Down syndrome: Prevalence and distribution of congenital heart disease in Brazil

Isolated pulmonary valve endocarditis in a pediatric patient with down syndrome

BACKGROUND

Isolated pulmonary valve endocarditis (IPE) accounts for less than 2% of all infective endocarditis patients. It is commonly associated with several predisposing factors, including intravenous drug use (IVDU) and congenital heart disease. The most common causative pathogens of IPE are Staphylococcus aureus and Streptococcus viridans. We report a Down's syndrome patient with IPE and with no standard risk factors caused by the rare pathogen Acinetobacter spp. This led to respiratory failure and systemic infection due to septic pulmonary emboli. Early elective surgery was decided upon as the patient was no longer responding to medical therapy, and his clinical condition was worsening over time.

CASE PRESENTATION

A 15-year-old male with Down syndrome and no underlying heart defect presented with a 3-month history of episodic fever, nausea, vomiting, and diarrhea. Transthoracic echocardiography (TTE) revealed large vegetation on the pulmonary valve leaflet, another mobile mass at the pulmonary artery bifurcation, and severe pulmonary regurgitation. Serial blood cultures isolated Acinetobacter spp. Despite initial antibiotic therapy, the patient continued to have sepsis, unresolved vegetations, and developed life-threatening complications and respiratory distress, which convinced us to perform a pulmonary valve replacement surgery with a homograft. After surgery, the patient recovered and was discharged on the ninth postoperative day (POD).

CONCLUSION

This report highlights IPE's diagnostic and therapeutic challenges, alongside the importance of a comprehensive cardiopulmonary workup in patients with unexplained fever, sepsis, and pulmonary symptoms, even without typical risk factors. Based on the patient's aggravating condition despite medical treatment, early surgical intervention and pulmonary valve replacement were deemed crucial. However, there still needs to be a definitive guideline on when and how surgery should be performed in patients with complicated IPE, especially in pediatric patients.

Nationwide hospitalizations of patients with down syndrome and congenital heart disease over a 15-year period

Down syndrome is one of the most common genetic diseases, generally associated with an increased probability of congenital heart diseases. This increased risk contributes to escalated levels of morbidity and mortality. In this study, we sought to analyze nationwide data of pediatric and adult patients with Down syndrome and congenital heart disease over a 15-year period. Data obtained from the hospital discharge form between 2001 and 2016 of patients diagnosed with Down syndrome in Italy and at least one congenital heart disease were included. Information on 12362 admissions of 6527 patients were included. Age at first admission was 6.2 ± 12.8 years and was a predictor of mortality (HR = 1.51, 95% CI 1.13-2.03, p = 0.006). 3923 (60.1%) patients underwent only one admission, while 2604 (39.9%) underwent multiple (> 1) admissions. There were 5846 (47.3%) admissions for cardiac related symptoms. Multiple admissions (SHR: 3.13; 95% CI: 2.99, 3.27; P < 0.01) and cardiac admissions (SHR: 2.00; 95% CI: 1.92, 2.09; P < 0.01) were associated with an increased risk of additional potential readmissions. There was an increased risk of mortality for patients who had cardiac admissions (HR = 1.45, 95% CI: 1.08-1.94, p = 0.012), and for those who underwent at least 1 cardiac surgical procedure (HR = 1.51, 95% CI 1.13-2.03, p = 0.006).

CONCLUSIONS

A younger age at first admission is a predictor for mortality in patients with Down syndrome and congenital heart disease. If patients undergo more than one admission, the risk of further readmissions increases. There is a pivotal role for heart disease in influencing the hospitalization rate and subsequent mortality.

WHAT IS KNOWN

• Down syndrome individuals often face an increased risk of congenital heart diseases. • Congenital heart diseases contribute significantly to morbidity and mortality in Down syndrome patients.

WHAT IS NEW

• This study analyzes nationwide data covering a 15-year period of pediatric and adult patients in Italy with Down syndrome and congenital heart disease. • It identifies a younger age at first admission as a predictor for mortality in these patients, emphasizing the criticality of early intervention. • Demonstrates a correlation between multiple admissions, particularly those related to cardiac issues, and an increased risk of further readmissions, providing insights into the ongoing healthcare needs of these individuals.

Analysis of Down syndrome newborn outcomes in three neonatal intensive care units in Rio de Janeiro, Brazil

OBJECTIVE

The aim of this study was to analyze the outcomes of newborns with Down syndrome admitted to three neonatal intensive care units in the city of Rio de Janeiro, Brazil.

METHODS

A retrospective cohort study was conducted by analyzing the medical records between 2014 and 2018 of newborns with Down syndrome admitted to three neonatal intensive care units. The following variables were analyzed: maternal and perinatal data, neonatal malformations, neonatal intensive care unit intercurrences, and outcomes.

RESULTS

A total of 119 newborns with Down syndrome were recruited, and 112 were selected for analysis. The most common maternal age group was >35 years (72.07%), the most common type of delivery was cesarean section (83.93%), and the majority of cases were male (53.57%). The most common reasons for neonatal intensive care unit hospitalization were congenital heart disease (57.66%) and prematurity (23.21%). The most common form of feeding was a combination of human milk and formula (83.93%). The second most common malformation was duodenal atresia (9.82%). The most common complications during neonatal intensive care unit hospitalization were transient tachypnea of the newborn (63.39%), hypoglycemia (18.75%), pulmonary hypertension (7.14%), and sepsis (7.14%). The mean length of stay in the neonatal intensive care unit was 27 days. The most common outcome was discharge (82.14%). Furthermore, 12.50% of newborns were transferred to an external neonatal intensive care unit, and 6% died.

CONCLUSION

Newborns with Down syndrome are more likely to be admitted to the neonatal intensive care unit, and the length of hospital stay is longer due to complications related to congenital malformations common to this syndrome and prematurity.

Investigation of cardiopulmonary parameters, motor development and muscle strength in children with Down syndrome with and without congenital heart disease

BACKGROUND

Children with Down syndrome (DS) frequently have concomitant clinical problems. There are no studies in the literature evaluating gross motor development and handgrip strength in the presence of congenital heart disease (CHD), which is one of the most common comorbidities in population with DS. The aim of this study was to compare cardiopulmonary parameters, gross motor development and handgrip strength in children with DS with and without CHD.

METHODS

A total of 28 children with DS (14 with CHD and 14 without CHD) were evaluated. Demographic data and cardiopulmonary parameters were recorded. Gross motor development and handgrip strength were assessed.

RESULTS

Children with DS and CHD had lower GMFM-88 scores and right handgrip strength and higher Wang respiratory score than children with DS and no CHD (P < 0.05). GMFM-88 scores were moderately correlated with resting oxygen saturation (r = 0.46, P = 0.01) and right handgrip strength (r = 0.67, P < 0.001).

CONCLUSIONS

Peripheral muscle strength and oxygen saturation may be factors affecting gross motor development in children with DS. From this point of view, evaluating cardiopulmonary parameters, motor development and handgrip strength in children with DS and CHD is important to identify risks, provide early intervention and support development.

Human Genetics of Congenital Heart Defects

Congenital heart diseases (or congenital heart defects/disorders; CHDs) are structural abnormalities of the heart and/or great vessels that are present at birth. CHDs include an extensive range of defects that may be minor and require no intervention or may be life-limiting and require complex surgery shortly after birth. This chapter reviews the current knowledge on the genetic causes of CHD.

Unraveling Down Syndrome: From Genetic Anomaly to Artificial Intelligence-Enhanced Diagnosis

Down syndrome arises from chromosomal non-disjunction during gametogenesis, resulting in an additional chromosome. This anomaly presents with intellectual impairment, growth limitations, and distinct facial features. Positive correlation exists between maternal age, particularly in advanced cases, and the global annual incidence is over 200,000 cases. Early interventions, including first and second-trimester screenings, have improved DS diagnosis and care. The manifestations of Down syndrome result from complex interactions between genetic factors linked to various health concerns. To explore recent advancements in Down syndrome research, we focus on the integration of artificial intelligence (AI) and machine learning (ML) technologies for improved diagnosis and management. Recent developments leverage AI and ML algorithms to detect subtle Down syndrome indicators across various data sources, including biological markers, facial traits, and medical images. These technologies offer potential enhancements in accuracy, particularly in cases complicated by cognitive impairments. Integration of AI and ML in Down syndrome diagnosis signifies a significant advancement in medical science. These tools hold promise for early detection, personalized treatment, and a deeper comprehension of the complex interplay between genetics and environmental factors. This review provides a comprehensive overview of neurodevelopmental and cognitive profiles, comorbidities, diagnosis, and management within the Down syndrome context. The utilization of AI and ML represents a transformative step toward enhancing early identification and tailored interventions for individuals with Down syndrome, ultimately improving their quality of life.

Congenital Heart Defects and Outcome in a Large Cohort of Down Syndrome: A Single-Center Experience from Turkey

OBJECTIVE

Congenital heart defects occur in approximately 50% of children with Down syndrome and they contribute considerably to morbidity and mortality. The aim of this study is to investigate the prevalence, classification, and survival of congenital heart defects in Down syndrome.

MATERIALS AND METHODS

About 1731 Down syndrome patients who underwent echocardiography between 1986 and 2022 were evaluated. The median follow-up duration was 8.7 years (range 1-35.8 years). Congenital heart defect was grouped as cyanotic and acyanotic.

RESULTS

Among the 1731 patients, 52.1% had congenital heart defects. Congenital heart defect was significantly more common in females than males. The most common cardiac defect was ventricular septal defect (35%), followed by atrial septal defect (31.8%), atrioventricular septal defect (23.4%), tetralogy of Fallot (5%), and patent ductus arteriosus (3.6%). In the follow-up, 43.2% of atrial septal defect, 17.8% of ventricular septal defect, and a total of 20% of congenital heart defects were closed spontaneously. About 34.4% of congenital heart defect was corrected by cardiac surgery/intervention. Five-year survival rate was 97.4% in patients without congenital heart defects, whereas it was 95.6% in mild congenital heart defects and 86.1% in moderate to severe congenital heart defects. There was no relationship between consanguinity, parental age, maternal disease, folic acid supplementation before/during pregnancy, gestational age, birth weight, and congenital heart defects. Neuromotor development was similar in patients with and without congenital heart defects.

CONCLUSION

We demonstrated that almost half of the patients had congenital heart defects; ventricular septal defect was the most common congenital heart defect type. This study is valuable in terms of the largest single-center study describing the classification, prognostic factors, and survival of Down syndrome patients with congenital heart defect from Turkey.

Cardiovascular Complications of Down Syndrome: Scoping Review and Expert Consensus

Cardiovascular disease is a leading cause of morbidity and mortality in individuals with Down syndrome. Congenital heart disease is the most common cardiovascular condition in this group, present in up to 50% of people with Down syndrome and contributing to poor outcomes. Additional factors contributing to cardiovascular outcomes include pulmonary hypertension; coexistent pulmonary, endocrine, and metabolic diseases; and risk factors for atherosclerotic disease. Moreover, disparities in the cardiovascular care of people with Down syndrome compared with the general population, which vary across different geographies and health care systems, further contribute to cardiovascular mortality; this issue is often overlooked by the wider medical community. This review focuses on the diagnosis, prevalence, and management of cardiovascular disease encountered in people with Down syndrome and summarizes available evidence in 10 key areas relating to Down syndrome and cardiac disease, from prenatal diagnosis to disparities in care in areas of differing resource availability. All specialists and nonspecialist clinicians providing care for people with Down syndrome should be aware of best clinical practice in all aspects of care of this distinct population.

Risk for Severe Illness and Death among Pediatric Patients with Down Syndrome Hospitalized for COVID-19, Brazil

Down syndrome is the most common human chromosomal disorder. Whether Down syndrome is a risk factor for severe COVID-19 outcomes in pediatric patients remains unclear, especially in low-to-middle income countries. We gathered data on patients <18 years of age with SARS-CoV-2 infection from a national registry in Brazil to assess the risk for severe outcomes among patients with Down syndrome. We included data from 14,684 hospitalized patients, 261 of whom had Down syndrome. After adjustments for sociodemographic and medical factors, patients with Down syndrome had 1.8 times higher odds of dying from COVID-19 (odds ratio 1.82, 95% CI 1.22-2.68) and 27% longer recovery times (hazard ratio 0.73, 95% CI 0.61-0.86) than patients without Down syndrome. We found Down syndrome was associated with increased risk for severe illness and death among COVID-19 patients. Guidelines for managing COVID-19 among pediatric patients with Down syndrome could improve outcomes for this population.

The evolving treatment of congenital heart disease in patient with Down syndrome: Current state of knowledge

OBJECTIVES

Children with Down syndrome are usually seen as not worthy of high-risk cardiac surgery. Through this review, we try to show the results of curative and palliative surgery for functional single ventricle syndrome in patients with Down syndrome, as there is currently no standard protocol for the treatment of this category of patients.

METHODS

An exhaustive search of all related published medical literature included the following domains: Down syndrome and diagnosis, Down syndrome and taxonomy, Down syndrome, and natural history, Down syndrome and cardiovascular abnormalities, Down syndrome and pulmonary hypertension, Down syndrome and institutionalization, Down syndrome and surgical repair, Down syndrome, and single ventricle palliation, Down syndrome and Glenn, Down syndrome, and Fontan.

RESULTS

12 articles were included from 775 identified. Low-risk cardiac surgery procedure should be provided for Down syndrome with a balanced ventricular septal defect. There is no universal agreement about the surgical approach for Down syndrome with unbalanced ventricular septal defects, but it can be performed at relatively low risk.

CONCLUSIONS

TCPC in Down syndrome patients could be a relatively low-risk procedure if patients are prepared well and their pulmonary vascular resistance is low. Randomized prospective studies are required to show the long-term impact of TCPC palliation and develop a better understanding of standardized care of these patients.

Maternal Risk Factors Triggering Congenital Heart Defects in Down Syndrome: A Case-Control Study

OBJECTIVES

Maternal MTHFR and MTRR polymorphisms as a risk of CHD in DS fetus were studied along with maternal folic acid supplementation, which could influence the folate metabolism along with other risk factors.

MATERIAL AND METHODS

A case-control study comprising of mothers of DS with and without CHD along with controls were recruited from a tertiary care center since 2018-2019. Genomic DNA was isolated followed by PCR-RFLP.

RESULTS

Mothers with age ≥35 years and having history of miscarriages have a higher risk of giving birth to DS with CHD (n = 35% and 42%, respectively). Mothers who carried the MTHFR 677CT/TT and MTRR 524CT/TT genotypes combination in the folic acid nonusers group during pregnancies had six-fold (OR = 6.909, p-value = 0.027; 95% CI-1.23 ± 38.51) and four-fold (OR = 4.75, p-value = 0.040; 95% CI-1.067 ± 21.44) increased odds of having a DS child with CHD, respectively, as compared to folic acid users.

CONCLUSION

Maternal age, folic acid supplementation, and previous history of miscarriages is involved in the etiology of CHD in DS fetus in Indian population. Maternal MTHFR and MTRR polymorphisms are also involved in the occurrence of CHD and DS in Indian population when controlling for periconceptional folic acid supplementation.

LIMITATIONS

Single-Centered Study.

Prevalence of pulmonary hypertension among children with Down syndrome: A systematic review and meta-analysis

BACKGROUND

Pulmonary hypertension (PH) has serious short- and long-term consequences. PH is gaining increasing importance in high risk groups such as Down syndrome (DS) as it influences their overall survival and prognosis. Hence, there is a dire need to collate the prevalence rates of PH in order to undertake definitive measures for early diagnosis and management.

AIM

To determine the prevalence of PH in children with DS.

METHODS

The authors individually conducted a search of electronic databases manually (Cochrane library, PubMed, EMBASE, Scopus, Web of Science). Data extraction and quality control were independently performed by two reviewers and a third reviewer resolved any conflicts of opinion. The words used in the literature search were “pulmonary hypertension” and “pulmonary arterial hypertension”; “Down syndrome” and “trisomy 21” and “prevalence”. The data were analyzed by Comprehensive Meta-Analysis Software Version 2. Risk of bias assessment and STROBE checklist were used for quality assessment.

RESULTS

Of 1578 articles identified, 17 were selected for final analysis. The pooled prevalence of PH in these studies was 25.5%. Subgroup analysis was carried out for age, gender, region, year of publication, risk of bias and etiology of PH.

CONCLUSION

This review highlights the increasing prevalence of PH in children with DS. It is crucial for pediatricians to be aware of this morbid disease and channel their efforts towards earlier diagnosis and successful management. Community-based studies with a larger sample size of children with DS should be carried out to better characterize the epidemiology and underlying etiology of PH in DS.

[Congenital heart disease associated with the most prevalent chromosomal syndromes: a literature review]

Most frequent chromosomal syndromes like Down, Patau, Edwards, Turner, and Williams affect the pediatric population in various ways, and congenital heart disease explains the altered quality of life they suffer. There is a lack of studies reviewing the cardiac anomalies in these syndromes, and the ones that exist are publications from past decades. We reviewed databases such as MEDLINE, LILACS, SCIELO, and Google Scholar, selecting the best possible evidence, and each chromosomal syndrome was investigated in relation to congenital heart disease, constituting five search groups. The article shows the characteristics of each heart disease described in the studies reviewed, the author, date of publication, country, and population studied, as well as a brief description of the frequency of the disease and its mortality. The results described in this review were contrasted with previous existing literature to verify if there was correspondence between the reported frequencies. The most frequent congenital heart diseases were atrioventricular septal defect (AVSD), ventricular septal defect (VSD), atrial septal defect (ASD), and persistent ductus arteriosus (PDA) in Down syndrome patients, PDA, ASD, and VSD in Patau syndrome patients, AVSD, PDA and valvular defects in Edwards syndrome, bicuspid aortic valve, aortic coarctation and aortic stenosis in Turner syndrome, and supravalvular aortic stenosis and pulmonary stenosis in Williams syndrome.

Congenital heart disease in Down syndrome – A review of temporal changes

Background

Congenital heart disease (CHD) is a well-known co-occurring condition in Down syndrome (DS). We aimed to review the literature to evaluate the current evidence to address key questions.

Methods

A series of key questions were formulated a priori to inform the search strategy and review process. These addressed the topics of prevalence, type of CHD, severity, and screening. Using the National Library of Medicine database, PubMed, detailed literature searches were performed. The quality of available evidence was then evaluated, the existing literature was summarized, and knowledge gaps were identified.

Results

Fifty-six relevant original articles were identified which addressed at least one key question. Study details, including: research design, internal validity, external validity, and relevant results are presented. The total prevalence of CHD reported in DS ranged from 20 to 57.9%. In later decades, the prevalence remained constant at 40—55%. The types and classification of CHD varied considerably between studies. Some studies indicate a trend towards a milder phenotype, but this was not consistent. Over time, some studies observed an improved prognosis for CHD in DS. Studies investigating screening for CHD by physical examination, chest X-ray, and electrocardiogram report sensitivities of 71–95%.

Conclusion

To further improve knowledge on CHD in DS, we suggest that future studies cover a wide range of nations and regions, with a longitudinal design, and account for potential confounding factors.

Memorization of daily routines by children with Down syndrome assisted by a playful virtual environment

A child with Down syndrome, like any other child, may benefit from interacting with memory stimuli, but needs additional support and help. The use of special teaching methods, which add playfulness and use of the computer, can enhance the memory processes of these children. In this work, we present the virtual environment "Nossa Vida (Our Life)", which was developed to assist children with Down syndrome to memorize action sequences of their daily routine. A daily routine memorization test (DRMT), consisting of a weekly reminder of typical daily routines completed by the children and parents, was performed before (pre-test) and after (post-test) the intervention. The work involved a multidisciplinary team and assessed the effectiveness of the test performed by 30 children with Down syndrome from APAE, a special education school for children with intellectual disabilities in São Paulo, Brazil. The children were separated into two groups (Experimental - GE and Control - GC) with homogeneity and normality of the data. Two hypotheses were tested in this study: H0 and H1, where: H0 = There is no statistical difference between memorizing daily tasks between individuals with Down syndrome who used our ludic virtual environment and those who used the conventional memory method.H1 = There is a difference between the group of subjects with Down Syndrome who used our virtual game environment and the group that did not use it in relation to memorizing the daily task. This produces t = -14.98 and p <0.0001, with H1 being accepted. The results showed that the EG presented significance in relation to the CG and the evolution mean of the children in the EG was 81.82% higher. According to experts (psychologist and pedagogue) from APAE and parents, the playful activities implemented in this virtual environment have been of great interest to children, who had fun, tested hypotheses and questioned them about the sequences of actions performed in their routine daily.

Maternal risk factors for congenital heart defects in infants with Down syndrome from Western Mexico

Atrioventricular septal defects (AVSDs) have been identified as intriguingly infrequent among Hispanics with Down syndrome (DS) born in the United States. The aim of this study was to evaluate the effect of possible maternal risk factors in the presence of congenital heart defects (CHDs) in Mexican infants with DS. A total of 231 live birth infants born with DS during 2009-2018 at the "Dr. Juan I. Menchaca" Civil Hospital of Guadalajara (Guadalajara, Mexico) were ascertained in a case-control study. Patients with DS with any major CHD were included as cases and those without major CHD as controls. Potential risk factors were analyzed using logistic regression. Of eligible infants with DS, 100 (43.3%) had ≥1 major CHDs (cases) and were compared with a control group of 131 infants (56.7%) with DS without CHDs. Prevalent CHDs were ostium secundum atrial septal defects (ASDs) (46.9%), ventricular septal defects (27.3%), and AVSDs (14%). Lack of folic acid supplementation before pregnancy had a significant risk for CHDs in infants with DS (adjusted odds ratio [aORs] = 2.9 (95% confidence interval [95% CI]: 1.0-8.6) and in the analysis by subtype of CHDs, also, for the occurrence of ASDs (aOR = 11.5, 95% CI: 1.4-94.4). Almost half of the infants with DS in our sample had CHDs, being ASD the commonest subtype and AVSD the rarest. Our ethnic background alone or in concomitance with observed nutritional disadvantages seems to contribute differences in CHD subtype rates in our DS patients.

Evaluation of the masticatory muscle function, physiological sleep variables, and salivary parameters after electromechanical therapeutic approaches in adult patients with Down syndrome: a randomized controlled clinical trial

Background

There are many comorbidities associated with Down syndrome (DS), including obstructive sleep apnea (OSA) and masticatory muscle alteration. Muscular hypotonia, in particular, of the masticatory and oropharyngeal muscles is one of the main characteristics of individuals with DS, resulting in impairments of speech, swallowing, and mastication in these individuals. In addition, total or partial obstruction of the airways during sleep can occur due to pharyngeal hypotonia, leading to snoring and to OSA. This progressive respiratory disorder is associated with a high risk of morbidity and mortality in individuals with DS. The aim of this research is to assess the therapeutic effects of surface neuromuscular electrical stimulation (NMES), the mastication apparatus (MA), and a mandibular advancement oral appliance (OA_m) with an embedded thermosensitive microchip on the functions of masticatory muscles (bilateral masseter and temporal muscles), physiological sleep variables, and salivary parameters in adult patients with DS.

Methods

The patients with DS will be randomly selected and divided into three groups (DS-NMES, DS-MA, and DS-OA_m) with a minimum of 10 patients in each group. A thermosensitive microchip will be embedded in the OA_m to record its compliance. The therapeutic effects on masticatory muscle function will be investigated through electromyography, a caliper, and a force-transducer device; the sleep variables, in turn, will be evaluated by means of polysomnography. The physicochemical and microbiological properties of the saliva will also be analyzed, including the salivary flow, viscosity, buffer capacity, cortisol levels (susceptibility to psychological and/or physical stress), and Pseudomonas aeruginosa levels (risk of aspiration pneumonia) in these patients. The methods determined for this study will be carried out prior to and after 2 months of the recommended therapies.

Discussion

The primary outcomes would be the improvement and/or reestablishment of the function of masticatory muscles and the physiological sleep variables in this target public since individuals with DS commonly present generalized muscular hypotonia and dysfunction of the oropharyngeal musculature. As a secondary outcome indicator, the impact of the applied therapies (NMES, MA, and OA_m) on the salivary microbiological and physicochemical properties in DS individuals will also be assessed. Furthermore, the compliance of OA_m usage will be measured through a thermosensitive microchip.

Trial registration

Registro Brasileiro de Ensaios Clínicos, RBR-3qp5np. Registered on 20 February 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3300-0) contains supplementary material, which is available to authorized users.

The most relevant chromosomal abnormalities in the north of Rio Grande do Sul, Brazil: 26 years of cytogenetic analysis

From 1992 to 2018, cytogenetic analyses were successfully performed to explore the chromosomal abnormalities of 729 patients, who utilised a pioneering counselling service in the city of Passo Fundo in the northern part of the Brazilian state of Rio Grande do Sul. This city is characterised by a large conglomerate of private and public hospitals. A classical cytogenetic analysis and G-banding were performed using the patient samples. Although normal karyotypes were observed for 562 of the cases, 167 individuals evidenced chromosomal alterations. Among those, 110 exhibited numerical alterations (65.86%), 41 demonstrated structural modifications (24.55%) and 16 showed both numerical and structural chromosomal changes (9.58%). This study describes the diversity of the chromosomal alterations in this region, which have not been previously examined. After 26 years of study, the findings are discussed herein in a self-critical form.

Identifying Patients with Atrioventricular Septal Defect in Down Syndrome Populations by Using Self-Normalizing Neural Networks and Feature Selection

Atrioventricular septal defect (AVSD) is a clinically significant subtype of congenital heart disease (CHD) that severely influences the health of babies during birth and is associated with Down syndrome (DS). Thus, exploring the differences in functional genes in DS samples with and without AVSD is a critical way to investigate the complex association between AVSD and DS. In this study, we present a computational method to distinguish DS patients with AVSD from those without AVSD using the newly proposed self-normalizing neural network (SNN). First, each patient was encoded by using the copy number of probes on chromosome 21. The encoded features were ranked by the reliable Monte Carlo feature selection (MCFS) method to obtain a ranked feature list. Based on this feature list, we used a two-stage incremental feature selection to construct two series of feature subsets and applied SNNs to build classifiers to identify optimal features. Results show that 2737 optimal features were obtained, and the corresponding optimal SNN classifier constructed on optimal features yielded a Matthew’s correlation coefficient (MCC) value of 0.748. For comparison, random forest was also used to build classifiers and uncover optimal features. This method received an optimal MCC value of 0.582 when top 132 features were utilized. Finally, we analyzed some key features derived from the optimal features in SNNs found in literature support to further reveal their essential roles.

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.

Gender differences in the prevalence of congenital heart disease in Down's syndrome: a brief meta-analysis

BACKGROUND

Down's syndrome (DS) affects one per 700 live births and congenital heart disease (CHD) occurs in 40-60% of these patients. Contributing factors to the association between DS and CHD are being unraveled. Gender could be one of them.

METHODS

We performed a meta-analysis of CHD prevalence in DS, separated by gender. Three search engines were used and 578 articles were reviewed. Twelve articles were included.

RESULTS

Quantitative analysis showed a higher prevalence of CHD, particularly atrioventricular septal defects (AVSD), in female patients. No differences were found in others forms of CHD.

CONCLUSION

CHD, particularly AVSD, are more common in the female gender of Down's syndrome patients.

Effects of the copy number of ribosomal genes (genes for rRNA) on viability of subjects with chromosomal abnormalities

The number of active ribosomal genes (AcRG) was evaluated in 172 carriers of chromosomal abnormalities (CA) such as Down's syndrome (DS), Robertsonian translocations (RT), Klinefelter's and Turner's syndromes, trisomy Х, disomy Y, and various structural CA. In controls (n=318), AcRG dosage varied from 119 to 190 copies with a mean of 151 copies per diploid genome. In CA carriers, except for DS newborns, AcRG dosage was not beyond these limits. As shown previously, only within these limits cellular homeostasis and organism's viability can be supported, while genomes beyond these limits are eliminated by embryonic loss. About 10% of embryos with DS and 50% of embryos with RT die/are aborted exclusively due to a surplus (DS) or a shortage (RT) of AcRG. AcRG dosage also affects the CA carrier's viability after birth, as demonstrated by comparing newborn and aged (10-40 y.o.) DS patients. Sampling range of AcRG dosage becomes considerably narrower with age: DS newborns ranged from 139 to 194 RG copies (σ²=3.59), while aged DS patients varied from 152 to 190 copies (σ²=1.55) with the same mean. Each CA group showed peculiarities in AcRG dosage distribution. We found that carriers of numerical abnormalities of gonosomes (sex chromosomes) concentrate within the area of medium, most adaptive dosages, whilst carriers of structural CA can only survive with relatively high AcRG number. Our article is the first ever to report an association of CA viability with the genomic number of AcRG.