Motor, linguistic, personal and social aspects of children with Down syndrome

Pleiotropic effects of trisomy and pharmacologic modulation on structural, functional, molecular, and genetic systems in a Down syndrome mouse model

Down syndrome (DS) is characterized by skeletal and brain structural malformations, cognitive impairment, altered hippocampal metabolite concentration and gene expression imbalance. These alterations were usually investigated separately, and the potential rescuing effects of green tea extracts enriched in epigallocatechin-3-gallate (GTE-EGCG) provided disparate results due to different experimental conditions. We overcame these limitations by conducting the first longitudinal controlled experiment evaluating genotype and GTE-EGCG prenatal chronic treatment effects before and after treatment discontinuation. Our findings revealed that the Ts65Dn mouse model reflected the pleiotropic nature of DS, exhibiting brachycephalic skull, ventriculomegaly, neurodevelopmental delay, hyperactivity, and impaired memory robustness with altered hippocampal metabolite concentration and gene expression. GTE-EGCG treatment modulated most systems simultaneously but did not rescue DS phenotypes. On the contrary, the treatment exacerbated trisomic phenotypes including body weight, tibia microarchitecture, neurodevelopment, adult cognition, and metabolite concentration, not supporting the therapeutic use of GTE-EGCG as a prenatal chronic treatment. Our results highlight the importance of longitudinal experiments assessing the co-modulation of multiple systems throughout development when characterizing preclinical models in complex disorders and evaluating the pleiotropic effects and general safety of pharmacological treatments.

Participation, challenges and needs in children with down syndrome during cancer treatment at hospital: a qualitative study of parents' experiences

Background

Studies report that it can be challenging to assess and treat side-effects and symptoms among children who have impairments and difficulties in expressing their needs. Children with Down syndrome have an increased vulnerability and an increased risk for contracting leukaemia. There is sparse knowledge about the parental experience of how treatment and side-effects affect children with Down syndrome with leukaemia, as well as the role of participation during treatment.

Purpose

This study aimed to explore the perceptions of parents of children with Down syndrome and leukaemia regarding their child's treatment, side effects and participation during hospital care.

Methods

A qualitative study design was used, and interviews were conducted with a semi-structured interview-guide. Fourteen parents of 10 children with Down syndrome and acute lymphoblastic leukaemia from Sweden and Denmark, 1-18 years of age, participated. All children had completed therapy or had a few months left before the end of treatment. Data was analysed according to qualitative content analysis.

Results

Four sub-themes were identified: (1) Continuously dealing with the child's potential susceptibility; (2) Confidence and worries regarding decisions related to treatment regulation; (3) Challenges in communication, interpretation, and participation; and (4) Facilitating participation by adapting to the child's behavioural and cognitive needs. The sub-themes were bound together in an overarching theme, which expressed the core perception "Being the child's spokesperson to facilitate the child's participation during treatment". The parents expressed this role as self-evident to facilitate communication regarding the needs of the child, but also regarding how the cytotoxic treatment affected the vulnerable child. Parents conveyed the struggle to ensure the child's right to receive optimal treatment.

Conclusion

The study results highlight parental challenges regarding childhood disabilities and severe health conditions, as well as communication and ethical aspects regarding to act in the best interests of the child. Parents played a vital role in interpreting their child with Down syndrome. Involving parents during treatment enables a more accurate interpretation of symptoms and eases communication and participation. Still, the results raise questions regarding issues related to building trust in healthcare professionals in a context where medical, psychosocial and ethical dilemmas are present.

Therapeutic exercise to improve motor function among children with Down Syndrome aged 0 to 3 years: a systematic literature review and meta‑analysis

The effects and the prescription parameters of therapeutic exercise are not clear. For this reason, is needed to determine the effect of therapeutic exercises on the motor function of children with Down Syndrome (DS) aged 0 to 3 years. The present study is systematic review and meta-analysis of effectiveness outcomes in this population: gait, balance, motor development, fine motor skills, and executive functions. The databases of PubMed, PEDro, EMBASE, SCIELO, Lilacs, Cochrane library were searched from January to December 2019. We recruited Randomized Controlled Trials (RCTs) which met the inclusion criteria in our study. Six studies and 151 participants were included. Two types of therapeutic exercises, aerobic and neuromuscular, were identified. Both types of exercise were effective in improving outcomes. There were no differences between the modes of application of the exercise. No differences were identified between the treadmill and the physiotherapy plan for the reduction of the time to reach independent walking, Mean Difference (MD) 46.79, 95% Confidence Interval (IC) (- 32.60, 126.19), nor for the increase in walking speed MD 0.10 IC (- 0.02, 0.21) m/s. This study suggests that aerobic exercise therapy has a potentially effective role to promote the gait and motor development of children with DS aged 0 to 3 years when it is applied using a treadmill with a frequency of 5 days, a duration of 6-8 min, and an intensity of between 0.2 and 0.5 m/s. Studies with less heterogeneity and larger sample sizes are required.

Effects of Aquatic Training in Children with Autism Spectrum Disorder

Simple Summary

Swimming can be an alternative in the physical exercise curriculum to improve the motor abilities as well as the social behavior and communication skills of children with autism spectrum disorder (ASD) in schools and institutions. It is important to assess the effects of different forms of aquatic training (e.g., technical vs. game-based) to improve motor and stereotypy skills as well as emotion regulation in autistic children. This information should be of great interest to professionals to choose the appropriate training form to improve each of these abilities. The finding that both forms of swimming had a positive effect on gross motor skills and stereotyped behaviors in autistic children is in agreement with the accumulated evidence of swimming’s effectiveness to alleviate symptoms of motor and behavioral problems. In contrast, emotion regulation is not likely to improve after a short intervention period. The preliminary findings of this study are an important guidance for future researchers to further examine the neurophysiological and cognitive mechanisms of exercise–emotion and exercise–behavior relationships in children with ASD.

Abstract

A variety of aquatic training regimens have been found to be beneficial for individuals with autism spectrum disorders (ASD) in multiple domains. This study investigated and compared the efficacy of two aquatic training regimens (technical vs. game-based) on gross motor skills, stereotypy behavior and emotion regulation in children with ASD. Twenty-two autistic children were randomly assigned into three groups: two experimental groups performed either a technical aquatic program or a game-based aquatic program and a control group. Participants were assessed before and after an 8-week training period, with the Test of Gross Motor Development, the stereotypy subscale of the Gilliam Autism Rating Scale, and the Emotion Regulation Checklist. A significant effect for time was found in gross motor skills and stereotypy behavior in both experimental groups. An improvement in gross motor skills was observed in both experimental groups compared to the control group. A small pre-post change effect in emotion functioning was found in all groups. No significant differences were observed between the experimental groups in all assessed variables. Our findings provide additional evidence suggesting the effectiveness of beneficial effects of aquatic activities on the motor and social skills that underpin the hypothesis that motor and intellectual domains are highly interrelated in autistic children.

The Use of Virtual and Computational Technologies in the Psychomotor and Cognitive Development of Children with Down Syndrome: A Systematic Literature Review

Individuals with Down syndrome (DS) have numerous comorbidities due to trisomy 21. However, virtual reality-based therapy (VRT) has been used nowadays as a learning and visual motor tool in order to facilitate the development and learning process of this group. The aim of this article was to carry out an integrative review of the literature on the use of virtual and computational technologies in the stimulation of children with DS. A search was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) through single key words or their combinations using AND or OR operators: "Down syndrome" AND ("development" OR "cognition" OR "visomotor" OR "digital game" OR "virtual reality"). Eventually, 18 articles were included in our review. The games used in the research were able to stimulate, through the visual field, global motor skills, balance, body scheme and spatial organization, in addition to the learning of mathematical concepts, in order to directly influence the autonomous life activities, language skills, social skills and educational aspects of people with DS. Electronic games contribute to the teaching-learning relationship and stimulate neuropsychomotor and cognitive functions and development in children with DS.

Opportunities, barriers, and recommendations in down syndrome research

BACKGROUND

Recent advances in medical care have increased life expectancy and improved the quality of life for people with Down syndrome (DS). These advances are the result of both pre-clinical and clinical research but much about DS is still poorly understood. In 2020, the NIH announced their plan to update their DS research plan and requested input from the scientific and advocacy community.

OBJECTIVE

The National Down Syndrome Society (NDSS) and the LuMind IDSC Foundation worked together with scientific and medical experts to develop recommendations for the NIH research plan.

METHODS

NDSS and LuMind IDSC assembled over 50 experts across multiple disciplines and organized them in eleven working groups focused on specific issues for people with DS.

RESULTS

This review article summarizes the research gaps and recommendations that have the potential to improve the health and quality of life for people with DS within the next decade.

CONCLUSIONS

This review highlights many of the scientific gaps that exist in DS research. Based on these gaps, a multidisciplinary group of DS experts has made recommendations to advance DS research. This paper may also aid policymakers and the DS community to build a comprehensive national DS research strategy.

Delayed Diagnosis of Congenital Hypothyroidism in a Child with Trisomy 21 and Biotinidase Deficiency and Successful Use of Levothyroxine Sodium Oral Solution

Endocrine disorders are more common and appear earlier in people with trisomy 21 (T21) than in the general population, with thyroid dysfunction being the most common, including both congenital and acquired hypothyroidism. The treatment for biotinidase deficiency, a condition that occurs in approximately 1 : 110,000 people, is with biotin (vitamin B7) supplementation. However, biotin can interfere with endocrine laboratory assays and cause falsely low thyroid-stimulating hormone (TSH) and elevated free thyroxine (FT4) levels. This can interfere with the timely diagnosis and subsequent treatment of congenital hypothyroidism (CH). This case report describes an infant with partial biotinidase deficiency that was confirmed on day 10 of life. Routine screening erroneously reported "normal" TSH that caused delayed diagnosis of CH due to interference with the TSH assay from concurrent biotin use. Once the biotin treatment was withheld for 4 days and the thyroid function tests repeated, an elevated TSH became apparent. Treatment with tablet levothyroxine (L-T4) was started and subsequently changed to L-T4 oral solution (Tirosint®-SOL) to overcome treatment administration difficulties encountered with the tablet form. This resulted in improved TSH control due to more accurate and consistent dosing compared with the tablet formulation. This is the first report of the use of L-T4 oral solution in an infant with T21 and biotinidase deficiency.

Effects of Massage Therapy on the Development of Babies Born with Down Syndrome

Objective

To determine the short-term effects of infant massage on the development of Down syndrome babies.

Materials and Methods

The study compared two groups (intervention and control), each with 16 babies with Down syndrome between 4 and 8 months old. The variables developmental age and developmental quotient were measured at two distinct time points, at pretest and after 5 weeks, using the Brunet-Lézine Early Childhood Psychomotor Development revised scale. This scale measures the variables of age and development quotient in a partial way (motor, visual-motor coordination, language, and social development) and in a global way. The experimental group received infant massage, applied by the parents, during these 5 weeks, every day for at least 10 minutes. The massage protocol was based on the methodology created by Vimala McClure. The control group received it after 5 weeks.

Results

All developmental variables were improved in the experimental group but not in the control group. There were significant differences in developmental age between the two groups, and this outcome was better in the experimental group (p < 0.001). The 2-by-2 mixed-model analysis of variance indicates a statistically significant group-by-time interaction for all development quotients, both partial and global (p < 0.001), which was significantly higher in the experimental group than in the control group.

Conclusion

Infant massage therapy improves the development of babies with Down syndrome in the short term.

Systematic Review of the Main Motor Scales for Clinical Assessment of Individuals with down Syndrome

Objective: The aim of the present review was to identify the motor scales currently used to assess individuals with Down Syndrome (DS).Method: PubMed, WOS and BVS databases were systematically searched to identify the most relevant published studies that used motor scales in the evaluation of individuals with DS.Results: Of the 99 studies that met the eligibility criteria in this process, 20 experimental and observational studies were found to fully meet the eligibility criteria.Conclusion: We identified several motor scales including the Alberta Infant Motor Scale (AIMS), Test of Infant Motor Performance (TIMP), BAYLEY, Peabody Gross Motor Scale (PGMS-PDMS-GM), Gross Motor Function Measure (GMFM), Movement Assessment Battery for Children (MABC) and Pediatric Evaluation of Disability Inventory (PEDI).

Auditory-Perceptual Speech Features in Children With Down Syndrome

Speech disorders occur commonly in individuals with Down syndrome (DS), although data regarding the auditory-perceptual speech features are limited. This descriptive study assessed 47 perceptual speech features during connected speech samples in 26 children with DS. The most severely affected speech features were: naturalness, imprecise consonants, hyponasality, speech rate, inappropriate silences, irregular vowels, prolonged intervals, overall loudness level, pitch level, aberrant oropharyngeal resonance, hoarse voice, reduced stress, and prolonged phonemes. These findings suggest that speech disorders in DS are due to distributed impairments involving voice, speech sound production, fluency, resonance, and prosody. These data contribute to the development of a profile of impairments in speakers with DS to guide future research and inform clinical assessment and treatment.

Influence of a Specific Aquatic Program on Social and Gross Motor Skills in Adolescents with Autism Spectrum Disorders: Three Case Reports

Swimming pool activities revealed to be efficacious to train psychomotor skills and increase adaptive behaviors in children with Autism Spectrum Disorders (ASD). Therefore, the purpose of this study was to investigate the efficacy of a specific multi-systemic aquatic therapy (CI-MAT) on gross motor and social skills in three adolescents with Autism Spectrum Disorders (ASD).

METHODS

three adolescents with ASD of which two boys (M1 with a chronological age of 10.3 years and a mental age of 4.7 years; M2 with a chronological age of 14.6 and a mental age inferior to 4 years) and one girl (chronological age of 14.0 and a mental age inferior to 4 years). The study was divided into three phases: baseline, 12-week CI-MAT program and Post-Test. Participants were administered a battery of tests incorporating anthropometric measurements, gross motor development test and a social skills questionnaire before and after a 12-week MAT-CI program.

RESULTS

Subjects improved locomotors and object control skills following the CI-MAT program in a different way. Concerning social behaviors, the higher proportion of gains was observed in the sensitivity of other's presence and eye contact, for the contact domain, and in the comply turn for the relationship domain.

CONCLUSIONS

The results of this study showed that the CI-MAT program was effective for the development of gross-motor skills and social behaviors in subjects with ASD. Moreover there is an urge to carry out a whole psychological assessment targeting both motor and adaptive development suitable to provide educational and vocational plans of exercises for people with ASD.

Motor and cognitive development of children with Down syndrome: The effect of acquisition of walking skills on their cognitive and language abilities

OBJECTIVE

This study investigated the relationship between motor and cognitive/language development in children with Down syndrome (DS). We also tested the hypothesis that acquisition of walking skills facilitates later cognitive/language development.

METHODS

Participants were 156 children with DS who were less than 48 months old and had undergone a health checkup by medical doctors and received rehabilitation treatment between April 2013 and March 2017 in Yokohama, Japan. To assess their development, the Kyoto Scale of Psychological Development (KSPD) 2001 was used, which measures development in three subdomains: Posture-Motor (P-M), Cognitive-Adaptive (C-A), and Language-Social (L-S). To investigate the relationship between motor and cognitive/language development, partial correlation analyses were conducted that controlled for participants' age. To test the effect of achieving walking skills, regression analyses were conducted using only data from participants who took the KSPD at least twice and could not walk at the initial test.

RESULTS

P-M developmental age (DA) was significantly and positively correlated with both C-A DA and L-S DA in children 1-3 years old. The relationship strengthened with increased age. Acquisition of walking skills had a significant positive effect on both the C-A DA and L-S DA at the second test when controlling for the C-A DA and L-S DA at the first test and age at the second test.

CONCLUSION

Motor development was correlated with both cognitive and language development in young children with DS. Results also suggested that achievement of walking could facilitate later cognitive/language development in children with DS.

Gross motor proficiency and intellectual functioning: A comparison among children with Down syndrome, children with borderline intellectual functioning, and typically developing children

This cross-sectional study examines differences in gross motor proficiency as a function of different intellectual functioning profiles. Two motor areas have been investigated as being equally essential to gross motor functions in every-day life: locomotion and object control.It aims to compare gross motor skills endorsed by children with Down syndrome (DS), children with borderline intellectual functioning (BIF), and typically developing children (TDC).Group 1 was composed of 18 children with DS (chronological age = 8.22), group 2 was composed of 18 children with BIF (chronological age = 9.32), and group 3 was composed of 18 children with typical development (TD) (chronological age = 9.28).Gross motor skills were measured through the test of gross motor development (TGMD-Test) composed of locomotion and object control tasks.Children with DS showed worse gross motor skills compared with children with BIF and typically developing children by underscoring both on all locomotion (e.g., walking, running, hopping, galloping, jumping, sliding, and leaping) and all object control tasks (e.g., throwing, catching, striking, bouncing, kicking, pulling, and pushing).In DS group strengths were found on run and slide skills, in BIF group strengths were on run, long jump and slide skills and in TDC group strengths were on run and slide skills. For all of the 3 groups the locomotor worst performed task was jump forward with arm swing.Findings suggest implications for further practice to develop evidence-based exercise programs aimed to rehabilitate gross motor skills through the regular participation in structured exercise activities.

Influência do ambiente domiciliar no desenvolvimento motor de lactentes com síndrome de Down

RESUMO Crianças com síndrome de Down apresentam atrasos no desenvolvimento neuropsicomotor relacionados a tônus muscular, controle postural e equilíbrio. O desenvolvimento motor sofre interferência multifatorial, que envolve características biológicas, psicológicas, sociais e ambientais. Assim, o ambiente em que o lactente está incluído pode atuar como facilitador do desenvolvimento neuropsicomotor. O objetivo deste estudo foi avaliar a influência do ambiente domiciliar no desenvolvimento motor de lactentes com síndrome de Down. Participaram do estudo 16 lactentes com a síndrome, divididos em grupo I (3 a 11 meses) e grupo II (12 a 18 meses), avaliados pela Alberta Infant Motor Scale (AIMS) e pelo questionário Affordances in the Home Environment for Motor Development - Infant Scale (AHEMD-IS). A análise de dados foi feita por meio do teste de Kruskal-Wallis, coeficiente de correlação de Spearman e teste de razão de verossimilhança. Os resultados evidenciaram uma correlação positiva significativa entre o escore bruto da AIMS e a variedade de estímulos (p=0,01, r=0,78) e com o escore total do questionário AHEMD-IS (p=0,02, r=0,74) no grupo II. Verificou-se, ainda, correlação entre a renda familiar e as oportunidades com brinquedos de função motora grossa (p=0,05, r=0,49), porém com correlação fraca. Conclui-se que o ambiente domiciliar tem importante papel no desenvolvimento motor de crianças com síndrome de Down entre 12 e 18 meses, por proporcionar oportunidades de vivências e experimentações. Assim, pode-se afirmar que ambientes mais adequados proporcionam melhor desempenho motor.

Speech-language therapy stimulation in children with Down’s syndrome

ABSTRACT Objective: to analyze the contributions of speech-language therapy to the language development of children with Down syndrome (DS). Methods: eleven children with DS participated in the research. The children were between zero and five years of age, of both genders and attending a university extension project involving eight therapy sessions following stimulation guidelines. Children were evaluated before and after speech-language stimulation. The stimulation guidelines were based on the following aspects of language development: coordination of sensorimotor schema, constitution of object permanence, gestural/body imitation, imitation of utterances, deferred imitation and use of symbolic schema, communicative intent, receptive vocabulary and expressive vocabulary: words and phrases. The study was approved by the Research Ethics Committee of the institution. Data were analyzed quantitatively. Results: there were significant differences in the pre- and post-speech-language intervention in the following skills parameters: gestural/body imitation, imitation of utterances, deferred imitation and use of symbolic schema, communicative intent and receptive vocabulary. Conclusion: early stimulation of linguistic and cognitive aspects is important in the development of children with DS, as evidenced by the immediate development of speech-language skills in children after the intervention.

Using computational support in motor ability analysis of individuals with Down syndrome: Literature review

BACKGROUND

The lack of motor ability is one of the main Down syndrome (DS) effects. However, there are several types of motor disorders that can be attenuated or corrected if they are early identified and properly analyzed.

OBJECTIVES

The aim of our study is to support the local Physical Activity research group, which works with about 25 DS children, by means of computational resources for motor analysis. To that end, we first needed to identify the main computational approaches that support the motor analysis of DS individuals, if they are already connected to intervention programs, and potential opportunities to extend the current state of the art.

METHOD

We carried out a systematic review that identified 28 papers from the current literature. These papers were then analyzed to answer the research questions defined in our study.

RESULTS

Our main findings were: (1) the temporal distribution of papers shows this area is new and it is starting to create a body of knowledge that in fact supports motor treatments of DS individuals; (2) there is a diversity of studies that consider different research directions such as comparisons of motor features of DS with non-DS individuals, characterization of DS motor features, and approaches for intervention programs to improve DS motor abilities; (3) there are several types of sensing hardware that enables the development of studies from different perspectives; (4) spatial monitoring is performed but only in laboratory conditions; (5); mathematical tools are largely used while strategies based on artificial intelligence for automated analysis are ignored; and (6) proposals for DS post-intervention monitoring are not found in the literature.

CONCLUSION

DS motor analysis is still a new research area and it is not mature yet. Thus, the use of computational resources is very pragmatic and focused only on mathematical tools that support the numerical analysis of the acquired data. The main proposals for motor analysis are performed in laboratory, so that there are several opportunities to create computational resources to obtain real-time data on the move. The integration of this data with intervention strategies is also a potential area for future researches.

Developmental trend of children with Down's syndrome - How do sex and neonatal conditions influence their developmental patterns?

OBJECTIVE

This study investigated factors that would influence developmental trend of children with Down's syndrome (DS) in three different domains (motor, cognitive, language), specifically focusing on the effect of sex and neonatal conditions, including preterm birth, low birth weight, and congenital heart disease (CHD).

METHODS

The participants were 158 children with DS (mean age at the initial test = 25.5 months) receiving clinical service at a rehabilitation center in Yokohama, Japan. Kyoto Scale of Psychological Development was used to measure developmental level, which derive total developmental age (DA), Posture-motor DA, Cognitive-adaptive DA, and Language-social DA. For the analyses, a multilevel model for change was adopted, as the model allowed us to investigate intrapersonal growth and the between-personal factors that are associated with individual differences in the pattern of growth.

RESULTS

The developmental speed of children with DS was found to be slower than that of typical children in all the three developmental domains assessed (i.e., the estimated coefficient of the slope for chronological age on DA was less than 1). DS Girls developed significantly faster than boys in non-verbal cognitive and language abilities. Low birth weight and CHD had a significant negative impact on development of non-verbal cognitive abilities for boys, but had a somewhat positive effect for girls.

CONCLUSION

As was shown in previous studies, the result of this study indicated that the children with DS develop slower than non-disabled children. Low birth weight and CHD were found to influence developmental trend of children with DS, differently for boys and girls.

Can early physical therapy positively affect the onset of independent walking in infants with Down syndrome? A retrospective cohort study

BACKGROUND

The development of both gross and fine motor skills in a child with Down syndrome is generally delayed. The most seriously affected stage is the achievement of independent walking ability, which influences the onset of all following motor and cognitive skills. The study objectives were: 1) to assess the time taken to achieve independent walking ability in a cohort of children with Down syndrome; 2) to examine differences in walking onset by patient characteristics; and 3) to verify the effect of early physical therapy (neurodevelopmental treatment based on Bobath Concept practiced within the first months of life) in the achievement of that skill.

METHODS

A retrospective study was carried out on a cohort of 86 children with Down Syndrome. The knowledge of the exact age of walking onset and information about comorbidities and rehabilitation practiced since birth were the eligibility criteria.

RESULTS

The average age at which walking began in the sample was 26 months (standard deviation=9.66). Some patient characteristics proved to be related negatively to the walking onset: gender male, trisomy 21, improved joint ligamentous laxity. When practiced, early physical therapy was able to contrast the delay in walking.

CONCLUSIONS

NDT-Bobath is a well-known and valid instrument for a child with Down syndrome to attain his highest possible psychomotor functioning level. This study pointed out for the first time ever its capability to contrast the delay on walking onset, which can influence positively the development of the following motor and cognitive skills.

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.

The biology, pathogenesis and clinical aspects of acute lymphoblastic leukemia in children with Down syndrome

Children with Down syndrome (DS) are at a 20-fold increased risk for acute lymphoblastic leukemia (DS-ALL). Although the etiology of this higher risk of developing leukemia remains largely unclear, the recent identification of CRLF2 (cytokine receptor like factor 2) and JAK2 mutations and study of the effect of trisomy of Hmgn1 and Dyrk1a (dual-specificity tyrosine phosphorylation-regulated kinase 1A) on B-cell development have shed significant new light on the disease process. Here we focus on the clinical features, biology and genetics of ALL in children with DS. We review the unique characteristics of DS-ALL on both the clinical and molecular levels and discuss the differences in treatments and outcomes in ALL in children with DS compared with those without DS. The identification of new biological insights is expected to pave the way for novel targeted therapies.