Diagnosis Of Down Syndrome Research Articles

The Ups and Downs of Down Syndrome: A Qualitative Study of Positive and Negative Parenting Experiences

The current study sought to expand current literature by providing a comparison of the positive and negative experiences reported by parents of children with a Down syndrome (DS) diagnosis. A total of 435 participants from a national study were included in the current qualitative analysis based on responses to online survey data from two research questions asking parents to describe their most positive and most negative experiences in parenting their child with DS. Positive experiences themes included the following: impact on parents and other people, child’s achievements, social acceptance/connection, and everyday/everything/many. Negative experiences themes included medical experiences, lack of social acceptance/connection, the DS diagnosis, and the impact on parents and other people. Implications for professionals and future research are presented.

Attitudes to prenatal screening among Norwegian citizens: liberality, ambivalence and sensitivity

BackgroundNorway’s liberal abortion law allows for abortion on social indications, yet access to screening for fetal abnormalities is restricted. Norwegian regulation of, and public discourse about prenatal screening and diagnosis has been exceptional. In this study, we wanted to investigate whether the exceptional regulation is mirrored in public attitudes.MethodAn electronic questionnaire with 11 propositions about prenatal screening and diagnosis was completed by 1617 Norwegian adults (response rate 8.5%).ResultsA majority of respondents supports increased access to prenatal screening with ultrasound (60%) and/or full genome sequencing of fetal DNA (55%) available for all pregnant women. Significant minorities indicate, however, that a public offer of prenatal screening for all pregnant women would signal that people with Down syndrome are unwanted (46%) or could be criticized for contributing to a ‘sorting society’ (48%).ConclusionsResults indicate deeper ambivalences and a cultural sensitivity to the ethical challenges of prenatal screening and subsequent abortions. The specific diagnosis of Down syndrome and the fear of becoming a ‘sorting society’ which sorts human life due to diagnoses, appear to play prominent roles in citizen deliberations. The low response rate means that a non-response bias cannot be excluded, yet reasons why results are still likely to be of value are discussed.

Health economic evaluation of five prenatal screening strategies for Down's syndrome

Objective To investigate the cost-effectiveness and cost-benefit of five screening strategies for Down syndrome (DS) to optimize prenatal screening strategy. Methods A retrospective analysis was conducted in 26 803 gravidas, who underwent the second trimester maternal serum screening ( maternal serum α-fetoprotein and β-human chorionic gonadotropin) from 2002 to 2003, whom were classified into three groups according to the results of serum DS screening: high risk group (≥1/270), borderline risk group (≥1/1 000-<1/270) and elderly gravida group (age at expected date of confinement≥35 years old). TreeAge Pro 2011 sofware was used to set up the decision tree model for cost-effectiveness and cost-benefit analysis. Strategy 1: Maternal serum screening was carried out on all gravidas, and then prenatal diagnosis was performed for women in high risk group. Strategy 2: Non-invasive prenatal testing (NIPT) was carried out on all gravidas, and then prenatal diagnosis was offered for women with positive or suspected results. Strategy 3: NIPT was only carried out on gravidas of advanced maternal age and maternal serum screening was performed on the rest population. Gravidas with positive or suspected positive results in NIPT or classified into the high risk group underwent prenatal diagnosis. Strategy 4: Maternal serum screening was carried out on all gravidas. Those at high risk received prenatal diagnosis, while those at borderline risk underwent NIPT first and followed by prenatal diagnosis if positive or suspected positive NIPT results were identified. Strategy 5: Maternal serum screening was carried out on all gravidas. Those at high or borderline risk would undergo NIPT followed by prenatal diagnosis if they were positive or suspected positive for NIPT. Results (1) Among 26 803 gravidas, 1 244 were at high risk group (4.64%) with five having trisomy 21; 3 925 were at bordelrine risk (14.64%) with four having trisomy 21; 300 women were of advanced age (1.12%) with one having trisomy 21. (2) Cost-effectiveness analysis: the incremental cost-effectiveness ratios of strategy 3 and 4 were negative and that of strategy 1 was 0 with a cost-effectiveness ratio of 15 833 764.53. The incremental cost-effectiveness ratio of strategy 2 was 49 865 746.10, which was far greater than that of strategy 5 (63 049.56). The cost-effectiveness ratio of strategy 4 is 586 703.63, which was less than those of strategy 1,2 and 3 but higher than that of strategy 5. The average cost-effectiveness ratio of strategy 5 was the lowest (508 431.20) among these five strategies, which meant that for every diagnosis of DS, strategy 5 had the lowest cost (508 400 yuan). (3) Cost-benefit analysis: The benefits of strategy 4 and 5 were greater than their costs. Strategy 5 had the highest benefit-cost ratio, followed by strategy 4, 2, 3 and 1. (4) When other factors remained unchanged and only the acceptance rate of prenatal diagnosis was adjusted from 50% to 100%, strategy 1 had the least cost expectation, followed by strategy 3, 5, 4 and 2. When the cost of NIPT was below 82.4 yuan, the cost expectation of strategy 2 that performed on all gravidas was the lowest, while when it was between 82.4 and 1 827.2 yuan, the screening cost of strategy 5 was the lowest. Conclusions Strategy 5 has the best cost-effectiveness and cost-benefit. It would be the best screening strategy for DS, if the cost of NIPT is between 82.4-1 827.2 yuan. Key words: Down syndrome; Neonatal screening; Prenatal diagnosis; Costs and cost analysis; Cost-benefit analysis; High-throughput nucleotide sequencing

‘Prenatal screaming’ decision-making following a prenatal diagnosis of Down syndrome

‘Prenatal screaming’ decision-making following a prenatal diagnosis of Down syndrome

Multicentre study “Prenatal diagnosis of Down syndrome in Russia 2005–2015”. II. Ultrasound markers

Objective: to study the effectiveness of the use of ultrasound markers for Down syndrome (DS) in the fetus during ultrasound examinations at 11–14 and 18–21 weeks of gestation based on the results of multicentre analysis in the regions of Russia in 2005–2015 years. Materials. The analysis was based on data from a questionnaire on prenatal diagnosis of DS in 30 regions and cities of Russia in 2015. The data from the questionnaire survey of 12 regions in 2005 and 23 regions in 2010 for analyse the dynamic of prenatal diagnosis of DS in our country was obtained. The questionnaire included the questions about the number of births and pregnant women registered in the region; the total number of cases of DS registered in prenatal and postnatal periods; structures of diagnosed cases of DS depending on the detection period; indications for prenatal karyotype; the number of fetuses with DS and the increase of nuchal translucency in 11–14 weeks of gestation; ultrasound markers of DS in the II trimester of gestation and perinatal outcome in cases of prenatal diagnosis of DS. Results. In the course of the multicentre analysis it was established that the accuracy of identification of DS in the prenatal period in our country was 30,9% in 2005, 38,4% in 2010 and significantly increased to 59,7% in 2015. In 2005, only 17,2% of cases of DS were detected in 11–14 weeks of gestation, in 2010 — 38,2% and increased to 72,1 % (7,6–100%) in 2015. In 24 from 30 regions the proportion of diagnosed cases of trisomy 21 at 11–14 weeks of gestation was 50% or more, and in 11 regions — 90–100%. Increase of nuchal translucency thickness was detected on average in 76,3 % fetuses with DS with a range from 28,1 to 100 %. The most prenatal ultrasound markers in fetuses with DS in the second-trimester were congenital malformations and hypoplasia / absence of nasal bones — 64,9 and 65,5 %, respectively. Further, as the frequency of detection decreased: prenasal thickness (27,6 %), echogenic intracardiac focus (27,1%), pyelectasis (22%), nuchal fold (19,7%), short humerus/femur (17,5%), hyperechogenic bowel (14,6%), ventriculomegaly (11,2%), choroid plexus cysts (7,3%). Conclusion. Ultrasound examination is powerful method for identification the fetuses with DS. Therefore, it is necessary to continue the development of new ultrasound markers of DS for improving its prenatal diagnosis.

Prevalence of Aging, Dementia, and Multimorbidity in Older Adults With Down Syndrome

ImportanceAs the life expectancy of people with Down syndrome (DS) has markedly increased over the past decades, older adults with DS may be experiencing a higher incidence of aging conditions. In addition to longevity, the amyloid precursor protein gene located on chromosome 21 places individuals with DS at a high risk for developing Alzheimer disease. Yet, few studies have determined prevalence of dementia and comorbidities among older people with DS.ObjectiveTo determine the prevalence of dementia and aging-related comorbidities in older adult individuals with DS.Design, Setting, and ParticipantsCross-sectional analysis of 2015 California Medicare claims data. We examined 1 year of cross-sectional Medicare claims data that included 100% of Californian Medicare beneficiaries enrolled in both Medicare Part A and B in 2015. Of these 3 001 977 Californian Medicare beneficiaries 45 years or older, 878 individuals were identified as having a diagnosis of DS. Data were analyzed between April 2017 and February 2018.Main Outcomes and MeasuresThe frequency of DS dementia was assessed across different age categories. The number and frequency of 27 comorbidities were compared among individuals with DS with and without dementia and by age and sex groups.ResultsA total of 353 DS individuals (40%) were identified as having dementia diagnoses (mean, 58.7 years; 173 women [49%]) and 525 without dementia diagnoses (mean, 55.9 years; 250 women [48%]). The frequency of DS dementia among those 65 years or older rose to 49%. The mean number of comorbidities per individual increased with age in general. Comorbid conditions were more numerous among those with dementia compared with those with DS without dementia (mean, 3.4 vs 2.5, respectively), especially among those younger than 65 years. In particular, 4 treatable conditions, hypothyroidism, epilepsy, anemia, and weight loss, were much more frequent in DS dementia.Conclusions and RelevanceOlder Medicare beneficiaries in California with DS, especially those with dementia, have a high level of multimorbidity including several treatable conditions. While DS follow-up has long been confined to the pediatric sphere, we found that longevity in individuals with DS will necessitate complex adult and geriatric care. More evidenced-based and standardized follow-up could support better long-term comorbidity management and dementia care among aging adults with DS.

'We would have missed out so much had we terminated': What fathers of a child with Down syndrome think about current non-invasive prenatal testing for Down syndrome.

Non-invasive prenatal testing (NIPT) allows early, accurate diagnosis of Down syndrome that has resulted in increased terminations. This qualitative study involved in-depth interviews of fathers of children with Down syndrome about their views on the availability of NIPT. Thematic network analysis revealed that although fathers appreciated an early diagnosis with NIPT, they saw the test as being a predetermined pathway to termination. Fathers felt that expectation to terminate reflects negative societal attitudes towards those with Down syndrome and disability, fearing that NIPT may become a form of eugenics. Fathers retrospectively contrasted these attitudes with the actual reality of raising their children with Down syndrome, which they described as bringing joy to their lives. Findings suggest that although fathers valued NIPT as an information-giving tool that allowed autonomous parental choices about the pregnancy, they believe that it should be accompanied by balanced information about the reality of raising a child with Down syndrome.

Termination of pregnancy following a prenatal diagnosis of Down syndrome: A qualitative study of the decision-making process of pregnant couples.

In Denmark, first trimester screening has a very high uptake (>90%). If Down syndrome is diagnosed, termination rates are high (>95%). The aim of this study was to investigate the timing of the decision to terminate pregnancy following a diagnosis of Down syndrome and the factors influencing this decision. Semi-structured, qualitative interview study with 21 couples who had received a prenatal diagnosis of Down syndrome and decided to terminate the pregnancy. Participants were recruited from obstetric departments between February 2016 and July 2017. Data were analyzed using thematic analysis. Five themes were identified: "initial decision-making", "consolidating the decision", "reasons and concerns shaping the termination of pregnancy decision", "the right decision is also burdensome", and "perceived influences in decision-making". For most couples, the initial decision to terminate pregnancy was made before or during the diagnostic process, but it was re-addressed and consolidated following the actual diagnosis. Imagining a family future with a severely affected Down syndrome child was the main factor influencing the termination of pregnancy decision. The decision was articulated as "right" but also as existentially burdensome for some, due to fear of regret and concern about ending a potential life. The decision to terminate pregnancy was considered a private matter between the couple, but was refined through interactions with clinicians and social networks. All couples made an initial decision prior to receiving the Down syndrome diagnosis. Knowledge of the couple's initial decision may facilitate patient-centered communication during and after the diagnostic process. Couples may benefit from counseling to deal with grief and existential concerns.

Supporting boys and girls with Down syndrome

This paper will address students who have the diagnosis of Down syndrome. It will encompass the overall understanding of what a child with Down syndrome experiences in and outside of the classroom, as well as some of the physical characteristics that can manifest as a result of a genetic mutation resulting in the diagnosis of Down syndrome.

Maternal Considerations to Termination of Down Syndrome Pregnancies [10L

INTRODUCTION: To assess maternal factors that influence a patient's decision to terminate a pregnancy affected by Down syndrome. METHODS: This retrospective study included all patients diagnosed with fetal Down syndrome via amniocentesis between 1990 and 2006 at the University of Iowa Hospital and Clinics. Patients were stratified into two groups by maternal age and socio-clinical data were collected from initiation of prenatal care to the end of the pregnancy. RESULTS: Total of 261 patients were diagnosed with Down syndrome fetuses, 106 (40.6%) of which belonged to women &lt;35 years old and 155 (59.4%) to &gt;35 year old. Fifty pregnancies (47.2%) in the former group were terminated while 107 (69.0%) were terminated for the latter. Patients &gt;35 yo were diagnosed at a significantly earlier gestational age compared to those &lt;35 yo (16.8+1.9 versus 18.9+2.9, P&lt;.03). Older patients also had a longer time period from diagnosis to termination than younger patients (2.5 versus 2.0 weeks). CONCLUSION: Few studies have focused on the patient who must make the ultimate decision on her pregnancy in face of a positive amniocentesis for Down syndrome. We found that the key difference between older women who chose termination compared to those &lt;35 yo is an earlier gestational age at amniocentesis, with a longer period available for decision making. This stresses the importance of availability of screening programs for early karyotyping and diagnosis of Down syndrome and early education.

Prenatal diagnosis of Down syndrome

Down syndromes are the most commonly recognized genetic cause of mental retardation. The risk of trisomy 21 is directly related to maternal age, neuchal translucency, nasal bone, tricuspid valve regurgitation and fetal heart rate. Also, maternal serum markers must be included to increase the sensitivity and specificity of the ultrasound screening of Down syndrome.

Application of droplet digital PCR for prenatal screening of Down syndrome

Background: This study was proposed to explore the feasibility of droplet digital PCR (ddPCR) analysis for non-invasive prenatal diagnosis of Down syndrome. Materials and Methods: The authors studied maternal plasma samples from 465 pregnant women carrying euploid and trisomy 21 (T21) fetuses. A methylation-sensitive restriction endonuclease, BstUI, was used to digest the hypomethylated holocarboxylase synthetase (HLCS) gene. The authors quantified digestion-resistant HLCS gene on chromosome 21 and fetal-specific rs6636 SNP allele on chromosome 14 by droplet digital PCR analysis. Maternal plasma DNA analysis was performed by comparing the ratio of hypermethylated HLCS to fetal-specific rs6636 SNP allele between two groups. Results: Using a rs6636 SNP allele on chromosome 14 as the reference marker, the authors analyzed 78 euploid and 28 T21 plasma samples. The ratios of the numbers of positive hypermethylated HLCS and the fetal-specific C allele in the euploid and T21 samples were significantly different ( p p Conclusions: The study demonstrated that ddPCR approach can be applied for prenatal screening of trisomy 21.

MicroRNA Expression Profile in the Prenatal Amniotic Fluid Samples of Pregnant Women with Down Syndrome.

Background:Down syndrome, which is the most common human chromosomal anomaly that can affect people of any race and age, can be diagnosed prenatally in most cases. Prenatal diagnosis via culture method is time-consuming; thus, genetic analysis has thus been introduced and is continually being developed for rapid prenatal diagnosis. For this reason, the effective use of microRNA profiling for the rapid analysis of prenatal amniotic fluid samples for the diagnosis of Down syndrome was investigated.Aims:To evaluate the expression levels of 14 microRNAs encoded by chromosome 21 in amniotic fluid samples and their utility for prenatal diagnosis of Down syndrome.Study Design:Case-control study.Methods:We performed invasive prenatal testing for 56 pregnant women; 23 carried fetuses with Down syndrome, and 33 carried fetuses with a normal karyotype. Advanced maternal age and increased risk for Down syndrome in the screening tests were indications for invasive prenatal testing. The age of gestation in the study and control groups ranged between 17 and 18 weeks. The expression levels of microRNA were measured by real-time polymerase chain reaction.Results:The expression levels of microRNA-125b-2, microRNA-155, and microRNA-3156 were significantly higher in the study group than in the control group.Conclusion:The presence of significantly dysregulated microRNAs may be associated with either the phenotype or the result of abnormal development. Further large-scale comparative studies conducted in a variety of conditions may bring novel insights in the field of abnormal prenatal conditions.

Segmental duplication-quantitative fluorescent-polymerase chain reaction: An approach for the diagnosis of Down syndrome in India.

Objective:Early detection of high-risk pregnancies for Down syndrome (DS) is the main target of offering prenatal diagnosis. Segmental duplication-quantitative fluorescent-polymerase chain reaction (SD-QF-PCR) can be used as an alternative method for prenatal diagnosis of DS. SD-QF-PCR involves SD sequences between the test and control chromosomes to detect aneuploidies. SD are two similar sequences with different fragment lengths, located on two different chromosomes. When these SD regions are amplified, the peak ratio between the two different chromosomes remains as 0.9 to 1.1 and the trisomy 21 results in the ratio of 1.4 to 1.6.Materials and Methods:In this study, we applied SD-QF-PCR to detect the presence of trisomy 21 in 60 age-matched controls and 60 DS samples. The PCR amplification of SD regions is performed using a single pair of fluorescent-labelled primers, the peak ratio between the two different chromosome regions are evaluated.Results:All sixty control samples showed the peaks to range from 0.9 to 1.1, which was suggestive of normal samples, and peaks of 65 DS samples ranged from 1.4 to 1.6, which suggested the presence of trisomy 21.Conclusion:Segmental duplication quantitative fluorescent PCR is a sensitive and rapid aneuploidy detection technique and hence can be used as a standalone test to detect trisomy 21 as well as other aneuploidies.

Cross-cultural adaptation to the Brazilian Portuguese language of the Waisman Activities of Daily Living (W-ADL) for adolescents and adults with developmental disabilities

Waisman Activities of Daily Living (W-ADL) is a free and brief measure of activities daily living (ADL) for adolescents and adults with developmental disabilities. However, its use is limited in non-English-speaking countries. For this reason, translation, cross-cultural adaptation, and validation for other languages are needed. Thus, this study aimed to perform a translation and cross-cultural adaptation and validation of the W-ADL from English to Portuguese language. We used a rigorous approach for translating and adapting the scale, which included a committee of six experts to assess content validity. We also conducted interviews with 62 caregivers of people with a medical diagnosis of Autism spectrum disorder (ASD) or Down syndrome (DS) with different age groups who responded about the person with ASD or DS in their care. Our results include all steps from the translation and cross-cultural adaptation process. Item Content Validity Index showed that items 5 and 16 showed values not acceptable in “relevance” and “theoretical dimension”. On the other hand, the scale content validity index indicated acceptable value. Furthermore, our results showed that our version had acceptable reliability, did not presented floor and ceiling effects, and was able to discriminate subjects from different age groups, as expected. In conclusion, the two versions of the Portuguese version of the W-ADL Scale (15 items and 17 items) demonstrated the acceptable validity and reliability measurement to evaluate ADL for adolescents and adults with developmental disabilities. However, the 15-item version seems to be the best option for Portuguese language speakers.

Modified methylated DNA immunoprecipitation protocol for noninvasive prenatal diagnosis of Down syndrome.

Methylated DNA immunoprecipitation real-time quantitative polymerase chain reaction (MeDIP-real-time qPCR) has been introduced as noninvasive prenatal test that has shown absolute detection rate in the screening of Down syndrome. Herein, we aimed to propose a novel modification of MeDIP-qPCR and assess its potential to alleviate the overall cost of the test, being used in very early weeks of pregnancy, and develop it to a noninvasive prenatal diagnosis biosensor in future researches. Cell-free fetal DNA (cffDNA) isolated from 60 pregnant women, including 29 normal and 31 trisomy 21 pregnancies, were analyzed using proposed MeDIP protocol. Enriched methylated DNA sequences were amplified through real-time qPCR using eight fetal-specific primer pairs. The status of samples was determined through the calculation of D-value with the cutoff point of zero. The sensitivity and specificity of the MeDIP protocols using nanoparticles were 100% and 100%, respectively. Remarkable decrease in the price of MeDIP test per each patient would be a reasonable factor to confirm it on larger sample size. Moreover, the high detection rate of screening and the availability of the required instruments around the world make satisfactory reasons to be tested in earlier weeks of pregnancy, thanks to the high sensitivity of gold shell nanoparticles.

National screening guidelines and developments in prenatal diagnoses and live births of Down syndrome in 1973-2016 in Denmark.

Denmark was the first country in the world to implement a national, free-for-all offer of prenatal screening for Down syndrome to all pregnant women. It has a high uptake (>90%) compared to other countries. Thus, Denmark offers an interesting case for investigating the consequences of implementing comprehensive, national prenatal screening guidelines. The aim of this study was to describe the historical developments in invasive procedures, pre-/postnatal diagnoses of Down syndrome and Down syndrome live births in the period 1973-2016 in Denmark. Data on invasive procedures, pre- and postnatal Down syndrome diagnoses were retrieved from the Danish Cytogenetic Central Registry. From 1973 to 1993, screening based on maternal age and high-risk indications resulted in a constant increase in invasive procedures. After the introduction of the triple test in 1994, invasive procedures decreased for the first time in 20years. Following the introduction of an offer of combined screening to all pregnant women in 2004, the number of invasive procedures decreased markedly, while there was a concurrent increase in prenatal diagnoses of Down syndrome. Additionally, the number of Down syndrome live births decreased suddenly and significantly, but subsequently stabilized at 23-35 annual live births. Of these, the majority were diagnosed postnatally. Though prenatal screening technologies constantly improve, it was the introduction of and adherence to national guidelines that resulted in marked shifts in screening procedures and outcome in Denmark.

Association between DSCR4 gene methylation in plasma in early pregnancy and Down's syndrome.

Down's syndrome (DS), a chromosomal abnormal genetic disease caused by a local or total copy of chromosome 21, leads to patients suffering from delayed body growth, special facies, mild to moderate mental retardation and other symptoms, seriously affecting the life of patients. The aim of the present study was to examine the association between Down's syndrome critical region 4 (DSCR4) gene methylation in plasma in high-risk pregnant women with DS in early pregnancy (hereinafter referred to as pregnant women in early pregnancy) and DS, in order to screen new epigenetic markers for the clinical diagnosis of DS. DNA in peripheral blood cells and plasma in pregnant women in early pregnancy were treated with hydrosulphite. DSCR4 genes with different methylation levels were amplified by methylation-specific polymerase chain reaction (PCR), and the methylation difference of the CpG site of the DSCR4 amplification product in peripheral blood DNA was verified via restriction endonuclease analysis. The expression of DSCR4 with different methylation levels in peripheral blood of pregnant women in early pregnancy were detected via reverse transcriptase-quantitative PCR (RT-qPCR), and the DSCR4 gene functions were studied via the intervention in DSCR4 expression with small interfering RNA (siRNA). Methylation-specific PCR and restriction endonuclease analysis revealed that DSCR4 genes were differentially methylated in peripheral blood DNA in pregnant women in early pregnancy. Additionally, DSCR4 showed a low methylation status in plasma but a high methylation status in peripheral blood cells. RT-qPCR revealed that non-methylated DSCR4 was highly expressed in the peripheral blood of pregnant women in early pregnancy, and thus was an epigenetic marker of fetal DS. siRNA results showed that the downregulation of DSCR4 inhibited cell migration and invasion, but had no effect on cell proliferation. The results suggest that the DSCR4 gene was differentially methylated in peripheral blood DNA in pregnant women in early pregnancy. Furthermore, DSCR4 exists in a non-methylated state in plasma and in a hyper-methylated state in blood cells. DSCR4 can therefore promote the migration and invasion of trophocytes and serve as an epigenetic marker of non invasive clinical diagnosis of DS.

Chromosomal Abnormalities in Patients with Intellectual Disability: A 21-Year Retrospective Study

Background: Intellectual disability (ID) has been defined as a considerably reduced ability to understand new or complex information and to learn new skills. It is associated with life-long intellectual and adaptive functioning impairments that have a profound impact on individuals, families, and society. It affects about 3% of the general population. ID often comes out with other mental conditions like attention deficit, hyperactivity, and autism spectrum disorders (ASD), and it can be part of a malformation syndrome that affects other organs. It may be syndromic (S-ID) or non-syndromic (NS-ID). Objective: The aims of this study were to identify the profile of intellectually disable patients being referred for cytogenetic analysis in Morocco, to determine the prevalence of chromosomal abnormalities in a Moroccan group, and to compare the results with those of analogous studies from other countries. Participants: We included data from Moroccan patients with NS-ID and others with S-ID (mostly Down syndrome cases) who have been referred between 1996 and 2016. 1,626 patients were involved in this study, 1,200 were referred with a clinical diagnosis of Down syndrome, 37 were clinically diagnosed for ASD with ID, and 389 were suspected of NS-ID. Results: We identified 1,200 cases of Down syndrome. In 1,096 analyses (91.3%), a cytogenetic variant of trisomy 21 was identified: standard trisomy 21 in 1,037 cases (94.6%), a translocation in 34 cases (3.10%), and mosaicism in 25 cases (2.3%). The cytogenetic analysis among ASD with ID cases did not reveal any specific chromosomal abnormalities. The present study also shows that chromosomal abnormalities were present in 6.43% of the patients with NS-ID (25 abnormal karyotypes out of 389 NS-ID cases). Autosomal structural abnormalities were the largest proportion of chromosomal aberrations. Conclusion: The high rate of chromosomal abnormalities found in the Moroccan patients studied demonstrates the capital importance of cytogenetic evaluation in patients who show ID or any clinical development abnormality.

Specificity and Sensitivity of NIPT for Prenatal Screening of Down Syndrome in 100 Pregnant Women from Tonekabon, Iran

Down syndrome is one of the most common genetic disorders, with a prevalence of one in 600 live births. There are numerous methods for diagnosis of this syndrome before birth such as non-invasive prenatal testing (NIPT). This test evaluates positive and negative predictive values of Down syndrome screening as well as determining the gender of the fetus. Data were collected from 100 pregnant women who visited obstetrics and gynecology clinic of Tonekabon Hospital, Tonekabon, Iran. The average age of pregnant women was 35.9 and the average gestational age was 12 to 13 weeks. About 40% of participating mothers had a history of previous pregnancies (32%), 45% of mothers had no history of live births and none of them had a family history of developing Down syndrome. According to the results, 56 percent of babies were male and 44 percent were female and none of the fetuses had Down syndrome. Results of the present study also indicated that NIPT sensitivity and specificity in the diagnosis of Down syndrome and also the baby's gender were 100%. The positive and negative predictive values were also 100% as well. This study has shown that NIPT as a diagnostic test is used to detect Down syndrome in all pregnancies, including high-risk pregnancies such as cases with high maternal age. Another important issue which has to be taken into account is a source of support such as Insurance coverage for the test.