Autoimmunity in Down's syndrome via cytokines, CD4 T cells and CD11c+ B cells.

Down's syndrome (DS) presents with a constellation of cardiac, neurocognitive and growth impairments. Individuals with DS are also prone to severe infections and autoimmunity including thyroiditis, type 1 diabetes, coeliac disease and alopecia areata1,2. Here, to investigate the mechanisms underlying autoimmune susceptibility, we mapped the soluble and cellular immune landscape of individuals with DS. We found a persistent elevation of up to 22 cytokines at steady state (at levels often exceeding those in patients with acute infection) and detected basal cellular activation: chronic IL-6 signalling in CD4 T cells and a high proportion of plasmablasts and CD11c+TbethighCD21low B cells (Tbet is also known as TBX21). This subset is known to be autoimmune-prone and displayed even greater autoreactive features in DS including receptors with fewer non-reference nucleotides and higher IGHV4-34 utilization. In vitro, incubation of naive B cells in the plasma of individuals with DS or with IL-6-activated T cells resulted in increased plasmablast differentiation compared with control plasma or unstimulated T cells, respectively. Finally, we detected 365 auto-antibodies in the plasma of individuals with DS, which targeted the gastrointestinal tract, the pancreas, the thyroid, the central nervous system, and the immune system itself. Together, these data point to an autoimmunity-prone state in DS, in which a steady-state cytokinopathy, hyperactivated CD4 T cells and ongoing B cell activation all contribute to a breach in immune tolerance. Our findings also open therapeutic paths, as we demonstrate that T cell activation is resolved not only with broad immunosuppressants such as Jak inhibitors, but also with the more tailored approach of IL-6 inhibition.

A landmark-free morphometrics pipeline for high-resolution phenotyping: application to a mouse model of Down syndrome.

Characterising phenotypes often requires quantification of anatomical shape. Quantitative shape comparison (morphometrics) traditionally uses manually located landmarks and is limited by landmark number and operator accuracy. Here, we apply a landmark-free method to characterise the craniofacial skeletal phenotype of the Dp1Tyb mouse model of Down syndrome and a population of the Diversity Outbred (DO) mouse model, comparing it with a landmark-based approach. We identified cranial dysmorphologies in Dp1Tyb mice, especially smaller size and brachycephaly (front-back shortening), homologous to the human phenotype. Shape variation in the DO mice was partly attributable to allometry (size-dependent shape variation) and sexual dimorphism. The landmark-free method performed as well as, or better than, the landmark-based method but was less labour-intensive, required less user training and, uniquely, enabled fine mapping of local differences as planar expansion or shrinkage. Its higher resolution pinpointed reductions in interior mid-snout structures and occipital bones in both the models that were not otherwise apparent. We propose that this landmark-free pipeline could make morphometrics widely accessible beyond its traditional niches in zoology and palaeontology, especially in characterising developmental mutant phenotypes.

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.

Why do individuals with Williams syndrome or Down syndrome fail the Weather Prediction Task?

Williams syndrome (WS) and Down syndrome (DS) are two neurodevelopmental disorders with distinct genetic origins characterized by mild to moderate intellectual disability. Individuals with WS or DS exhibit impaired hippocampus-dependent place learning and enhanced striatum-dependent spatial response learning. Here, we used the Weather Prediction Task (WPT), which can be solved using hippocampus- or striatum-dependent learning strategies, to determine whether individuals with WS or DS exhibit similar profiles outside the spatial domain. Only 10% of individuals with WS or DS solved the WPT. We further assessed whether a concurrent memory task could promote reliance on procedural learning to solve the WPT in individuals with WS but found that the concurrent task did not improve performance. To understand how the probabilistic cue-outcome associations influences WPT performance, and whether individuals with WS or DS can ignore distractors, we assessed performance using a visual learning task with differing reward contingencies, and a modified WPT with unpredictive cues. Both probabilistic feedback and distractors negatively impacted the performance of individuals with WS or DS. These findings are consistent with deficits in hippocampus-dependent learning and executive functions, and reveal the importance of congruent feedback and the minimization of distractors to optimize learning in these two populations.

Effects of a 12-week telehealth exercise intervention on gait speed and gait deviations in adults with Down syndrome.

BACKGROUND: Altered gait patterns and reduced walking speed are commonly reported in adults with Down syndrome (DS). Research on the effects of DS-specific exercise programmes on adults with DS is lacking. The purpose of this quasi-experimental study was to evaluate the changes in gait deviations and walking speed in adults with DS after a DS-specific exercise programme. METHODS: Twenty participants underwent a 12-week, DS-specific exercise programme in a telehealth format. Before and after the intervention, gait deviations were assessed with the Ranchos Los Amigos Observational Gait Analysis form, and comfortable walking speed was evaluated with the 4-m walk test. RESULTS: We observed increased comfortable walking speed and reduced gait deviations in the whole gait cycle in adults with DS after the intervention. There were fewer gait deviations during single-leg stance and swing-limb advancement and at the hip, knee and ankle joints after the 12-week exercise programme. CONCLUSIONS: Gait speed and observable gait impairments in adults with DS significantly improved following a 12-week telehealth exercise programme.

Prefrontal-hippocampal functional connectivity encodes recognition memory and is impaired in intellectual disability.

Down syndrome (DS) is the most common form of intellectual disability. The cognitive alterations in DS are thought to depend on brain regions critical for learning and memory such as the prefrontal cortex (PFC) and the hippocampus (HPC). Neuroimaging studies suggest that increased brain connectivity correlates with lower intelligence quotients (IQ) in individuals with DS; however, its contribution to cognitive impairment is unresolved. We recorded neural activity in the PFC and HPC of the trisomic Ts65Dn mouse model of DS during quiet wakefulness, natural sleep, and the performance of a memory test. During rest, trisomic mice showed increased theta oscillations and cross-frequency coupling in the PFC and HPC while prefrontal-hippocampal synchronization was strengthened, suggesting hypersynchronous local and cross-regional processing. During sleep, slow waves were reduced, and gamma oscillations amplified in Ts65Dn mice, likely reflecting prolonged light sleep. Moreover, hippocampal sharp-wave ripples were disrupted, which may have further contributed to deficient memory consolidation. Memory performance in euploid mice correlated strongly with functional connectivity measures that indicated a hippocampal control over memory acquisition and retrieval at theta and gamma frequencies, respectively. By contrast, trisomic mice exhibited poor memory abilities and disordered prefrontal-hippocampal functional connectivity. Memory performance and key neurophysiological alterations were rescued after 1 month of chronic administration of a green tea extract containing epigallocatequin-3-gallate (EGCG), which improves executive function in young adults with DS and Ts65Dn mice. Our findings suggest that abnormal prefrontal-hippocampal circuit dynamics are candidate neural mechanisms for memory impairment in DS.

Obstructive sleep apneas naturally occur in mice during REM sleep and are highly prevalent in a mouse model of Down syndrome.

STUDY OBJECTIVES: The use of mouse models in sleep apnea study is limited by the belief that central (CSA) but not obstructive sleep apneas (OSA) occur in rodents. We aimed to develop a protocol to investigate the presence of OSAs in wild-type mice and, then, to apply it to a validated model of Down syndrome (Ts65Dn), a human pathology characterized by a high incidence of OSAs. METHODS: In a pilot study, nine C57BL/6J wild-type mice were implanted with electrodes for electroencephalography (EEG), neck electromyography (nEMG), and diaphragmatic activity (DIA), and then placed in a whole-body-plethysmographic (WBP) chamber for 8 h during the rest (light) phase to simultaneously record sleep and breathing activity. CSA and OSA were discriminated on the basis of WBP and DIA signals recorded simultaneously. The same protocol was then applied to 12 Ts65Dn mice and 14 euploid controls. RESULTS: OSAs represented about half of the apneic events recorded during rapid-eye-movement-sleep (REMS) in each experimental group, while the majority of CSAs were found during non-rapid eye movement sleep. Compared with euploid controls, Ts65Dn mice had a similar total occurrence rate of apneic events during sleep, but a significantly higher occurrence rate of OSAs during REMS, and a significantly lower occurrence rate of CSAs during NREMS. CONCLUSIONS: Mice physiologically exhibit both CSAs and OSAs. The latter appear almost exclusively during REMS, and are highly prevalent in Ts65Dn. Mice may, thus, represent a useful model to accelerate the understanding of the pathophysiology and genetics of sleep-disordered breathing and to help the development of new therapies.

Facial recognition accuracy in photographs of Thai neonates with Down syndrome among physicians and the Face2Gene application.

Down syndrome (DS) is typically recognizable in those who present with multiple dysmorphism, especially in regard to facial phenotypes. However, as the presentation of DS in neonates is less obvious, a phenotype-based presumptive diagnosis is more challenging. Recently, an artificial intelligence (AI) application, Face2Gene, was developed to help physicians recognize specific genetic syndromes by using two-dimensional facial photos. As of yet, there has not been any study comparing accuracy among physicians or applications. Our objective was to compare the facial recognition accuracy of DS in Thai neonates, using facial photographs, among physicians and the Face2Gene. Sixty-four Thai neonates at Thammasat University Hospital, with genetic testing and signed parental consent, were divided into a DS group (25) and non-DS group (39). Non-DS was further divided into unaffected (19) and those affected with other syndromes (20). Our results revealed physician accuracy (89%) was higher than the Face2Gene (81%); however, the application was higher in sensitivity (100%) than physicians (86%). While this application can serve as a helpful assistant in facilitating any genetic syndrome such as DS, to aid clinicians in recognizing DS facial features in neonates, it is not a replacement for well-trained doctors.

Delivering a new diagnosis of Down syndrome: Parent experience.

Down syndrome is one of the most common chromosomal abnormalities. In 2014, in conjunction with the passing of House Bill 552, the Ohio Department of Health released a Down syndrome fact sheet to be given to parents at time of diagnosis to answer basic questions regarding the diagnosis. Our survey helps us to understand parental experience in receiving a new Down syndrome diagnosis including information provided. An electronic survey was created and distributed to members of established Down syndrome parent groups in Ohio. Questions assessed the parental experience at the time of receiving a Down syndrome. We also looked at parent perceptions after the implementation of a Down syndrome fact sheet. Responses were collected regarding experience at the time of diagnosis and broadly categorized into a trichotomy of positive experience (>5), neutral experience (=5), and negative experience (<5). Parents report an overall negative experience when receiving a new diagnosis of Down syndrome (mean of 4 on scale of 0-10), which did not increase after 2014 (p >0.05). Eighty-five percent of parents with children born in 2014 or after report that they did not receive the Ohio Department of Health Down syndrome fact sheet. Legislation regarding a diagnosis of Down syndrome exists in 20 states with significant variability, readability of those fact sheets. Legislation requiring accurate information be given to families was not always followed, and printed literature alone did not correlate with improved parent experience; additional efforts are necessary to ensure that the experience receiving a diagnosis of Down syndrome is not a negative one.

Neonatal complications of Down syndrome and factors necessitating intensive care.

Limited knowledge exists about how frequently newborns with Down syndrome receive a prenatal diagnosis, require intensive care, and what surgical and medical factors are contributory. A retrospective cohort study was performed for patients with a diagnosis of Down syndrome born in 2013 and 2014 who sought care at Cincinnati Children's Hospital Medical Center during the first year of life. Data were extracted from the electronic medical record through the first year of life including need for intensive care as a newborn, prenatal diagnosis, and medical and surgical complications. Of the 129 patients in the study, 65% required intensive care as newborns. The presence of a structural abnormality that required surgical correction in the neonatal period and certain types of congenital heart disease not requiring surgical intervention in the neonatal period were positively associated with the need for intensive care. A minority of infants, 8%, had a confirmed prenatal diagnosis. A majority of newborns with Down syndrome required intensive care following birth while a minority had any concern for the diagnosis prenatally. Improving prenatal diagnostic rates would allow for better prenatal counseling and delivery planning, while targeting therapeutic interventions for this population is needed to improve outcomes.

Aberrant myelomonocytic CD56 expression in Down syndrome is frequent and not associated with leukemogenesis.

Children with Down syndrome (DS) are at an increased risk of developing transient abnormal myelopoiesis (TAM) and acute leukemia. Aberrant expression of CD56 has been observed on myeloid leukemic blasts in DS patients. In general, CD56 expression in acute myeloid leukemia (AML) is considered a promoter of leukemogenesis. We did a retrospective flow cytometric study to investigate mature myelomonocytic cell CD56 expression patterns in TAM, non-TAM, and leukemia cases with DS. Flow cytometric analysis showed that granulocyte and monocyte aberrant/dysplastic CD56 expression is an inherent characteristic of most DS patients irrespective of the presence of TAM or leukemia. Increased CD56 expression in monocyte and granulocyte populations in DS could be multifactorial; greater expression of RUNX1 secondary to the gene dose effect of trisomy 21 along with the maturational state of the cells are the potential contributors. Unlike AML seen in non-DS patients, CD56 overexpression in DS AML cases does not appear to play a role in leukemogenesis.

Children with Down syndrome and sleep disordered breathing have altered cardiovascular control.

BACKGROUND: Sleep disordered breathing (SDB) in typically developing (TD) children is associated with adverse cardiovascular effects. As children with Down syndrome (DS) are at increased risk for SDB, we aimed to compare the cardiovascular effects of SDB in children with DS to those of TD children with and without SDB. METHODS: Forty-four children with DS (3-19 years) were age and sex matched with 44 TD children without SDB (TD-) and with 44 TD children with matched severity of SDB (TD+). Power spectral density was calculated from ECG recordings, for low frequency (LF), high frequency (HF), total power and the LF/HF ratio. RESULTS: Children with DS had lower HF power, and higher LF/HF during sleep and when awake. There were no differences between groups for LF power. SpO2 nadir, average SpO2 drop and SpO2 > 4% drop were larger in the DS group compared to the TD+ group (p < 0.05 for all). CONCLUSIONS: Our findings demonstrate significantly reduced parasympathetic activity (reduced HF power) and increased LF/HF (a measure of sympathovagal balance) in children with DS, together with greater exposure to hypoxia, suggesting SDB has a greater effect in these children that may contribute to an increased risk of adverse cardiovascular outcomes. IMPACT: Sleep disordered breathing in children with Down syndrome exacerbates impaired autonomic control and increases exposure to hypoxia, compared to typically developing children. In typically developing children sleep disordered breathing has adverse effects on autonomic cardiovascular control. The prevalence of sleep disordered breathing is very high in children with Down syndrome; however, studies on the effects on cardiovascular control are limited in this population. This study supports screening and early treatment of sleep disordered breathing in children with Down syndrome.

The influence of sleep on language production modalities in preschool children with Down syndrome.

Evidence suggests that sleep may relate to oral language production in children with Down syndrome. However, these children are capable of using complex referential gestures as a compensation strategy for problems with oral production, and those with a greater productive oral vocabulary have less gestural vocabulary. The goal of this study was to explore whether sleep quality relates to oral and gestural production modalities in children with Down syndrome. We evaluated 36 preschool children with and without Down syndrome, paired by chronological age and gender, with similar sociodemographic backgrounds, using actigraphy to measure sleep behaviour and the Communicative Development Inventory for Down syndrome to measure vocabulary. Children with Down syndrome with better sleep efficiency showed more oral production but less gestural production. These results highlight the importance of sleep quality to language learning in children with Down syndrome.

A case of clubbed down syndrome in broilers.

This study presents a case of clubbed down syndrome in conventional broilers. During the first week of life, severe growth retardation was observed in approximately 25% of the flock. The growth-retarded chicks weighed only 45 g and showed a typical feather disorder which was most apparent on their abdomen and was defined in literature as typical for clubbed down syndrome. Necropsies, histology, biochemical analysis of blood and liver samples, serology and different PCR tests were performed in broilers to assess the aetiology of the clinical signs that were present in the affected broiler farm. Because of the suspicion of a possible link with the broiler-breeder farms, different investigations including serology, PCR and feed analysis were also performed on these farms. The results suggest that an accidentally excessive amount of calcium and iron in the feed of broiler-breeders, 3 weeks prior to first clinical signs in broilers, led to the development of clubbed down in the offspring, because of a relative Zn-deficiency in broiler-breeders and an absolute Zn-deficiency in the hatching eggs that were produced during this period. This appeared to be a reversible process as no clinical signs were observed in younger offspring of these broiler-breeders after they had consumed more of the new batch of feed. A potential involvement of Astrovirus could not be completely ruled out. This study demonstrates the importance of correct mineral concentrations in broiler-breeder feed and the impact it can have on the development of the offspring.

Functioning, participation, and quality of life in children with intellectual disability: an observational study.

AIMS: To investigate associations between functioning, community participation, and quality of life (QoL) and identify whether participation mediates the effects of functioning on QoL. METHOD: The caregivers of 435 children (211 females, 224 males; mean age 12y; SD 3y 11mo; age range 5-18y) with intellectual disability and autism spectrum disorder, cerebral palsy, Down syndrome, or Rett syndrome reported on their child's functioning (dependence for managing personal needs, mobility, communication, eye contact when speaking), frequency of participation, and QoL. Linear regression and mediation analyses were used to evaluate the relationships between child functioning, participation, and QoL. RESULTS: Children with greater dependency for managing personal needs and limited eye contact when speaking experienced poorer QoL. Less impaired functioning was associated with more frequent participation, which, in turn, was associated with a 3-point gain in QoL for each additional point in frequency of participation (coefficient=2.67, 95% confidence interval 1.56-3.78). The effect of impaired functioning on QoL was partially mediated by participation in children with greater dependency in managing personal needs and those with mildly impaired communication. INTERPRETATION: Greater levels of impairments with poorer functioning, notably a high level of dependence, were associated with poorer QoL. Poorer QoL can be partly explained by less frequent community participation.

SARS-CoV-2 Related Ischemic Colitis in an Adolescent With Trisomy 21: Diagnostic Pitfalls and Considerations.

Millions of patients seek medical attention for diarrhea, vomiting, nausea, and abdominal pain. In the current environment, it is important to recognize that these symptoms may be the only manifestation or may precede more serious systemic complications of COVID-19. Herein, we describe the first case of ischemic colitis (IC) in a young adult who presented with diarrhea and highlight the laboratory pitfalls for patients with COVID-19 presenting with gastrointestinal (GI) symptoms.

Current Analysis of Skeletal Phenotypes in Down Syndrome.

PURPOSE: Down syndrome (DS) is caused by trisomy 21 (Ts21) and results in skeletal deficits including shortened stature, low bone mineral density, and a predisposition to early onset osteoporosis. Ts21 causes significant alterations in skeletal development, morphology of the appendicular skeleton, bone homeostasis, age-related bone loss, and bone strength. However, the genetic or cellular origins of DS skeletal phenotypes remain unclear. RECENT FINDINGS: New studies reveal a sexual dimorphism in characteristics and onset of skeletal deficits that differ between DS and typically developing individuals. Age-related bone loss occurs earlier in the DS as compared to general population. Perturbations of DS skeletal quality arise from alterations in cellular and molecular pathways affected by the overexpression of trisomic genes. Sex-specific alterations occur in critical developmental pathways that disrupt bone accrual, remodeling, and homeostasis and are compounded by aging, resulting in increased risks for osteopenia, osteoporosis, and fracture in individuals with DS.

REM sleep in naps differentially relates to memory consolidation in typical preschoolers and children with Down syndrome.

Sleep is recognized as a physiological state associated with learning, with studies showing that knowledge acquisition improves with naps. Little work has examined sleep-dependent learning in people with developmental disorders, for whom sleep quality is often impaired. We examined the effect of natural, in-home naps on word learning in typical young children and children with Down syndrome (DS). Despite similar immediate memory retention, naps benefitted memory performance in typical children but hindered performance in children with DS, who retained less when tested after a nap, but were more accurate after a wake interval. These effects of napping persisted 24 h later in both groups, even after an intervening overnight period of sleep. During naps in typical children, memory retention for object-label associations correlated positively with percent of time in rapid eye movement (REM) sleep. However, in children with DS, a population with reduced REM, learning was impaired, but only after the nap. This finding shows that a nap can increase memory loss in a subpopulation, highlighting that naps are not universally beneficial. Further, in healthy preschooler's naps, processes in REM sleep may benefit learning.

Nerve growth factor (NGF) pathway biomarkers in Down syndrome prior to and after the onset of clinical Alzheimer's disease: A paired CSF and plasma study.

BACKGROUND: The discovery that nerve growth factor (NGF) metabolism is altered in Down syndrome (DS) and Alzheimer's disease (AD) brains offered a framework for the identification of novel biomarkers signalling NGF deregulation in AD pathology. METHODS: We examined levels of NGF pathway proteins (proNGF, neuroserpin, tissue plasminogen activator [tPA], and metalloproteases [MMP]) in matched cerebrospinal fluid (CSF)/plasma samples from AD-symptomatic (DSAD) and AD-asymptomatic (aDS) individuals with DS, as well as controls (HC). RESULTS: ProNGF and MMP-3 were elevated while tPA was decreased in plasma from individuals with DS. CSF from individuals with DS showed elevated proNGF, neuroserpin, MMP-3, and MMP-9. ProNGF and MMP-9 in CSF differentiated DSAD from aDS (area under the curve = 0.86, 0.87). NGF pathway markers associated with CSF amyloid beta and tau and differed by sex. DISCUSSION: Brain NGF metabolism changes can be monitored in plasma and CSF, supporting relevance in AD pathology. These markers could assist staging, subtyping, or precision medicine for AD in DS.

Adenovirus Infection in Children with Down Syndrome.

BACKGROUND: Adenovirus infections are prevalent in children. They usually cause a mild self-limited disease. However, this infection can be associated with considerable morbidity and mortality in specific populations, especially among immunocompromised children. Children with Down syndrome are susceptible to a higher frequency and increased severity of viral infections. Little is known about the severity and clinical course of adenovirus infections in children with Down syndrome. OBJECTIVES: To characterize hospitalized children diagnosed with Down syndrome and presenting with adenovirus infection. METHODS: We performed a retrospective review of children admitted with adenovirus from January 2005 to August 2014 from a single tertiary pediatric medical center in Israel. Data were compared between patients with and without Down syndrome. RESULTS: Among the 486 hospitalized children with adenoviral infection, 11 (2.28%) were diagnosed with Down syndrome. We found that children with Down syndrome were more likely to experience a higher incidence of complications (18.2% vs. 2.4%, P = 0.008), a higher rate of admissions to the intensive care unit (36.4% vs. 2.4%, P < 0.001), and more prolonged hospitalizations (17 ± 15.9 days compared to 4.46 ± 3.16, P = 0.025). CONCLUSIONS: Children with Down syndrome who were hospitalized with adenovirus infection represent a high-risk group and warrant close monitoring. If a vaccine for adenovirus becomes available, children with Down syndrome should be considered as candidates.