaire was sent to 6906 Swiss physicians inviting them to indicate the number of adults with T21 under their care (survey report). We also analyzed all adults with ES (with and without T21) included in the Swiss Adult Congenital HEart disease Registry (SACHER) and studied the impact of T21 on the use of selective pulmonary vasodilators and survival. In the survey, 348 physicians cared for 695 adult T21 patients. Overall, 24% of T21 survey patients were known to have a cardiac defect, one in four with a defect had developed ES and 13% of those with ES were on specific pulmonary vasodilators. In SACHER, ES was present in 2% of adults with congenital heart disease and selective pulmonary vasodilators were used in 68% of ES patients with T21. In SACHER, survival during follow-up was worse with higher nt-proBNP levels (hazard ratio [HR] = 1.15 per 1000 units, 95% confidence interval [CI] = 1.02-1.29) and lower left ventricular ejection fraction (HR = 1.07 per percent decrease, 95% CI = 1.01-1.13). Age at inclusion and T21 did not affect survival. The prevalence of cardiac defects in adults with T21 in Switzerland is half the prevalence in children. T21 is over-represented among adults with ES. Raised awareness of the therapeutic options for T21 patients with ES is warranted.

Chromosomal disorders: estimating baseline birth prevalence and pregnancy outcomes worldwide

Chromosomal disorders, of which Down syndrome is the most common, can cause multi-domain disability. In addition, compared to the general population, there is a higher frequency of death before the age of five. In many settings, large gaps in data availability have hampered policy-making, programme priorities and resource allocation for these important conditions. We have developed methods, which overcome this lack of data and allow estimation of the burden of affected pregnancies and their outcomes in different settings worldwide. For example, the methods include a simple equation relating the percentage of mothers 35 and over to Down syndrome birth prevalence. The results obtained provide a starting point for consideration of services that can be implemented for the care and prevention of these disorders.

Trisomy of human chromosome 21 enhances amyloid-β deposition independently of an extra copy of APP

Down syndrome, caused by trisomy of chromosome 21, is the single most common risk factor for early-onset Alzheimer's disease. Worldwide approximately 6 million people have Down syndrome, and all these individuals will develop the hallmark amyloid plaques and neurofibrillary tangles of Alzheimer's disease by the age of 40 and the vast majority will go on to develop dementia. Triplication of APP, a gene on chromosome 21, is sufficient to cause early-onset Alzheimer's disease in the absence of Down syndrome. However, whether triplication of other chromosome 21 genes influences disease pathogenesis in the context of Down syndrome is unclear. Here we show, in a mouse model, that triplication of chromosome 21 genes other than APP increases amyloid-β aggregation, deposition of amyloid-β plaques and worsens associated cognitive deficits. This indicates that triplication of chromosome 21 genes other than APP is likely to have an important role to play in Alzheimer's disease pathogenesis in individuals who have Down syndrome. We go on to show that the effect of trisomy of chromosome 21 on amyloid-β aggregation correlates with an unexpected shift in soluble amyloid-β 40/42 ratio. This alteration in amyloid-β isoform ratio occurs independently of a change in the carboxypeptidase activity of the γ-secretase complex, which cleaves the peptide from APP, or the rate of extracellular clearance of amyloid-β. These new mechanistic insights into the role of triplication of genes on chromosome 21, other than APP, in the development of Alzheimer's disease in individuals who have Down syndrome may have implications for the treatment of this common cause of neurodegeneration.

Aging With Down Syndrome: The Dual Diagnosis: Alzheimer's Disease and Down Syndrome

BACKGROUND

People with Down syndrome (DS) enjoy a longer life expectancy now than they ever have before and are therefore at greater risk of developing conditions associated with aging, including dementia.

OBJECTIVES

To explore the phenomenon of dementia in DS.

METHODS

Medline and Google Scholar searches were conducted for relevant articles, chapters, and books published until 2017. Search terms included Alzheimer's disease, cognitive impairment, dementia, DS, and trisomy 21. Publications found through this indexed search were reviewed for further references.

RESULTS AND CONCLUSIONS

Virtually, all subject aged 35 to 40 show key neuropathologic changes characteristic of Alzheimer's disease, but only a part of them show clinical signs of dementia, usually around the age of 50 years. Early signs of dementia in people with DS may be different from those experienced by the general population. Failure to recognize this can delay diagnosis and subsequent interventions.

Projected number of children with isolated spina bifida or down syndrome in England and Wales by 2020

Children with major congenital anomalies often require lifelong access to health and social care services. Estimating future numbers of affected individuals can aid health and social care planning. This study aimed to estimate the number of children aged 0-15 years living with spina bifida or Down syndrome in England and Wales by 2020. Cases of spina bifida and Down syndrome born during 1998-2013 were identified from the Northern Congenital Abnormality Survey and the National Down Syndrome Cytogenetic Register, respectively. The number of infants born with spina bifida during 1998-2019 were estimated by applying the average prevalence rate in the North of England to actual and projected births in England and Wales. Poisson regression was performed to estimate the number of infants born with Down syndrome in England and Wales during 1998-2013 and 2004-2019. The numbers of children aged 0-15 living with spina bifida or Down syndrome in 2014 and in 2020 were then estimated by multiplying year- and age-specific survival estimates by the number of affected births. An estimated 956 children with isolated spina bifida, 623 children with spina bifida and hydrocephalus and 11,592 children with Down syndrome aged 0-15 years will be living in England and Wales by 2020, increases of 7.2%, 12.0% and 12.7% since 2014, respectively. Due to improvements in survival, an increase in population size and changes in maternal age distribution at delivery, we anticipate further increases in the number of children living with spina bifida or Down syndrome by 2020.

Down syndrome, beta-amyloid and neuroimaging

This review focuses on the role of Aβ in AD pathogenesis in Down syndrome and current approaches for imaging Aβ in vivo. We will describe how Aβ deposits with age, the posttranslational modifications that can occur, and detection in biofluids. Three unique case studies describing partial trisomy 21 cases without APP triplication, and the occurrences of low level mosaic trisomy 21 in an early onset AD patient are presented. Brain imaging for Aβ includes those by positron emission tomography and ligands (Pittsburgh Compound B, Florbetapir, and FDDNP) that bind Aβ have been published and are summarized here. In combination, we have learned a great deal about Aβ in DS in terms of characterizing age of onset of this pathology and it is exciting to note that there is a clinical trial in DS targeting Aβ that may lead to clinical benefits.

A third copy of the Down syndrome cell adhesion molecule (Dscam) causes synaptic and locomotor dysfunction in Drosophila

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

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Drosophila expressing a third copy of Dscam have altered neuromuscular transmission.

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Drosophila expressing a third copy of Dscam have deficits in locomotor coordination.

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Drosophila are a powerful system for studying single-gene effects in Down syndrome.

Genomics-based non-invasive prenatal testing for detection of fetal chromosomal aneuploidy in pregnant women

BACKGROUND

Common fetal aneuploidies include Down syndrome (trisomy 21 or T21), Edward syndrome (trisomy 18 or T18), Patau syndrome (trisomy 13 or T13), Turner syndrome (45,X), Klinefelter syndrome (47,XXY), Triple X syndrome (47,XXX) and 47,XYY syndrome (47,XYY). Prenatal screening for fetal aneuploidies is standard care in many countries, but current biochemical and ultrasound tests have high false negative and false positive rates. The discovery of fetal circulating cell-free DNA (ccfDNA) in maternal blood offers the potential for genomics-based non-invasive prenatal testing (gNIPT) as a more accurate screening method. Two approaches used for gNIPT are massively parallel shotgun sequencing (MPSS) and targeted massively parallel sequencing (TMPS).

OBJECTIVES

To evaluate and compare the diagnostic accuracy of MPSS and TMPS for gNIPT as a first-tier test in unselected populations of pregnant women undergoing aneuploidy screening or as a second-tier test in pregnant women considered to be high risk after first-tier screening for common fetal aneuploidies. The gNIPT results were confirmed by a reference standard such as fetal karyotype or neonatal clinical examination.

SEARCH METHODS

We searched 13 databases (including MEDLINE, Embase and Web of Science) from 1 January 2007 to 12 July 2016 without any language, search filter or publication type restrictions. We also screened reference lists of relevant full-text articles, websites of private prenatal diagnosis companies and conference abstracts.

SELECTION CRITERIA

Studies could include pregnant women of any age, ethnicity and gestational age with singleton or multifetal pregnancy. The women must have had a screening test for fetal aneuploidy by MPSS or TMPS and a reference standard such as fetal karyotype or medical records from birth.

DATA COLLECTION AND ANALYSIS

Two review authors independently carried out study selection, data extraction and quality assessment (using the QUADAS-2 tool). Where possible, hierarchical models or simpler alternatives were used for meta-analysis.

MAIN RESULTS

Sixty-five studies of 86,139 pregnant women (3141 aneuploids and 82,998 euploids) were included. No study was judged to be at low risk of bias across the four domains of the QUADAS-2 tool but applicability concerns were generally low. Of the 65 studies, 42 enrolled pregnant women at high risk, five recruited an unselected population and 18 recruited cohorts with a mix of prior risk of fetal aneuploidy. Among the 65 studies, 44 evaluated MPSS and 21 evaluated TMPS; of these, five studies also compared gNIPT with a traditional screening test (biochemical, ultrasound or both). Forty-six out of 65 studies (71%) reported gNIPT assay failure rate, which ranged between 0% and 25% for MPSS, and between 0.8% and 7.5% for TMPS.In the population of unselected pregnant women, MPSS was evaluated by only one study; the study assessed T21, T18 and T13. TMPS was assessed for T21 in four studies involving unselected cohorts; three of the studies also assessed T18 and 13. In pooled analyses (88 T21 cases, 22 T18 cases, eight T13 cases and 20,649 unaffected pregnancies (non T21, T18 and T13)), the clinical sensitivity (95% confidence interval (CI)) of TMPS was 99.2% (78.2% to 100%), 90.9% (70.0% to 97.7%) and 65.1% (9.16% to 97.2%) for T21, T18 and T13, respectively. The corresponding clinical specificity was above 99.9% for T21, T18 and T13.In high-risk populations, MPSS was assessed for T21, T18, T13 and 45,X in 30, 28, 20 and 12 studies, respectively. In pooled analyses (1048 T21 cases, 332 T18 cases, 128 T13 cases and 15,797 unaffected pregnancies), the clinical sensitivity (95% confidence interval (CI)) of MPSS was 99.7% (98.0% to 100%), 97.8% (92.5% to 99.4%), 95.8% (86.1% to 98.9%) and 91.7% (78.3% to 97.1%) for T21, T18, T13 and 45,X, respectively. The corresponding clinical specificities (95% CI) were 99.9% (99.8% to 100%), 99.9% (99.8% to 100%), 99.8% (99.8% to 99.9%) and 99.6% (98.9% to 99.8%). In this risk group, TMPS was assessed for T21, T18, T13 and 45,X in six, five, two and four studies. In pooled analyses (246 T21 cases, 112 T18 cases, 20 T13 cases and 4282 unaffected pregnancies), the clinical sensitivity (95% CI) of TMPS was 99.2% (96.8% to 99.8%), 98.2% (93.1% to 99.6%), 100% (83.9% to 100%) and 92.4% (84.1% to 96.5%) for T21, T18, T13 and 45,X respectively. The clinical specificities were above 100% for T21, T18 and T13 and 99.8% (98.3% to 100%) for 45,X. Indirect comparisons of MPSS and TMPS for T21, T18 and 45,X showed no statistical difference in clinical sensitivity, clinical specificity or both. Due to limited data, comparative meta-analysis of MPSS and TMPS was not possible for T13.We were unable to perform meta-analyses of gNIPT for 47,XXX, 47,XXY and 47,XYY because there were very few or no studies in one or more risk groups.

AUTHORS' CONCLUSIONS

These results show that MPSS and TMPS perform similarly in terms of clinical sensitivity and specificity for the detection of fetal T31, T18, T13 and sex chromosome aneuploidy (SCA). However, no study compared the two approaches head-to-head in the same cohort of patients. The accuracy of gNIPT as a prenatal screening test has been mainly evaluated as a second-tier screening test to identify pregnancies at very low risk of fetal aneuploidies (T21, T18 and T13), thus avoiding invasive procedures. Genomics-based non-invasive prenatal testing methods appear to be sensitive and highly specific for detection of fetal trisomies 21, 18 and 13 in high-risk populations. There is paucity of data on the accuracy of gNIPT as a first-tier aneuploidy screening test in a population of unselected pregnant women. With respect to the replacement of invasive tests, the performance of gNIPT observed in this review is not sufficient to replace current invasive diagnostic tests.We conclude that given the current data on the performance of gNIPT, invasive fetal karyotyping is still the required diagnostic approach to confirm the presence of a chromosomal abnormality prior to making irreversible decisions relative to the pregnancy outcome. However, most of the gNIPT studies were prone to bias, especially in terms of the selection of participants.

Screening for glucose intolerance and development of a lifestyle education programme for prevention of type 2 diabetes in a population with intellectual disabilities: the STOP Diabetes research project

Background

The prevalence of type 2 diabetes mellitus (T2DM) and of cardiovascular disease (CVD) is believed to be higher among people with intellectual disability (ID) than in the general population. However, research on prevalence and prevention in this population is limited.

Objectives

The objectives of this programme of work were to establish a programme of research that would significantly enhance the knowledge and understanding of impaired glucose regulation (IGR) and T2DM in people with ID; to test strategies for the early identification of IGR and T2DM in people with ID; and to develop a lifestyle education programme and educator training protocol to promote behaviour change in a population with ID and IGR (or at a high risk of T2DM/CVD).

Setting

Leicestershire, UK.

Participants

Adults with ID were recruited from community settings, including residential homes and family homes. Adults with mild to moderate ID who had an elevated body mass index (BMI) of ≥ 25 kg/m2and/or IGR were invited to take part in the education programme.

Main outcome measures

The primary outcome of the screening programme was the prevalence of screen-detected T2DM and IGR. The uptake, feasibility and acceptability of the intervention were assessed.

Data sources

Participants were recruited from general practices, specialist ID services and clinics, and through direct contact.

Results

A total of 930 people with ID were recruited to the screening programme: 58% were male, 80% were white and 68% were overweight or obese. The mean age of participants was 43.3 years (standard deviation 14.2 years). Bloods were obtained for 675 participants (73%). The prevalence of previously undiagnosed T2DM was 1.3% [95% confidence interval (CI) 0.5% to 2%] and of IGR was 5% (95% CI 4% to 7%). Abnormal IGR was more common in those of non-white ethnicity; those with a first-degree family history of diabetes; those with increasing weight, waist circumference, BMI, diastolic blood pressure or triglycerides; and those with lower high-density lipoprotein cholesterol. We developed a lifestyle educational programme for people with ID, informed by findings from qualitative stakeholder interviews (health-care professionals,n = 14; people with ID,n = 7) and evidence reviews. Subsequently, 11 people with ID (and carers) participated in pilot education sessions (two groups) and five people attended education for the feasibility stage (one group). We found that it was feasible to collect primary outcome measures on physical activity and sedentary behaviour using wrist-worn accelerometers. We found that the programme was relatively costly, meaning that large changes in activity or diet (or a reduction in programme costs) would be necessary for the programme to be cost-effective. We also developed a quality development process for assessing intervention fidelity.

Limitations

We were able to screen only around 30% of the population and involved only a small number in the piloting and feasibility work.

Conclusions

The results from this programme of work have significantly enhanced the existing knowledge and understanding of T2DM and IGR in people with ID. We have developed a lifestyle education programme and educator training protocol to promote behaviour change in this population.

Future work

Further work is needed to evaluate the STOP Diabetes intervention to identify cost-effective strategies for its implementation.

Trial registration

ClinicalTrials.gov NCT02513277.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme and will be published in full inHealth Research Programme Grants for Applied Research; Vol. 5, No. 11. See the NIHR Journals Library website for further project information.

Obstructive sleep apnoea/hypopnoea syndrome in adults with Down syndrome

Key points

Educational aims

Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is characterised by repeated cycles of upper airway obstruction during sleep, leading to diurnal symptoms. Individuals with Down syndrome are predisposed to OSAHS due to overlap between the Down syndrome phenotype and OSAHS risk factors. Recent large studies using subjective and objective measures estimate that OSAHS affects around 40% of adults with Down syndrome, in contrast to 2–4% of the general adult population. The “double-hit” of comorbid Down syndrome and OSAHS may accelerate cognitive decline in adults with Down syndrome. However, with the appropriate care and support, OSAHS can be treated effectively in this group using continuous positive airway pressure (CPAP) therapy, improving daytime function and behaviour. Symptoms of OSAHS should be routinely monitored in this population, with testing and treatment available to all adults with Down syndrome; however, this is not currently commonplace, and health inequalities are evident.

Obstructive sleep apnoea/hypopnoea syndrome affects ∼40% of adults with Down syndrome cut can be treated effectivelyhttp://ow.ly/Jdco3062xP5