Prevalence Of Down Syndrome Research Articles

Health and education needs of primary school children with Down Syndrome in England: What can we learn from linked administrative data?

ObjectiveChildren with Down syndrome (DS) have high rates of chronic health conditions (CHCs) which can affect special education needs and primary school placement (mainstream or special). We assessed timing and type of CHC by year-specific primary school placement (ages 5 to 11 years). ApproachWe followed two cohorts: first, a birth cohort of all children with DS born from 2003 to 2020 in England using hospital administrative data; second, a sub-cohort with linked hospital and education records who enrolled in state-funded primary schools in England at age 5 from 2009/10 to 2013/14. We calculated the cumulative incidence of CHCs and multimorbidity (defined as distinct CHCs affecting two or more body systems) from birth through age 11, accounting for variable follow-up and the competing risk of death. We assessed multimorbidity by school placement over time. ResultsThe birth cohort included 11,478 children with DS (prevalence: 0.11%). By age 5, 6.2% of children had died, 80.8% had at least one recorded CHC, and 53.4% had multiple CHCs. Corresponding figures by age 11 were 6.9%, 87.4% and 65.9%, respectively. 85% of children with DS alive at school entry linked to a school record. 72% were enrolled in mainstream primary school at age 5, decreasing to 62% by age 7, and 54% by age 11. ConclusionsMost children with DS have multiple hospital-recorded CHCs. Nearly three-quarters start mainstream primary school, but just over half remain by age 11. ImplicationsParents, clinicians, and educators will benefit from understanding relationships between multimorbidity and school placement.

Down syndrome and associated atrioventricular septal defects in a nationwide Norwegian cohort: Prevalence, time trends, and outcomes.

The prevalence of Down syndrome (DS) is approximately 1 per 1000 births and is influenced by increasing maternal age over the last few decades. DS is strongly associated with congenital heart defects (CHDs), especially atrioventricular septal defect (AVSD). Our objectives were to investigate the prevalence of live-born infants with DS having a severe CHD in the Norwegian population over the last 20 years and compare outcomes in infants with AVSD with and without DS. Information on all births from January 1, 2000 to December 31, 2019 was obtained from the Medical Birth Registry of Norway. We also obtained data on all infants with severe CHDs in Norway registered in Oslo University Hospital's Clinical Registry for Congenital Heart Defects during 2000-2019 and accessed individual-level patient data from the electronic hospital records of selected cases. Infants with AVSD and DS were compared to infants with AVSD without chromosomal defects. Crude and adjusted odds ratios (ORs) of infant mortality and need for surgery during the first year of life, with associated 95% confidence intervals (CIs), were estimated by logistic regression. A total of 1 177 926 infants were live-born in Norway during the study period. Among these, 1456 (0.1%) had DS. The prevalence of infants with DS having a severe CHDs was relatively stable, with a mean of 17 cases per year. The most common CHD associated with DS was AVSD (44.4%). Infants with AVSD and DS were more likely to have cardiac intervention during their first year of life compared to infants with AVSD without chromosomal defects (adjusted OR [aOR]: 2.52; 95% CI 1.27, 4.98). However, we observed no difference in infant mortality during first year of life between the two groups (aOR: 1.08; 95% CI 0.43, 2.70). The prevalence of live-born infants with severe CHDs and DS has been stable in Norway across 20 years. Infants with AVSD and DS did not have higher risk of mortality during their first year of life compared to infants with AVSD without chromosomal defects, despite a higher risk of operative intervention.

Absent or hypoplastic nasal bone: What to tell the prospective parents?

Absent or hypoplastic nasal bone (AHNB) on first or second-trimester ultrasonography (USG) is an important soft marker of Down syndrome. However, due to its varied incidence in euploid and aneuploid fetuses, there is always a dilemma of whether to go for invasive fetal testing for isolated AHNB. This study aims to assess outcomes specifically within the context of Indian ethnicity women. This was a prospective observational study. All patients who reported with AHNB in the first- or second-trimester USG were included. Genetic counseling was done, and noninvasive and invasive testing was offered. Chromosomal anomalies were meticulously recorded, and pregnancy was monitored. The incidence of AHNB in our study was 1.16% (47/4051). Out of 47 women with AHNB, the isolated condition was seen in 32 (0.78%) cases, while AHNB with structural anomalies was seen in nine cases (0.22%). Thirty-nine women opted for invasive testing. Six out of 47 had aneuploidy (12.7%), while two euploid cases (4.25%) developed nonimmune hydrops. The prevalence of Down syndrome in fetuses with AHNB was 8.5% (4/47) and 0.42% (17/4004) in fetuses with nasal bone present. This difference was statistically significant (p = .001). The results indicate that isolated AHNB cases should be followed by a comprehensive anomaly scan rather than immediately recommending invasive testing. However, invasive testing is required when AHNB is associated with other soft markers or abnormalities. As chromosomal microarray is more sensitive than standard karyotype in detecting chromosomal aberrations, it should be chosen over karyotype.

Empowering Lives: Navigating the Landscape of Down Syndrome Support in Saudi Arabia

This study offers an in-depth analysis of Down syndrome (DS) in Saudi Arabia, encompassing healthcare, societal integration, and policy frameworks. It assesses DS prevalence within the Saudi population against global rates and underscores the progress in prenatal diagnostics and screening for early detection. The significance of neonatal care and early intervention programs in the comprehensive development of children with DS is highlighted. The paper explores societal perceptions and efforts to increase public awareness and reduce stigma, with a particular focus on media and educational initiatives. It reviews the educational landscape for individuals with DS, touching on inclusive policies and specialized programs, and evaluates the effectiveness and obstacles of these approaches. The study also compares Saudi policies and legal protections for individuals with DS to international standards, illustrating the country’s advancements toward global norms. It examines support systems, including contributions from nonprofits, community programs, and family services, and concludes with an identification of ongoing challenges and recommendations for future enhancements. This comprehensive overview underlines the importance of a multifaceted approach to supporting individuals with DS in Saudi Arabia, aiming to enhance their quality of life and ensure their full integration into society.

Down-Syndrome-Related Maternal Dysbiosis Might Be Triggered by Certain Classes of Antibiotics: A New Insight into the Possible Pathomechanisms

Down syndrome (DS) is a leading human genomic abnormality resulting from the trisomy of chromosome 21. The genomic base of the aneuploidy behind this disease is complex, and this complexity poses formidable challenges to understanding the underlying molecular basis. In the spectrum of the classic DS risk factor associations, the role of nutrients, vitamins, and, in general, the foodborne-associated background, as part of the events ultimately leading to chromosome nondisjunction, has long been recognized as a well-established clinical association. The integrity of the microbiome is a basic condition in these events, and the dysbiosis may be associated with secondary health outcomes. The possible association of DS development with maternal gut microbiota should therefore require more attention. We have hypothesized that different classes of antibiotics might promote or inhibit the proliferation of different microbial taxa; and hence, we might find associations between the use of the different classes of antibiotics and the prevalence of DS through the modification of the microbiome. As antibiotics are considered major disruptors of the microbiome, it could be hypothesized that the consumption/exposure of certain classes of antibiotics might be associated with the prevalence of DS in European countries (N = 30). By utilizing three different statistical methods, comparisons have been made between the average yearly antibiotic consumption (1997–2020) and the estimated prevalence of people living with DS for the year 2019 as a percentage of the population in European countries. We have found strong statistical correlations between the consumption of tetracycline (J01A) and the narrow-spectrum, beta-lactamase-resistant penicillin (J01CF) and the prevalence of DS.

352 Prevalence and Charactersitics of Moyamoya Syndrome in Patients With Down Syndrome

INTRODUCTION: Moyamoya arteriopathy can be idiopathic (moyamoya disease, MMD) or associated with other diseases, i.e., Down syndrome (moyamoya syndrome, MMS). The prevalence of Down syndrome in patients admitted for moyamoya has been estimated using the National Inpatient Sample to be 3.8%. However, the prevalence of moyamoya in Down Syndrome is not well-quantified. METHODS: This retrospective study used the Sie Center for Down Syndrome and Stroke Program databases at Children’s Hospital Colorado to identify moyamoya patients aged 30 days to 18 years at diagnosis. Demographics, clinical presentation, treatment, and outcome were compared among patients with DS, those with idiopathic MMD, and the entire group. RESULTS: Sixty-five patients (30 idiopathic, 14 MMS with DS, 21 MMS without DS). Prevalence of MMS in the DS population was 0.4%. Gender and age at presentation did not differ significantly between populations. 47% of idiopathic moyamoya patients initially presented with transient ischemic attacks (TIAs) versus 14% of DS patients (P < 0.05). This is compared to 34% of the total population that presented with TIAs. DS patients were more likely to present with stroke (57%) compared to idiopathic (37%) and total patient populations (40%) although these results were not significant. 23% of idiopathic patients presented with basal ganglia strokes compared to 7% in the DS population (P < 0.05). CONCLUSIONS: In this study, the prevalence of moyamoya in DS was 0.4%. Patients with DS were less likely to present with TIAs and more likely to present with stroke, with different stroke locations, than were other moyamoya populations.

Down syndrome screening and diagnosis practices in Europe, United States, Australia, and New Zealand from 1990-2021.

Antenatal screening and diagnostic testing for Down syndrome has greatly advanced over the past 30 years. The goal of this manuscript is to provide a review of the availability and accessibility of prenatal services and selective termination policies across Europe, Australia, New Zealand, and the United States for the period 1990-2021. We collected data from academic peer-reviewed journals, governmental documents, not-for-profit organizations, correspondence with experts, and other online sources without language restrictions. Prenatal screening services from 1990-2021 became increasingly available across countries, enabling expectant couples the opportunity to gain more accurate information earlier in the pregnancy before assuming the risk associated with more invasive techniques like CVS or amniocentesis. Many countries also began adopting prenatal screening as a qualification for prenatal diagnosis. As of 2021, at least 76.9% of countries offered full coverage for diagnostic testing for Down syndrome from government funding. Abortion coverage for a Down syndrome diagnosis was covered fully by government funding in 52.4% of countries in 1990, increasing to 73.8% in 2021. Understanding the changing landscape of prenatal services builds the foundation for future investigation into social policies that affect the prevalence of Down syndrome.

Non-invasive prenatal testing for everybody or contingent screening?

To compare the advantages and disadvantages of two main implementation strategies for non-invasive prenatal testing (NIPT) for the detection of trisomies 21, 13 and 18 in public healthcare settings. These concern NIPT as a first-tier screening test for all pregnant women, or NIPT contingent on an increased risk first-trimester combined test (FCT) result. Comparison based on (un)published data and literature. Despite the lower prevalence of trisomies in the low-risk population, data show that the positive predictive value (PPV) and detection-miscarriage ratio of first-tier NIPT are comparable to NIPT used as contingency test. Advantages of NIPT as a first-tier test compared to FCT with contingent NIPT are that there is no time-window for testing, sensitivity is higher, fewer women need follow-up testing (PPV of NIPT is higher than PPV of FCT), less anxiety for pregnant women and partners. When given the choice, pregnant women prefer first-tier NIPT. Although contingency testing still seems to be the cheaper option, the differences in costs are becoming increasingly smaller and might soon disappear. We argue that NIPT should preferably be offered as a first-tier test for the detection of fetal aneuploidies for all pregnant women, provided that women are supported to make informed decisions. This article is protected by copyright. All rights reserved.

Embryonic organizer formation disorder leads to multiorgan dysplasia in Down syndrome

Despite the high prevalence of Down syndrome (DS) and early identification of the cause (trisomy 21), its molecular pathogenesis has been poorly understood and specific treatments have consequently been practically unavailable. A number of medical conditions throughout the body associated with DS have prompted us to investigate its molecular etiology from the viewpoint of the embryonic organizer, which can steer the development of surrounding cells into specific organs and tissues. We established a DS zebrafish model by overexpressing the human DYRK1A gene, a highly haploinsufficient gene located at the “critical region” within 21q22. We found that both embryonic organizer and body axis were significantly impaired during early embryogenesis, producing abnormalities of the nervous, heart, visceral, and blood systems, similar to those observed with DS. Quantitative phosphoproteome analysis and related assays demonstrated that the DYRK1A-overexpressed zebrafish embryos had anomalous phosphorylation of β-catenin and Hsp90ab1, resulting in Wnt signaling enhancement and TGF-β inhibition. We found an uncovered ectopic molecular mechanism present in amniocytes from fetuses diagnosed with DS and isolated hematopoietic stem cells (HSCs) of DS patients. Importantly, the abnormal proliferation of DS HSCs could be recovered by switching the balance between Wnt and TGF-β signaling in vitro. Our findings provide a novel molecular pathogenic mechanism in which ectopic Wnt and TGF-β lead to DS physical dysplasia, suggesting potential targeted therapies for DS.

Neonatal mortality and morbidity in Down syndrome in the time of prenatal aneuploidy testing: a retrospective cohort study

The total uptake of prenatal aneuploidy screening for Down syndrome (DS) is increasing worldwide. As a result of increasing prenatal diagnosis of DS and subsequent termination of pregnancy, livebirth prevalence of DS is decreasing. The aim of this study is to explore the impact of an increasing uptake of prenatal aneuploidy screening on the neonatal mortality and morbidity in DS. This is a retrospective cohort study of 253 neonates with DS born between 2012 and 2018 that were seen at the outpatient clinic of five hospitals in the Netherlands. The medical files were reviewed for maternal and neonatal characteristics and neonatal morbidities. The Dutch national birth registry (Perined) provided mortality numbers of neonates with DS. The results were interpreted in the context of other published studies. Neonatal mortality in DS remained stable, ranging from 1.4 to 3.6%. A congenital heart defect (CHD) was found in 138 of the 251 neonates (55.0%) with atrial septal defect, atrioventricular septal defect, and ventricular septal defect being the most common. The type of CHD in DS did not change over time. Gastro-intestinal defects were present in 22 of the 252 neonates with DS (8.7%), with duodenal atresia as the most reported anomaly. Persistent pulmonary hypertension of the neonate (PPHN) was found in 31 of the 251 infants (12.4%). Conclusions: Although uptake of prenatal aneuploidy screening increased, neonatal mortality and morbidity in DS appears to be stable. An increased incidence of PPHN was found.What is Known:• The total uptake of prenatal aneuploidy screening for Down syndrome is increasing worldwide.• As a result of increasing prenatal diagnosis of Down syndrome and subsequent termination of pregnancy, the livebirth prevalence of Down syndrome is decreasing.What is New:• Although uptake of prenatal aneuploidy screening increased, neonatal mortality and morbidity in Down syndrome appears to be stable.• An increased incidence of persistent pulmonary hypertension of the neonate was found.

Chromosome silencing invitro reveals trisomy 21 causes cell-autonomous deficits in angiogenesis and early dysregulation in Notch signaling.

SUMMARYDespite the prevalence of Down syndrome (DS), little is known regarding the specific cell pathologies that underlie this multi-system disorder. To understand which cell types and pathways are more directly affected by trisomy 21 (T21), we used an inducible-XIST system to silence one chromosome 21 in vitro. T21 caused the dysregulation of Notch signaling in iPSCs, potentially affecting cell-type programming. Further analyses identified dysregulation of pathways important for two cell types: neurogenesis and angiogenesis. Angiogenesis is essential to many bodily systems, yet is understudied in DS; therefore, we focused next on whether T21 affects endothelial cells. An in vitro assay for microvasculature formation revealed a cellular pathology involving delayed tube formation in response to angiogenic signals. Parallel transcriptomic analysis of endothelia further showed deficits in angiogenesis regulators. Results indicate a direct cell-autonomous impact of T21 on endothelial function, highlighting the importance of angiogenesis, with wide-reaching implications for development and disease progression.

The Relationship Between Health System Functions and the Prevalence of Down Syndrome on a Global Scale

Objective: Down syndrome or trisomy 21 is one of the most common human chromosomal disorders that affect cognitive functions, communication and behavioral skills. At the macro level, various factors can contribute to the Down syndrome prevalence and mortality. This study aimed to investigate the association of health system functions with Down syndrome prevalence and mortality worldwide. Materials & Methods: The study was a cross-sectional study conducted based on the secondary analysis of existing data in 2019. Data from 202 countries in six different regions (African Region [AFRO], Eastern Mediterranean Region [EMRO], European Region [EURO], South-East Asia Region [SEARO], Western Pacific Region [WPRO], and Pan American Health Organization [PAHO]) were included in the study. Data were extracted from the World Health Organization (WHO), the World Bank and the Institute for Health Metrics and Evaluation databases. The adjusted linear regression analysis was used to examine the association between health system-related factors with prevalence of, and death due to Down syndrome as the outcome variables. In the present study, two functions of health financing (domestic general government health expenditure [GGHE-D] per capita in PPP [purchasing power parity] int$, domestic private health expenditure [PHE-D] per capita in PPP int$, external health expenditure [EXT] per capita in PPP int$) and health system resources (nurse and midwifery personnel, generalist medical practitioners [GMP], specialist medical practitioners [SMP], pharmacists, dentists, physiotherapists) were included in the study as independent variables. We used the Stata software version 14 to analyze Results: Africa and low-income countries had the highest deaths due to Down syndrome. On the other side, Europe and high-income countries had the highest prevalence of Down syndrome worldwide. According to the available data, Iran had a lower prevalence (29.31 vs 38.44 per 100,000 population) and higher deaths (0.34 vs 0.32 per 100,000 population) compared to high- income countries. The 20-year trend of prevalence of, and deaths due to Down syndrome in Iran has always been lower and higher than high-income countries, respectively. Linear regression analysis showed that GGHE-D per capita (β=0.385, P<0.001) and PHE-D per capita (β=0.354, P=0.02) could predict the prevalence of Down syndrome significantly in the study countries. On the other hand, nurse and midwifery personnel (β=-0.607, P=0.014) and number of SMP (β=0.420, P=0.025) were associated with increased deaths from Down syndrome in the included countries. Conclusion: Our findings showed GGHE-D and PHE-D are associated with a higher prevalence of Down syndrome in health systems. On the other hand, health system resources (nurses and SMP) were the main predictors of death due to Down syndrome in the included countries. International organizations and governments need to monitor and improve the equitable access of vulnerable groups to health services in low-income countries. Improving health insurance coverage and equitable distribution of health resources is suggested to reduce deaths due to Down syndrome in Iran.

Increased referrals for congenital hyperinsulinism genetic testing in children with trisomy 21 reflects the high burden of non-genetic risk factors in this group.

BackgroundHyperinsulinism results from inappropriate insulin secretion during hypoglycaemia. Down syndrome is causally linked to a number of endocrine disorders including Type 1 diabetes and neonatal diabetes. We noted a high number of individuals with Down syndrome referred for hyperinsulinism genetic testing, and therefore aimed to investigate whether the prevalence of Down syndrome was increased in our hyperinsulinism cohort compared to the population.MethodsWe identified individuals with Down syndrome referred for hyperinsulinism genetic testing to the Exeter Genomics Laboratory between 2008 and 2020. We sequenced the known hyperinsulinism genes in all individuals and investigated their clinical features.ResultsWe identified 11 individuals with Down syndrome in a cohort of 2011 patients referred for genetic testing for hyperinsulinism. This represents an increased prevalence compared to the population (2.5/2011 expected vs. 11/2011 observed, p = 6.8 × 10−5). A pathogenic ABCC8 mutation was identified in one of the 11 individuals. Of the remaining 10 individuals, five had non‐genetic risk factors for hyperinsulinism resulting from the Down syndrome phenotype: intrauterine growth restriction, prematurity, gastric/oesophageal surgery, and asparaginase treatment for leukaemia. For five individuals no risk factors for hypoglycaemia were reported although two of these individuals had transient hyperinsulinism and one was lost to follow‐up.ConclusionsDown syndrome is more common in patients with hyperinsulinism than in the population. This is likely due to an increased burden of non‐genetic risk factors resulting from the Down syndrome phenotype. Down syndrome should not preclude genetic testing as coincidental monogenic hyperinsulinism and Down syndrome is possible.

Gastrostomy Tube Placement and Resource Use in Neonatal Hospitalizations With Down Syndrome.

To determine the trends in gastrostomy tube (GT) placement and resource utilization in neonates ≥35 weeks' gestational age with Down syndrome (DS) in the United States from 2006 to 2017. This was a serial cross-sectional analysis of neonatal hospitalizations of ≥35 weeks' gestational age with International Classification of Diseases diagnostic codes for DS within the National Inpatient Sample. International Classification of Diseases procedure codes were used to identify those who had GT. The outcomes of interest were the trends in GT and resource utilization and the predictors of GT placement. Cochran-Armitage and Jonckheere-Terpstra trend tests were used for trend analysis of categorical and continuous variables, respectively. Predictors of GT placement were identified using multivariable logistic regression. P value <.05 was considered significant. Overall, 1913 out of 51 473 (3.7%) hospitalizations with DS received GT placement. GT placement increased from 1.7% in 2006 to 5.6% in 2017 (P <.001), whereas the prevalence of DS increased from 10.3 to 12.9 per 10 000 live births (P <.001). Median length of stay significantly increased from 35 to 46 days, whereas median hospital costs increased from $74 214 to $111 360. Multiple comorbidities such as prematurity, sepsis, and severe congenital heart disease were associated with increased odds of GT placement. There was a significant increase in GT in neonatal hospitalizations with DS, accompanied by a significant increase in resource utilization. Multiple comorbidities were associated with GT placement and the early identification of those who need GT could potentially decrease length of stay and resource use.

RAPID DETECTION OF DOWN SYNDROME BY SHORT TANDEM REPEAT ANALYSIS FROM EASTERN INDIA

Down syndrome (DS) is the most common chromosomal disorder in human, caused by an extra copy of chromosome 21(Ward et al. 1999). It constitutes the most frequent form of intellectual disability. The cytogenetic prole of down syndrome includes trisomy 21, Robertsonian translocations, mosaicism, duplication of the critical region and other structural rearrangement involving chromosome 21(Verma et al. 1998,). India has the highest number of people suffering from DS in the world (Sherman et al 2007). The high prevalence is mainly due to lower level of care considered for 2/3 of Down syndrome pregnancies that are under 35 years of mother age and low level of information behind etiology of Down syndrome for instance about advanced maternal age(Van Montfrans et al. 2002). To reduce signicantly the birth prevalence of Down syndrome, a wide-ranging screening of pregnant women has been suggested (Pertl et al. 1996). However, conventional methods such as cytogenetic analysis for diagnosis of chromosomal abnormalities often need lengthy laboratory procedures, and expertise, are expensive as well as signicant delay in obtaining a diagnosis (Patterson et al. 2005). Applying of uorescence in situ hybridization technique from late 1980s using uorescently labeled DNA probe has facilitated analysis of chromosome abnormalities. However, genotyping of short tandem repeats (STR) on chromosome 21 is an alternative rapid inexpensive &amp; reliable method for the identication of DS child and is also even suitable for large scale screening of pregnant women (Rahil et al. 2002). The STRs are the hypervariable regions of the genome with variable repeat length and can be used for the quantitative analysis of extra chromosome of 21. This study aims to identify the DS child using simple PCR based analysis of STR markers on chromosome 21 among the eastern Indian population.

Down syndrome: a review of ocular manifestations.

Down syndrome is the most common genetically mediated intellectual disability. Although many physiologic and pathologic features of Down syndrome are discussed at length in the literature, the ocular manifestations of Down syndrome have seldom been discussed in a comprehensive fashion. Given that Down syndrome has ocular manifestations from the front to the back of the eye, it is important for physicians to become familiar with these manifestations, especially given the prevalence of Down syndrome. This review aims to discuss the varied ophthalmologic manifestations of Down syndrome – including strabismus, amblyopia, nystagmus, accommodation deficits, nasolacrimal duct obstruction, keratoconus, optic nerve pathology, neoplastic disease, and retinal pathology – to facilitate better care and visual outcomes in this important patient population.

Co-occurrence of congenital anomalies by maternal race/ethnicity among infants and fetuses with Down syndrome, 2013-2017: A U.S. population-based analysis.

Individuals with Down syndrome (DS) have a higher prevalence of additional congenital anomalies, especially cardiovascular defects, compared to the general population. Several reports have indicated that the prevalence of DS among live births varies by race and ethnicity within the United States. We aim to examine variations in co-occurring congenital anomalies by maternal race/ethnicity among infants and fetuses diagnosed with DS born during 2013-2017. State birth defect surveillance systems (N= 12) submitted data on infants and fetuses diagnosed with DS born during 2013-2017. We calculated the prevalence of co-occurring major and minor congenital anomalies, by organ system, and four selected cardiovascular birth defects, all stratified by maternal race/ethnicity. Among 5,836 cases of DS, 79.7% had one or more co-occurring congenital anomalies. There was a higher percentage of co-occurring congenital anomalies among infants and fetuses born to Hispanic mothers. The lowest percentage of co-occurring congenital anomalies, including three out of the four individual cardiovascular conditions examined, was among infants/fetuses born to non-Hispanic American Indian/Alaska Native mothers. We describe differences in DS co-occurrence with additional congenital anomalies among maternal racial/ethnic groups. These data may help focus future research on differences among racial/ethnic groups in the diagnosis and reporting of co-occurring congenital anomalies in infants/fetuses diagnosed with DS.

Combined First-trimester Screening of Trisomy 21 in Women of Different Ages in Southwest Iran

Background: There is evidence that the incidence of trisomy 21 has a direct linear relationship with maternal age, and older women are at a higher risk for giving birth to neonates with Down syndrome (DS). Objectives: The present study aimed to evaluate the performance and effectiveness of combined first-trimester screening (FTS) for DS in women of different ages in Southwest Iran. Methods: In this cross-sectional study, FTS was conducted on 7192 pregnant women in the 11th to 13th week of gestational age, referred to the Narges Medical Genetics and Prenatal Diagnosis Laboratory, Ahvaz, Iran. Amniocentesis and cytogenetic analysis were performed in all women with an estimated risk of 1 in 100 and above. Results: The FTS detection rate of DS was 83.3%, with the false positive rates of 2.1% and 13.5% in young women and those over 35 years, respectively. A significant correlation (r = 0.137, P &lt; 0.001) was observed between the high risk of DS (1:100) and maternal age. The high risk of DS was found to be higher in women over 35 years of age than those under 35 years old (6.67% vs. 1.95%). Total DS prevalence was 2.64 per 1000 cases. The prevalence of DS in women under and over 35 years of age was 1.95 and 6.67 per 1000 pregnancies, respectively. Conclusions: First-trimester screening is an effective method for estimating the risk of DS in women under or over 35 years of age. Although an advanced maternal age is associated with a higher prevalence of DS, clinicians should recommend FTS as the first-line screening method regardless of maternal age.

Does non-invasive prenatal testing affect the livebirth prevalence of Down syndrome in the Netherlands? A population-based register study.

ObjectiveTo evaluate if non‐invasive prenatal testing (NIPT) affects livebirth (LB) prevalence of Down syndrome (DS) in the Netherlands.MethodData from clinical genetics laboratories and the Working Party on Prenatal Diagnosis and Therapy (2014–2018) and previous published data (1991–2013) were used to assess trends for DS LB prevalence and reduction percentage (the net decrease in DS LBs resulting from selective termination of pregnancies). Statistics Netherlands provided general population data.ResultsDS LB prevalence increased from 11.6/10,000 in 1991 to 15.9/10,000 in 2002 (regression coefficient 0.246 [95% CI: 0.105–0.388; p = 0.003]). After 2002, LB prevalence decreased to 11.3/10,000 in 2014 and further to 9.9/10,000 in 2018 (regression coefficient 0.234 (95% CI: −0.338 to −0.131; p < 0.001). The reduction percentage increased from 26% in 1991 to 55.2% in 2018 (regression coefficient 0.012 (95% CI: 0.010–0.013; p < 0.001)). There were no trend changes after introducing NIPT as second‐tier (2014) and first‐tier test (2017).ConclusionsIntroducing NIPT did not change the decreasing trend in DS LB prevalence and increasing trend in reduction percentage. These trends may be caused by a broader development of more prenatal testing that had already started before introducing NIPT.

Demographic Assessment of Down Syndrome: A Systematic Review.

The objective of this study is to assess the evidence about the demographic transformation of the Down Syndrome population, with a specific focus on prenatal testing, and to identify sources frequently used for demographic assessment of Down Syndrome in the world. We reviewed existing studies on demographic transformations in the population with Down Syndrome, specifically birthrate indicators, under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. The searches were made in Medline (via EBSCO Host), Academic Search Complete (via EBSCO Host), PsycINFO (via EBSCO Host), Web of Science (Core Collection), Public Health Database (via ProQuest), and The Cochrane Library. The terms were developed through Medical Subject Headings (MESH) and American Psycological Asociation Thesaurus of Psychological Index Terms (APA). Full texts were reviewed if information was given regarding location and birthrate for a range of three years or more, and if the first and last year considered was within 1960 and 2019. We found 22 references with a period of study between 1960 and 2019 following the global spread of prenatal testing for Down Syndrome. We found a consistent association between prenatal diagnosis and birthrate, enough to explain the significant fall in the prevalence of Down Syndrome, a somewhat rising incidence of Down Syndrome related to increased maternal age and extension of fertility services in healthcare systems, a generalized use of specific congenital birth defect registries as the primary source of data, and an unclear influence of socio-cultural and territorial variables. Our findings can inform research, policy, and practice to improve the reproductive health and quality of life of the population with Down Syndrome.