Down syndrome-A narrative review with a focus on anatomical features

Down Syndrome in Children: A Primary Immunodeficiency with Immune Dysregulation

Background: The multisystemic features of Down syndrome (DS) in children are accompanied by immunodeficiency, making them susceptible to infections and immune dysregulation with autoimmune, allergic, inflammatory, and hematological complications. This study was aimed at a better understanding of the abnormalities within the B and T cell compartments and their correlations with clinical immunophenotypes. Methods: Medical records of 35 DS children were retrospectively reviewed, referring to clinical symptomatology including history of infections, immune dysregulation disorders, and humoral and cellular immune response. Results: While the etiology of respiratory tract infections included typical viral and bacterial pathogens, SARS-CoV2-induced inflammatory disease and syndromic immunodeficiency contributed significantly to the deterioration of the clinical course. Allergic diseases in the form of asthma, allergic rhinitis, and alimentary allergy were the most frequent manifestations of immune dysregulation and were followed by autoimmune disorders, such as Crohn's disease, celiac disease, autoimmune thyroiditis, and alopecia, as well as inflammatory disorders, balanitis xerotica obliterans and lymphadenopathy, and a hematological disorder of myelopoiesis. Deficiency of serum immunoglobulin levels, reduced numbers of naïve B cells, and non-switched memory B cells along with low naïve T helper cells and significantly reduced regulatory T helper cells were the most prominent immune abnormalities. Conclusions: The loss of naïveté in B and T lymphocyte compartments with a deficiency of regulatory T cells may be underpinning pathomechanisms for the skewed immune response. The clinical immunophenotype in DS is complex and represents syndromic primary immunodeficiency with immune dysregulation.

Awareness of down syndrome screening among educated Muslim women is associated with a favorable attitude toward testing

OBJECTIVE

There is a general assumption that Muslim women refuse Down syndrome screening, and therefore, many health practitioners do not offer it or briefly discuss it with their participants. This study aims to objectively assess women's awareness, knowledge, and attitudes toward Down Syndrome screening (D.S.S) in a Muslim-majority population.

METHODS

We conducted a cross-sectional study among attendees of antenatal clinics at a major university hospital in Saudi Arabia, aiming for a sample size of at least 385 Muslim women. A semi-structured questionnaire assessed awareness of different D.S.S. options and the source of that information (2 items), specific knowledge of D.S.S. (14 items), and attitudes (4 items). The knowledge and attitudes scores were calculated using a five-level agreement Likert-type scale.

RESULTS

Among 434 participants, with an even distribution among all age groups and a majority of a college degree holder or higher (71%), 178 (41.0%) reported awareness of D.S.S. Factors associated with increased awareness were maternal age above 40 or those under 30, nulliparity, and extended family history of fetal congenital anomalies (P-value = 0.03,0.015, and 0.017, respectively). Recognized tests were ultrasound measurement of nuchal translucency (71.9%) and first-trimester serum screening (58.4%). The sources of knowledge were obstetricians (53.9%), followed by family and friends (27.0%). The overall mean ± SD knowledge score was 53.9 ± 8.7 out of 70, and the mean attitude score was 17.4 ± 2.9 out of 20. Having 1 or 2 children is associated with a higher knowledge score, and most participants who reported awareness of D.S.S. (51.7%) had a favorable attitude toward screening.

CONCLUSION

Awareness of D.S.S. among Muslim women is associated with favorable attitudes towards testing, contradicting the general assumption and highlighting the need for systematic education to increase awareness and subsequent testing uptake.

The surge in heart rate and blood pressure at respiratory event termination is dampened in children with down syndrome

BACKGROUND

Children with Down syndrome (DS) have a high prevalence of sleep disordered breathing (SDB) and altered cardiovascular autonomic control. We aimed to analyze the effect of DS on the surge in heart rate (HR) and pulse transit time (PTT, an inverse surrogate measure of blood pressure change) at respiratory event termination.

METHODS

44 children (3-19 y) with DS and 44 typically developing (TD) children matched for SDB severity, age and sex underwent overnight polysomnography. Multilevel modelling determined the effect of DS on HR and PTT changes between a 10s pre-event to the latter half of each respiratory event (late-event) and 15s post-event during NREM and REM, accounting for SDB severity and event length.

RESULTS

The children with DS had a significantly smaller % change in HR late-event to post-event (NREM: DS 26.4 % ± 17.5 % (mean ± SD), TD 30.7 % ± 21.0 %; REM DS 16.9 % ± 15.3 %, TD 21.0 % ± 14.0 %; p < 0.05 for both) compared with TD children for obstructive events, and central events (13.2 % ± 17.0 %, TD 18.8 % ± 17.0 %; p < 0.01) during REM. %change in PTT was significantly smaller in the DS group during NREM and REM from pre-event and late-event to post-event compared with TD children for obstructive and central events.

CONCLUSION

These results suggest children with DS have dampened HR and BP responses to respiratory events compared with TD children. Whether this is symptomatic of autonomic dysfunction or a protective factor for the cardiovascular system in children with DS remains to be elucidated.

Dysregulation of the Immune System in a Natural History Study of 1299 Individuals with Down Syndrome

Dysregulation of the immune system in individuals with Down syndrome is thought to play a major role in the pathophysiology of many clinical presentations. This natural history of disease study took a comprehensive evaluation of the prevalence of different immune related diagnoses in a cohort of 1299 patients with Down syndrome compared to a 2605 patient control cohort at the Mount Sinai Health System in New York, NY over the past 18 years. We conducted a stepwise analysis of the odds of receiving a diagnosis at the Chapter, Sub-chapter and Diagnosis level of the ICD-CM-10 code system. Individuals in our Down syndrome cohort had higher odds of a diagnosis with inflammatory and autoimmune presentations such as Alopecia areata (OR 6.06, p = 0.01), Other sepsis (OR 4.79, p < 0.001, Purpura and other hemorrhagic conditions (OR 2.31, p < 0.001), and Rosacea (OR 3.11, p < 0.001). They also presented with lower odds of a diagnosis of Herpesviral infection (OR 0.42, p = 0.01), and Viral warts (OR 0.51, p = 0.04). We posit that dysregulation of the immune system in individuals with Down syndrome has impact on infectious diseases, including lowering the incidence of viral disease and increasing its severity. Our data also suggests inflammation and autoimmune mediated diseases, in particular of the skin, are exacerbated in individuals with Down syndrome. Finally, there may be a need for greater clinical attention to non-emergent conditions within the Down syndrome patient population as those can also greatly affect quality of life.

Dysregulation of the Immune System in a Natural History Study of 1299 Individuals with Down Syndrome

Dysregulation of the immune system in individuals with Down syndrome is thought to play a major role in the pathophysiology of many clinical presentations. This natural history of disease study took a comprehensive evaluation of the prevalence of different immune related diagnoses in a cohort of 1299 patients with Down syndrome compared to a 2605 control cohort of patients without Down syndrome at Mount Sinai Health System in NY, NY over the past 18 years. We conducted a stepwise analysis of the odds of receiving a diagnosis at the Chapter, Sub-chapter and Diagnosis level of the ICD-CM-10 code system. Individuals in our Down syndrome cohort had higher odds of a diagnosis with inflammatory and autoimmune presentations such as Alopecia areata (OR 6.06, p = 0.01), Other sepsis (OR 4.79, p < 0.001, Purpura and Other hemorrhagic conditions (OR 2.31, p < 0.001), and Rosacea (OR 3.11, p < 0.001). They also presented with lower odds of a diagnosis of Herpesviral infection (OR 0.42, p = 0.01), and Viral warts (OR 0.51, p = 0.04). We posit that dysregulation of the immune system in individuals with Down syndrome has impact on infectious diseases, including lowering the incidence of viral disease, and increasing its severity. Our data also suggests inflammation and autoimmune mediated diseases, in particular of the skin, is exacerbated in individuals with Down syndrome. Finally, there may be a need for greater clinical attention to non-emergent conditions within the Down syndrome patient population as those can also greatly affect quality of life.

Sleep disordered breathing improvement prevents worsening of autonomic dysfunction in children with Down syndrome

BACKGROUND

Resolution of sleep disordered breathing (SDB) in typically developing children normalises heart rate variability (HRV), a measure of autonomic control, to that of non-snoring controls. Children with Down Syndrome (DS) have dampened heart rate variability (HRV) but the effect of treatment is not known. To assess the effect of improvement of SDB on autonomic control we compared HRV in children with DS whose SDB improved over 2 y, to those whose SDB did not improve.

METHODS

24 children (3-19 y) had a baseline and follow-up polysomnographic study 2 y later. Improved SDB was defined as a reduction in obstructive apnea hypopnea index (OAHI) to ≤ 50% of baseline. Children were grouped into Improved (n = 12) and Unimproved (n = 12). Power spectral analysis of the ECG determined low frequency (LF), high frequency (HF) power and the LF/HF ratio. Seven children in the Improved and 2 in the Unimproved group were treated following the baseline study.

RESULTS

In the Unimproved group at follow-up, LF power was lower compared to baseline during N3 and Total Sleep (p < 0.05 for both). HF power was lower during REM (p < 0.05). HRV remained unchanged between studies in the Improved group.

CONCLUSION

Autonomic control worsened as indicated by lower LF and HF power in children whose SDB was not improved. In contrast, in those children with improved SDB, autonomic control remained the same, suggesting improvement in SDB severity prevents further worsening of autonomic control in children with DS.

A Multimodal Imaging-Supported Down Syndrome Mouse Model of RSV Infection

Individuals with Down syndrome (DS) are more prone to develop severe respiratory tract infections. Although a RSV infection has a high clinical impact and severe outcome in individuals with DS, no vaccine nor effective therapeutics are available. Any research into infection pathophysiology or prophylactic and therapeutic antiviral strategies in the specific context of DS would greatly benefit this patient population, but currently such relevant animal models are lacking. This study aimed to develop and characterize the first mouse model of RSV infection in a DS-specific context. Ts65Dn mice and wild type littermates were inoculated with a bioluminescence imaging-enabled recombinant human RSV to longitudinally track viral replication in host cells throughout infection progression. This resulted in an active infection in the upper airways and lungs with similar viral load in Ts65Dn mice and euploid mice. Flow cytometric analysis of leukocytes in lungs and spleen demonstrated immune alterations with lower CD8+ T cells and B-cells in Ts65Dn mice. Overall, our study presents a novel DS-specific mouse model of hRSV infection and shows that potential in using the Ts65Dn preclinical model to study immune-specific responses of RSV in the context of DS and supports the need for models representing the pathological development.

Classifications of Odontoid Process Fractures: A Systematic Review and Proposal of a New Simplified Classification System Based on Embryology

Odontoid fractures are the most common cervical spine fractures in the elderly. Although many classification systems have been developed for them, the ambiguity in various definitions can potentially lead to misunderstandings. This paper aims to review the terminologies and current classification systems of odontoid fractures and propose a new, simplified anatomical classification. Given the descriptive variability of odontoid fractures in current classifications, we systematically reviewed the literature using PRISMA guidelines querying the National Library of Medicine PubMed database. The initial literature search yielded 175 publications. A total of seven reports met the inclusion criteria and were ultimately included for a full review. The classification systems previously used to categorize fractures of the odontoid process often need to be more transparent, imprecise, and incongruous. To simplify them, a new embryologically accurate system is proposed. A new embryological and anatomically-based system, combining the former systems' specific attributes, allows a more straightforward and adaptable classification of odontoid fractures.

Consequences of chromosome gain: A new view on trisomy syndromes

Chromosome gains are detrimental for the development of the human embryo. As such, autosomal trisomies almost always result in spontaneous abortion, and the rare embryos surviving until live birth suffer from a plethora of pathological defects. There is no treatment currently available to ameliorate the consequences of trisomies, such as Down syndrome (trisomy of chromosome 21). Identifying the source of the phenotypes observed in cells with extra chromosomes is crucial for understanding the underlying molecular causes of trisomy syndromes. Although increased expression of the genes localized on the extra chromosome triggers several pathological phenotypes, an alternative model suggests that global, aneuploidy-associated changes in cellular physiology also contribute to the pathology. Here, we compare the molecular consequences of trisomy syndromes in vivo against engineered cell lines carrying various chromosome gains in vitro. We point out several phenotypes that are shared by variable trisomies and, therefore, might be caused by the presence of an extra chromosome per se, independent of its identity. This alternative view may provide useful insights for understanding Down syndrome pathology and open additional opportunities for diagnostics and treatments.

Effects of 24-week basketball programme on body composition and functional fitness on adults with Down syndrome

BACKGROUND

The body index [body mass, body mass index (BMI), waist circumference and waist-height ratio] and functional fitness (aerobic capacity, muscular strength, balance, flexibility and functional ability) of people with Down syndrome (DS) are substantially lower than those in the general population, as DS has an overall negative impact on health.

AIMS

This study explored the effect of a 24-week basketball training programme on the body composition and functional fitness of adults with DS.

METHODS AND PROCEDURE OUTCOMES

Twenty-two adults with DS (24 ± 6 years; 25 ± 4 kg/m² ) were randomly allocated to the experimental (n = 11, 67.04 kg) and control groups (n = 11, 69.36 kg). The experimental group performed 24 weeks of basketball programme training (3 times per week, 60 min per session), while the control group maintained their daily activities without any special physical training. Body composition and functional fitness parameters were measured before and after the intervention. To evaluate the differences between groups, an analysis of covariance (ANCOVA) was used while controlling for differences at baseline.

RESULTS

Hip circumference and waist-height ratio were statistically different at baseline between the intervention and control groups. After the 24-week basketball training programme, the results showed significant differences between the exercise and control groups for hip circumference, body mass, BMI, waist circumference, hip circumference, waist-height ratio, flexibility, aerobic capacity, static and dynamic balance, balance and basketball functional ability (P < 0.05). The exercise group showed significant improvements in all variables of body composition and functional fitness (P < 0.05) except for the waist-hip ratio. There was no statistical significance between all physical composition and functional health variables in the control group except for the standing long jump (P > 0.05), with effect sizes ranging from small to large.

CONCLUSIONS AND IMPLICATIONS

The basketball training programme improved body composition and functional fitness of adults with DS.

Musladin-Lueke Syndrome in a Dog: Case Report

The aim of this study is to report the case of a 4-month-old Beagle dog diagnosed with Musladin-Lueke syndrome. The dog appeared to walk on the digits ("tiptoes") with all limbs during ambulation and rigid extension of the carpus, elbow, tarsus, and knee joints during ambulation. Thickening of the fur and auricular cartilage, reduction in radiocarpal, and tibiotarsal joint amplitude, macrocephaly, and lateralized eyes were noticed on physical examination. Echocardiography showed reduced mobility and altered (tortuous) valve morphology. Bilateral abdominal cryptorchidism was confirmed by ultrasonography. Musladin-Lueke syndrome was the presumptive diagnosis, based on the clinical signs presented. The diagnosis was confirmed after DNA testing performed by serial collection of saliva. This is the first paper that describes unprecedented cardiac and reproductive changes of Musladin-Lueke syndrome in which the dog was followed for 2 years, presenting a good quality of life.

Tiny Toes to Tau Tangles: Down's Syndrome and Its Association With Alzheimer's Disease

Down’s syndrome (DS) is a common genetic condition caused by the trisomy of chromosome 21, which leads to the development of many multisystemic complications, early-onset Alzheimer’s disease (AD) being one of its most common complications. In this article, we have performed an intensive literature review that established a strong relationship between AD and DS. These two conditions are clubbed pathologically, clinically, and diagnostically to understand the association between AD and DS. This article focuses on understanding the impact of AD on a DS patient on both clinical and pathological levels and exploring some advanced treatment modalities. It has also emphasized the importance of early screening and diagnosis for AD in this group of patients to prevent AD development. Regular monitoring, early diagnosis, and a proper treatment plan can slow the AD occurrence in DS patients.

Implications of Down's syndrome on oral health status in patients: A prevalence-based study

BACKGROUND

Down syndrome which is also known as "trisomy 21" is the commonest chromosomal defect that has been associated with intellectual disability or impairment. Clinically, it has been characterized by the generalized presence of hypotonic musculature, variety of neurobiological alterations, numerous respiratory diseases, and significantly higher risk of developing infection along with various dental abnormalities and oro-facial dysmorphological changes. Periodontal diseases are the most prominent oral health issue among individuals diagnosed with Down Syndrome.

AIM

The objective of the present prevalence analysis was to study the implications of Down's syndrome on oral health status among patients.

MATERIALS AND METHODS

This was a descriptive and cross-sectional prevalence analysis conducted within a duration of 1 year. A total of 100 children diagnosed with Down syndrome (aged between 5 and 16 years) were selected as the study sample. Inclusion criteria were (a) cytogenetic positive trisomy 21, (b) cooperative behavior, and (c) written informed consent obtained from the legal care-takers. Exclusion criteria were (a) any debilitating form of systemic diseases, (b) any other disability, and (c) extremely uncooperative children. The gingival health status was assessed using gingival index (GI) [Loe and Silness], calculus index (CI) [Ramfjord], and plaque index (PI) [Silness and Loe]. Information involving the practice of oral hygiene maintenance, diet plans, and parental educational status was derived from each parent. Based upon their intelligence quotient (I. Q.) values, the subjects were classified into three groups: a) mild (I. Q. level = 50 to 70), b) moderate (I. Q. level = 35 to 50), and c) severe (I. Q. level ≤35). Statistical analysis was performed using the statistical software tool Statistical Package for Social Sciences (SPSS) version 20.0. Qualitative data were recorded as frequencies, and percentages and quantitative data were recorded as mean and standard deviation values. All categorical outcomes were analyzed by means of the Chi-square test. The quantitative outcomes of Calculus Index, Gingival Index, and Plaque Index were analyzed by either student's t-test or one-way analysis of variance (ANOVA). Significance was set at a cut-off value of P < 0.05.

RESULTS

Down syndromic children between 12 and 16 years were reported to have statistically significant higher Calculus Index, Gingival Index, and Plaque Index values in comparison with younger age syndromic children (P < 0.01). Those with severe mental retardation had significantly higher Plaque Index (P < 0.001) and Gingival Index (P < 0.04) values when compared with those with mild and moderate mental retardation. No significant difference in comparing Calculus Index was noted.

CONCLUSION

Higher age group children with Down syndrome require close monitoring by parents for assisting in maintaining oral hygiene practices just as in younger age group children.

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.

Application of intelligent algorithms in Down syndrome screening during second trimester pregnancy

BACKGROUND

Down syndrome (DS) is one of the most common chromosomal aneuploidy diseases. Prenatal screening and diagnostic tests can aid the early diagnosis, appropriate management of these fetuses, and give parents an informed choice about whether or not to terminate a pregnancy. In recent years, investigations have been conducted to achieve a high detection rate (DR) and reduce the false positive rate (FPR). Hospitals have accumulated large numbers of screened cases. However, artificial intelligence methods are rarely used in the risk assessment of prenatal screening for DS.

AIM

To use a support vector machine algorithm, classification and regression tree algorithm, and AdaBoost algorithm in machine learning for modeling and analysis of prenatal DS screening.

METHODS

The dataset was from the Center for Prenatal Diagnosis at the First Hospital of Jilin University. We designed and developed intelligent algorithms based on the synthetic minority over-sampling technique (SMOTE)-Tomek and adaptive synthetic sampling over-sampling techniques to preprocess the dataset of prenatal screening information. The machine learning model was then established. Finally, the feasibility of artificial intelligence algorithms in DS screening evaluation is discussed.

RESULTS

The database contained 31 DS diagnosed cases, accounting for 0.03% of all patients. The dataset showed a large difference between the numbers of DS affected and non-affected cases. A combination of over-sampling and under-sampling techniques can greatly increase the performance of the algorithm at processing non-balanced datasets. As the number of iterations increases, the combination of the classification and regression tree algorithm and the SMOTE-Tomek over-sampling technique can obtain a high DR while keeping the FPR to a minimum.

CONCLUSION

The support vector machine algorithm and the classification and regression tree algorithm achieved good results on the DS screening dataset. When the T21 risk cutoff value was set to 270, machine learning methods had a higher DR and a lower FPR than statistical methods.

The Test-Retest Reliability of the Bruininks-Oseretsky Test of Motor Proficiency-Short Form in Youth with Down Syndrome-A Pilot Study

Background: It is unclear whether assessments of motor proficiency are reliable for individuals with Down syndrome. The purpose of the study was to evaluate the test–retest reliability of the Bruininks–Oseretsky Test of Motor Proficiency-Short Form (BOT-2 SF) in youth with Down syndrome. Methods: Ten youth (ages 13.1–20.7 years) with Down syndrome completed the BOT-2 SF (14 items) plus a standing long jump on two separate occasions. Intraclass correlation coefficients (ICC), 95% confidence intervals (CIs), and standard error of measurement (SEM) were calculated to determine the test–retest reliability of the BOT-2 SF and the standing long jump. Results: The test–retest reliability of the BOT-2 SF overall scores and percentile rankings were considered excellent. The test–retest reliability of each of the subtests varied with classifications of poor (n = 5), fair to good (n = 6), and excellent (n = 4). Conclusion: Current evidence suggests that children with Down syndrome have reduced motor skills. However, there appears to be a lack of assessment tools that reliably evaluate the motor skills of this population. The results from this investigation suggest that the BOT-2-SF provides “excellent reliability” (≥0.75) to assess the motor skills in youth with Down syndrome.

Peroxisomes of the Brain: Distribution, Functions, and Associated Diseases

Peroxisomes are versatile cell organelles that exhibit a repertoire of organism and cell-type dependent functions. The presence of oxidases and antioxidant enzymes is a characteristic feature of these organelles. The role of peroxisomes in various cell types in human health and disease is under investigation. Defects in the biogenesis of the organelle and its function lead to severe debilitating disorders. In this manuscript, we discuss the distribution and functions of peroxisomes in the nervous system and especially in the brain cells. The important peroxisomal functions in these cells and their role in the pathology of associated disorders such as neurodegeneration are highlighted in recent studies. Although the cause of the pathogenesis of these disorders is still not clearly understood, emerging evidence supports a crucial role of peroxisomes. In this review, we discuss research highlighting the role of peroxisomes in brain development and its function. We also provide an overview of the major findings in recent years that highlight the role of peroxisome dysfunction in various associated diseases.

Vestibular function in adults with intellectual disabilities: feasibility and outcome of a vestibular screening protocol in Special Olympics athletes

OBJECTIVE

This study aimed to evaluate the feasibility of a well-adapted vestibular screening battery to objectively examine the (peripheral) vestibular function, and to explore the characteristics of potential vestibular deficits in the adult ID population.

DESIGN

Cross-sectional study design.

STUDY SAMPLE

Compared to an age- and gender-weighted control group, a heterogeneous group of forty-five adults with ID participated in the vestibular screening at the National Games of Special Olympics Belgium (2019), which consisted of a bone conduction cervical Vestibular Evoked Myogenic Potential (cVEMP) measurement and video Head Impulse Test (vHIT).

RESULTS

The screening battery appeared to be feasible in the majority of the participants (cVEMP: 92%; vHIT: 72%). Overall, the occurrence of abnormal cVEMP and vHIT responses was significantly higher in the ID group, with significantly lower corrected peak-to-peak cVEMP amplitudes (p < 0.001), lower vHIT gains (p < 0.001), and higher cVEMP and vHIT asymmetry ratios in the ID group (p = 0.008 and p < 0.001 resp.).

CONCLUSIONS

Vestibular assessment using the cVEMP and vHIT technique shows a promising feasibility in adults with ID. In addition, this study suggests that people with ID exhibit an increased prevalence of (peripheral) vestibular deficits relative to the general population.

The effect of 8 weeks of freestyle swim training on the functional fitness of adults with Down syndrome

BACKGROUND

Studies conducted on adults with Down syndrome have demonstrated the improvement of functional fitness (aerobic capacity, muscular strength, balance, flexibility, functional ability, body mass or body mass index) with varying exercise modalities but often with one or two components in isolation. Such modalities included walking, running, cycling, rowing or resistance training. Freestyle swim training has shown significant improvements of all parameters associated with functional fitness in the general population. Swimming is an aerobic activity where many of the large muscle groups are involved and may provide more functional fitness benefits. As a consequence, the purpose of our study was to investigate the effect of freestyle swim training on the functional fitness of adults with Down syndrome.

METHODS

Twenty-six adults with Down syndrome (33 ± 6 years; 34 ± 9 kg/m² ) were randomly allocated to an exercise (n = 13; 81.3 kg) or control group (n = 13; 81.5 kg). The exercise group performed 8 weeks of freestyle swim training, three times a week, 30 min per session (increased to 40 min after 4 weeks). To evaluate differences between groups, a one-way analysis of variance was used, controlling for differences at baseline.

RESULTS

After 8 weeks of training, the results showed significant differences between the exercise and control group for body mass, body mass index, aerobic capacity, dynamic balance, muscular strength, 12-m swim time and functional ability (P < 0.05). Effect sizes ranged from small to large.

CONCLUSIONS

Various components of functional fitness improved significantly after an intervention period of freestyle swim training. The collective improvement of many functional fitness parameters shown by this study may hold benefits for these often-neglected and in many cases functionally impaired individuals.

Detección de un mosaico de trisomía 21 en líquido amniótico

Se analizó un resultado con alteración cromosómica tomado de una base de datos conformada por un total de 4755 muestras de líquido amniótico extraídos mediante amniocentesis con indicación de su médico tratante, riesgo sérico y edad materna avanzada. En este reporte se presenta la detección de un mosaico de trisomía 21 en líquido amniótico, mediante la técnica de Banda G donde se analizaron 20 metafases. Los resultados obtenidos documentan una composición cromosómica 47, XY+21 y 46, XY con una relación 9:11 respecto a las metafases analizadas, confirmándose así el diagnostico del Síndrome de Down secundario a mosaico.

CNS organoids: an innovative tool for neurological disease modeling and drug neurotoxicity screening

The paradigm of central nervous system (CNS) drug discovery has mostly relied on traditional approaches of rodent models or cell-based in vitro models. Owing to the issues of species differences between humans and rodents, it is difficult to correlate the robustness of data for neurodevelopmental studies. With advances in the stem-cell field, 3D CNS organoids have been developed and explored owing to their resemblance to the human brain architecture and functions. Further, CNS organoids provide a unique opportunity to mimic the human brain physiology and serve as a modeling tool to study the normal versus pathological brain or the elucidation of mechanisms of neurological disorders. Here, we discuss the recent application of a CNS organoid explored for neurodevelopment disease or a screening tool for CNS drug development.

Pharmacotherapy of Down’s Syndrome: When and Which?

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Down Syndrome (DS) is an essential genetic disease that involves many other body systems along with cerebral functions. The postnatal approach to treat this genetic disease includes intervention on various related disorders (e.g., heart failure, respiratory, oral, ear, and hearing disorders). However, different proposed treatments do not significantly improve the quality of life of these subjects. Another approach to the treatment of DS considering the possibility to intervene on the embryo was recently introduced. As of this, the current study has reviewed different outcomes regarding DS treatment in an animal model, namely the Ts65Dn mouse. The obtained results encouraged spending more time, efforts, and resources in this field. Besides, various treatment strategies were tried to include genetic modification, treatment with vasoactive intestinal peptide derivatives or fluoxetine. However, the main obstacle to the use of these possible treatments is the ethical issues it raises. The progression of the pregnancy in spite of awareness that DS affects the unborn and prenatal treatment of DS injured embryo are relevant dilemmas. Thus, talented researchers should spend more efforts to improve the quality of life for people affected by DS, which will allow probably a better approach to the ethical issues.

Genotypic diversity and acidogenicity of Streptococcus mutans in Down syndrome children

AIMS

To evaluate the genotypic diversity and acidogenicity of Streptococcus mutans (S. mutans) and the potential association of these factors with dental caries experience in children with DS compared to non-DS children (controls).

METHODS AND RESULTS

Seventeen children (age 6-12 years) with high salivary S. mutans counts (> 2.5 × 10⁵ CFU/mL) were selected and divided into two groups: DS and non-DS. Five children in each group were caries-free, while the remainder had elevated caries experience. S. mutans isolates were obtained from each participant. The genotypic profile of the isolates was analyzed with the AP-PCR methodology. The acidogenicity of a representative strain from each genotype of S. mutans was also evaluated. DS children had 16 different S. mutans genotypes, while the control group had 21. Twelve genotypes were present in both groups and one of them was associated with caries-free status (P < .05). Although the acidogenicity of the genotypes found in DS children was significantly lower (P < .05) compared to controls, this fact was not associated with caries experience in both groups.

CONCLUSIONS

DS children have a lower S. mutans genotypic diversity and genotypes with lower acidogenicity than those of non-DS children. However these findings were not associated with their caries experience.

Physical therapy in Down syndrome: systematic review and meta-analysis

BACKGROUND

Down syndrome is the most common chromosomal abnormality, with a worldwide incidence of around 0.1% in live births. It is related to several conditions in which the physical therapy could take action-preventing co-morbidities. This study aims to evaluate the effectiveness of physical therapy in Down syndrome, to know and compare the effectiveness of different physical therapy interventions in this population.

METHODS

A systematic review and a meta-analysis of randomised controlled trials were conducted. The search was performed during June 2018 in the following databases: PubMed, Web of Science, Physiotherapy Evidence Database and Scopus. The studies were selected using predefined inclusion and exclusion criteria. The Physiotherapy Evidence Database scale evaluated the quality of the methods used in the studies. Subsequently, the data were extracted, and statistical analysis was performed when possible.

RESULTS

A total of 27 articles were included, of which nine contributed information to the meta-analysis. Statistical analysis showed favourable results for the strength of upper and lower limbs [standardised mean difference (SMD) = 1.46; 95% confidence interval (CI): (0.77-2.15); and SMD = 2.04; 95% CI: (1.07-3.01)] and mediolateral oscillations of balance [SMD = -3.30; 95% CI: (-5.34 to -1.26)].

CONCLUSIONS

The results show the potential benefit of certain types of physical therapy interventions, specifically in strength and balance, in people with Down syndrome. There are still many aspects to clarify and new lines of research.

Downregulation of Endothelin Receptor B Contributes to Defective B Cell Lymphopoiesis in Trisomy 21 Pluripotent Stem Cells

Individuals with Trisomy 21 (T21) exhibit numerous hematological abnormalities, including reductions in numbers of circulating B and T lymphocytes. To elucidate molecular mechanisms underlying these phenotypes, we differentiated human isogenic disomic and trisomic pluripotent cells, and observed that trisomic cells showed defects in B cell, but not T cell differentiation. Global gene expression of differentiated, trisomic B cells revealed reduced expression of genes encoding endothelin signaling components, namely the Endothelin Receptor B (EDNRB), and its ligand Endothelin1 (EDN1). Depletion of EDNRB mRNA in cord blood-derived CD34⁺ cells led to defective B cell differentiation, supporting a hypothesis that low EDNRB expression in T21 contributes to intrinsic lymphoid defects. Further evidence for the role of the EDNRB pathway in B cell differentiation was obtained through CRISPR/Cas9 gene targeting in disomic and trisomic iPS cells. Knockout of EDNRB in both cell backgrounds reduced the capacity for B cell differentiation. Collectively, this work identifies downregulation of EDNRB as a causative factor for impaired B lymphocyte generation in trisomic cells, which may contribute to defects in immune function associated with T21. Furthermore, a novel role for endothelin signaling in regulation of B cell development has been identified.

Augmentative and alternative communication in children with Down's syndrome: a systematic review

BACKGROUND

The use of technology to assist in the communication, socialization, language, and motor skills of children with Down's syndrome (DS) is required. The aim of this study was to analyse research findings regarding the different instruments of 'augmentative and alternative communication' used in children with Down's syndrome.

METHODS

This is a systematic review of published articles available on PubMed, Web of Science, PsycInfo, and BVS using the following descriptors: assistive technology AND syndrome, assistive technology AND down syndrome, down syndrome AND augmentative and alternative communication. Studies published in English were selected if they met the following inclusion criteria: (1) study of children with a diagnosis of DS, and (2) assistive technology and/or augmentative and alternative communication analysis in this population.

RESULTS

A total of 1087 articles were identified. Thirteen articles met the inclusion criteria. The instruments most used by the studies were speech-generating devices (SGDs) and the Picture Exchange Communication System (PECS).

CONCLUSION

Twelve instruments that provided significant aid to the process of communication and socialization of children with DS were identified. These instruments increase the interaction between individuals among this population and their peers, contributing to their quality of life and self-esteem.

Does the Visual Channel Improve the Perception of Consonants Produced by Speakers of French With Down Syndrome?

PURPOSE

This work evaluates whether seeing the speaker's face could improve the speech intelligibility of adults with Down syndrome (DS). This is not straightforward because DS induces a number of anatomical and motor anomalies affecting the orofacial zone.

METHOD

A speech-in-noise perception test was used to evaluate the intelligibility of 16 consonants (Cs) produced in a vowel-consonant-vowel context (Vo = /a/) by 4 speakers with DS and 4 control speakers. Forty-eight naïve participants were asked to identify the stimuli in 3 modalities: auditory (A), visual (V), and auditory-visual (AV). The probability of correct responses was analyzed, as well as AV gain, confusions, and transmitted information as a function of modality and phonetic features.

RESULTS

The probability of correct response follows the trend AV > A > V, with smaller values for the DS than the control speakers in A and AV but not in V. This trend depended on the C: the V information particularly improved the transmission of place of articulation and to a lesser extent of manner, whereas voicing remained specifically altered in DS.

CONCLUSIONS

The results suggest that the V information is intact in the speech of people with DS and improves the perception of some phonetic features in Cs in a similar way as for control speakers. This result has implications for further studies, rehabilitation protocols, and specific training of caregivers.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.6002267.

Fetopathological examination for the fetuses with Down syndrome in Tunisia: Epidemiological study and associated malformations

BACKGROUND

For Down syndrome (DS), traditional epidemiological studies to determine the prevalence, cause, and clinical significance of the syndrome have been conducted over the last 100 years. In Tunisia, the current work is the first in-depth study in epidemiology of DS from fetopathological data.

AIM OF THE STUDY

The aim of this epidemiological study was to determine the impact of some feto-maternal characteristics in occurrence of DS and to search the frequency of associated congenital malformations with this syndrome.

METHODS

Our retrospective study was realized for 144 fetuses with DS among 9321 autopsied fetuses in embryo-fetopathological service between 1994 and 2011.

RESULTS

In our study, the majority of mothers (72.91%) were 35 years and older, with a statistically significant difference (p<10^-6, OR=16.7, CI=8.7-32.4). The abnormalities of extremities (31%) were the most common fetal abnormalities followed by facial (23.51%) and digestive abnormalities (19.63%).

CONCLUSION

One of the main conclusions of this research is that the most common risk factor for DS is maternal age. On the other hand, the type and the frequency of associated congenital anomalies with DS are still controversial.

Deleterious Effects of Chronic Folate Deficiency in the Ts65Dn Mouse Model of Down Syndrome

Folate is an important B vitamin naturally found in the human diet and plays a critical role in methylation of nucleic acids. Indeed, abnormalities in this major epigenetic mechanism play a pivotal role in the pathogenesis of cognitive deficit and intellectual disability in humans. The most common cause of cognitive dysfunction in children is Down syndrome (DS). Since folate deficiency is very common among the pediatric population, we questioned whether chronic folate deficiency (CFD) exacerbates cognitive dysfunction in a mouse model of DS. To test this, adult Ts65Dn mice and their disomic littermates were chronically fed a diet free of folic acid while preventing endogenous production of folate in the digestive tract for a period of 8 weeks. Our results show that the Ts65Dn mouse model of DS was significantly more vulnerable to CFD in terms of plasma homocysteine and N5-methyltetrahydrofolate (5-MTHF) levels. Importantly, these changes were linked to degenerative alterations in hippocampal dendritic morphology and impaired nest building behavior in Ts65Dn mice. Based on our results, a rigorous examination of folate intake and its metabolism in individuals with DS is warranted.

Meiotic Divisions: No Place for Gender Equality

In multicellular organisms the fusion of two gametes with a haploid set of chromosomes leads to the formation of the zygote, the first cell of the embryo. Accurate execution of the meiotic cell division to generate a female and a male gamete is required for the generation of healthy offspring harboring the correct number of chromosomes. Unfortunately, meiosis is error prone. This has severe consequences for fertility and under certain circumstances, health of the offspring. In humans, female meiosis is extremely error prone. In this chapter we will compare male and female meiosis in humans to illustrate why and at which frequency errors occur, and describe how this affects pregnancy outcome and health of the individual. We will first introduce key notions of cell division in meiosis and how they differ from mitosis, followed by a detailed description of the events that are prone to errors during the meiotic divisions.