BACKGROUND

Down syndrome or trisomy 21, the most common chromosomal disorder, results from the presence of a third copy of chromosome 21 and manifests as mild to moderate intellectual disability, growth retardation, congenital heart defects, gastrointestinal abnormalities, and characteristic facial features. Several methods have been used to screen for Down syndrome in the prenatal period, such as ultrasound, biomarkers, cell-free DNA testing, and combinations of these tests. A positive result from one or more of these screening tests signals the need for confirmatory karyotyping to clinch the diagnosis. Ultrasound between 11 to 14 weeks of gestation can evaluate nuchal translucency (NT) to screen for Down syndrome. During the second trimester, a triple or quadruple test can also be performed alone or in addition to NT to quantify Down syndrome risk. In limited resource settings however, only the measurement of NT via ultrasound can be performed since biomarker tests are either unavailable or inaccessible. While the diagnostic performance of NT measurement alone has been investigated in several observational studies, there is no consensus on its performance as a sole test to screen for Down syndrome.

To determine the diagnostic performance of NT during prenatal first-trimester ultrasound as a screening test for Down syndrome.

We performed a systematic search on the PubMed, ProQuest, and Cochrane Library databases for recent systematic reviews and meta-analyses that addressed the objective. The existing reviews found were then independently appraised by the two reviewers with the AMSTAR-2 checklist. To update the existing reviews, a systematic search was done in the same databases to identify additional primary diagnostic studies, which were appraised using the QUADAS-2 tool. Random-effects univariate meta-analysis and summary receiving operator curve (HSROC) analysis for the outcomes were performed using Review Manager version 5.4 and R version 4.2.2, respectively. Subgroup analysis was performed by stratifying the baseline risk of mothers for fetal anomaly as low- or high-risk. Highrisk mothers were defined as women with risk factors such as advanced age, positive serum screen, presence of other ultrasound anomalies, and history of previous fetus with anomaly.

We found 22 cohort studies (n=225,846) of women at low-risk for fetal anomaly. The pooled sensitivity was 67.8% (95% CI: 61.4%-73.6%, I2=70.4%) and specificity was 96.3% (95% CI: 95.5%-96.9%, I2=96.7%). For low-risk women, the overall certainty of evidence was low, due to different modes of verification and heterogeneity not completely explained by variability in baseline risk or cut-points. Seven studies (n=9,197) were on high-risk women. The pooled sensitivity was 62.2% (95% CI: 54.1%-69.7%, I2=38.8%) and specificity was 96.5% (95% CI: 93.6%-98.1%, I2=95.5%). For women at high-risk, the evidence was rated as moderate due to differential verification.

Our analysis showed that NT measured through first-trimester ultrasound is specific for Down syndrome but has low sensitivity. Despite this, it is a useful screening test for Down syndrome in low-resource settings where other strategies may not be available or accessible. Furthermore, interpretation of NT results must take into consideration its limited sensitivity as this may lead to missed cases.

Here, we report a previously unrecognized syndromic neurodevelopmental disorder associated with biallelic loss-of-function variants in the RBM42 gene. The patient is a 2-year-old female with severe central nervous system (CNS) abnormalities, hypotonia, hearing loss, congenital heart defects, and dysmorphic facial features. Familial whole-exome sequencing (WES) reveals that the patient has two compound heterozygous variants, c.304C>T (p.R102*) and c.1312G>A (p.A438T), in the RBM42 gene which encodes an integral component of splicing complex in the RNA-binding motif protein family. The p.A438T variant is in the RRM domain which impairs RBM42 protein stability in vivo. Additionally, p.A438T disrupts the interaction of RBM42 with hnRNP K, which is the causative gene for Au-Kline syndrome with overlapping disease characteristics seen in the index patient. The human R102* or A438T mutant protein failed to fully rescue the growth defects of RBM42 ortholog knockout ΔFgRbp1 in Fusarium while it was rescued by the wild-type (WT) human RBM42. A mouse model carrying Rbm42 compound heterozygous variants, c.280C>T (p.Q94*) and c.1306_1308delinsACA (p.A436T), demonstrated gross fetal developmental defects and most of the double mutant animals died by E13.5. RNA-seq data confirmed that Rbm42 was involved in neurological and myocardial functions with an essential role in alternative splicing (AS). Overall, we present clinical, genetic, and functional data to demonstrate that defects in RBM42 constitute the underlying etiology of a new neurodevelopmental disease which links the dysregulation of global AS to abnormal embryonic development.
Female ; Animals ; Mice ; Humans ; Child, Preschool ; Intellectual Disability/genetics* ; Heart Defects, Congenital/genetics* ; Facies ; Cleft Palate ; Muscle Hypotonia

Insomnia induced by mental retardation is related to the synergistic dysfunction of "shaoyang, sanjiao and haishi (the period of the day from 9 pm to 11 pm) " in pathogenesis. Based on "trinity theory of shaoyang, sanjiao and haishi ", the acupoints of hand and food shaoyang meridians on the head and face (Fengchi [GB 20], Sizhukong [TE 23] and Jiaosun [TE 20]) and those on the four limbs (Sanyangluo [TE 8], Zhongzhu [TE 3], Qiuxu [GB 40] and Xiaxi [GB 43]) are selected to regulate the pivot function of shaoyang. Front-mu and back-shu points (Sanjiaoshu [BL 22], Danzhong [CV 17] and Tianshu [ST 5]), as well as auricular points (Gan [CO₁₂], Dan [CO₁₁] and Sanjiao [CO₁₇]) are chosen to promote qi circulation of shaoyang and sanjiao meridians. In association with the relevant knowledge of time acupuncture at haishi, the circadian rhythm of sleep is set up and the appropriate sleep pattern is developed.
Humans ; Sleep Initiation and Maintenance Disorders/therapy* ; Intellectual Disability ; Acupuncture Therapy ; Meridians ; Acupuncture Points

Humans ; East Asian People ; Intellectual Disability/genetics* ; Membrane Transport Proteins/genetics* ; Lectins/genetics*

Child ; Humans ; Adolescent ; Cross-Sectional Studies ; Intellectual Disability ; Exercise

Objective To explore the clinical significance of non-invasive prenatal testing(NIPT)for fetal chromosomal abnormalities in the cases of twin pregnancy and its relationship with age and other related factors.Methods A total of 3733 women with twin pregnancy of 12-26⁺⁶ weeks who voluntarily underwent NIPT in the Ningbo Women and Children's Hospital from January 2018 to December 2022 were selected.The results of NIPT and amniocentesis were compared and all the participants were followed up.The detection rate of chromosomal abnormalities by NIPT was calculated,and its correlations with age,gestational weeks,chorionicity,and pregnancy type were analyzed.Results Among the 3733 cases,71 cases of fetal chromosome abnormality were indicated by NIPT,including 13 cases of trisomy 21,19 cases of trisomy 18,5 cases of trisomy 13,18 cases of sex chromosome abnormality,and 16 cases of chromosome microdeletion/duplication(excluding 21,18,13,and sex chromosomes),among which 34 cases were true positive and 37 cases were false positive.The overall sensitivity,specificity,and positive predictive value(PPV)of NIPT for chromosomal abnormalities in the cases of twin pregnancy were 100%,98.99%,and 47.89%(34/71),respectively.NIPT showed the sensitivity,specificity,and PPV of 100%,99.78%,and 78.38%(29/37)for trisomy 21,18,and 13,100%,99.56%,and 16.67%(3/18)for sex chromosome abnormalities,and 100%,99.62%,and 12.5%(2/16)for chromosome microdeletion/duplication,respectively.In the age group of ≥40 years,the NIPT for chromosomal abnormalities showed the PPV of 66.67%,the sensitivity of 100%,and the misdiagnosis rate of 30%。However,the NIPT for trisomy 21,18,and 13 showed the PPV of 100%,the misdiagnosis rate of 0,and the sensitivity and specificity of 100%.In terms of grouping based on gestational weeks,the NIPT for chromosomal abnormalities showed the highest PPV(51.28%)in the women with twin pregnancy for 14-17⁺⁶ weeks,followed by that(50.00%)in the women with twin pregnancy for 22-26⁺⁶ weeks;the NIPT for trisomy 21,18,and 13 showed the highest PPV of 94.74% in the gestation group of 14-17⁺⁶ weeks,followed by that(83.33%)in the gestation group of 18-21⁺⁶ weeks.The rate of dichorionic diamniotic twins was higher in assisted pregnancies than in natural pregnancies,and NIPT showed the same detection efficiency for dichorionic diamniotic twins and monochorionic diamniotic twins and the same detection efficiency for different pregnancy types.Conclusions NIPT has high accuracy in the diagnosis of twin pregnancy and high sensitivity and high specificity for different ages and gestational weeks,especially for trisomy 21,18,and 13.NIPT is suitable for assisted pregnancy and natural pregnancy,and it is of high value in clinical application.However,extensive application needs a large population-based study.
Pregnancy ; Child ; Female ; Humans ; Adult ; Down Syndrome/genetics* ; Pregnancy, Twin ; Prenatal Diagnosis ; Trisomy ; Chromosome Aberrations

OBJECTIVE: To assess the value of non-invasive prenatal testing (NIPT) for detecting fetal chromosomal microdeletion/microduplication syndromes by carrying out prenatal diagnoses for two fetuses with Xp22.31 microdeletion indicated by NIPT. METHODS: Two pregnant women suspected for fetal Xp22.31 microdeletion syndrome who presented at Zaozhuang Maternal and Child Health Care Hospital on December 5, 2017 and October 15, 2020 were selected as the study subjects. Clinical data of the two women were collected, and peripheral venous blood samples were collected for NIPT testing. Amniotic fluid samples were taken for G-banding chromosomal karyotyping analysis and copy number variation sequencing (CNV-seq) for fetus 1, while G-banding chromosomal karyotyping and single nucleotide polymorphism microarray analysis (SNP array) were carried out for fetus 2. Peripheral venous blood samples of couple 1 were collected for CNV-seq to verify the origin of copy number variation . RESULTS: NIPT indicated that fetus 1 had harbored a 1.3 Mb deletion in the Xp22.31 region, while G-banding chromosomal karyotyping had found no abnormality. CNV-seq analysis verified the fetus to be seg[GRCh37]del(X)(p22.31)chrX:g.6800001_7940000del, with a 1.14 Mb deletion at Xp22.31, which was derived from its mother. NIPT indicated that fetus 2 had harbored a 1.54 Mb deletion in the Xp22.31 region, while G-banding chromosomal karyotyping had found no abnormality. SNP array analysis indicated arr[GRCh37]Xp22.31(6458940_8003247)×0, with a 1.54 Mb deletion in Xp22.31 region. CONCLUSION NIPT not only has a good performance for detecting fetal trisomies 21, 18 and 13, but also has the potential for detecting chromosomal microdeletion/microduplications. For high risk fetuses indicated by NIPT, prenatal diagnosis needs to be carry out to verify the chromosomal abnormalities.
Child ; Female ; Pregnancy ; Humans ; DNA Copy Number Variations ; Prenatal Diagnosis ; Down Syndrome/diagnosis* ; Chromosome Aberrations ; Fetus

OBJECTIVE: To assess the value of non-invasive prenatal testing (NIPT) for trisomy 21 (T21), trisomy 18 (T18), trisomy 13 (T13), sex chromosome aneuploidies, chromosomal microdeletions and microduplications using cell-free fetal DNA from peripheral blood samples of pregnant women. METHODS: A total of 15 237 pregnant women who had undergone NIPT testing at the Maternity and Child Health Care Hospital of Zaozhuang from February 2015 to December 2021 were enrolled in this study. For those with a high risk by NIPT, amniotic fluid samples were collected for G-banding chromosomal karyotyping analysis and chromosomal microarray analysis to verify the consistency of NIPT with results of prenatal diagnosis. All of the women were followed up by telephone for pregnancy outcomes. RESULTS: Among the 15 237 pregnant women, 266 (1.75%) were detected with a high risk for fetal chromosomal abnormality were detected. Among these, 79 (29.7%) were at a high risk for T21, 26 (9.77%) were at a high risk for T18, 9 (3.38%) were at a high risk for T13, 74 (27.82%) were at a high risk for sex chromosome aneuploidies, 12 (4.51%) were at a high risk for other autosomal aneuploidies, and 66 (24.81%) were at a high risk for chromosomal microdeletions or microduplications. 217 women had accepted invasive prenatal diagnosis and respectively 50, 13, 1, 25, 1 and 18 were confirmed with T21, T18, T13, sex chromosome aneuploidies, autosomal aneuploidies and microdeletions/microduplications, and the positive predictive values were 75.76%, 68.42%, 11.11%, 40.32%, 10% and 35.29%, respectively. For 13 042 women (85.59%), the outcome of pregnancy were successfully followed up. During the follow-up, one false negative case of T21 was discovered. No false positive cases for T13 and T18 were found. CONCLUSION NIPT has a sound performance for screening T13, T18 and T21, and is also valuable for screening other autosomal aneuploidies, sex chromosome aneuploidies and chromosomal microdeletions/microduplications.
Child ; Female ; Pregnancy ; Humans ; Retrospective Studies ; Cell-Free Nucleic Acids ; Chromosome Disorders/genetics* ; Prenatal Diagnosis/methods* ; Down Syndrome/genetics* ; Sex Chromosome Aberrations ; Trisomy 18 Syndrome/genetics* ; Trisomy 13 Syndrome/diagnosis* ; Aneuploidy ; DNA/genetics* ; Trisomy/genetics*

OBJECTIVE: To investigate the clinical phenotype and genetic characteristics of a Chinese pedigree affected with Cohen syndrome. METHODS: A proband who was admitted to Zhengzhou People's Hospital on June 2, 2021 due to intellectual disability and developmental delay, in addition with her younger sister and other family members, were selected as the study subjects. Clinical data of the proband and her younger sister were collected. Genomic DNA was extracted from peripheral venous blood and chorionic villi samples. Chromosomal abnormalities were detected with chromosomal microarray analysis (CMA). Whole exome sequencing (WES) and Sanger sequencing were carried out to detect candidate variants in the proband. With RNA extracted from the peripheral blood samples, VPS13B gene transcripts and expression were analyzed by PCR and real-time quantitative PCR. Prenatal diagnosis was carried out at 12 weeks' gestation. RESULTS: The proband was a 10-year-old female with clinical manifestations including development delay, obesity, severe myopia and peculiar facial features. Her sister was 3 years old with a similar phenotype. CMA revealed no chromosomal abnormality in the proband, while WES results revealed that the proband and her sister had both harbored compound heterozygous variants of the VPS13B gene, namely c.10076_10077delCA (p.T3359fs*29) and c.6940+1G>T, which were respectively inherited from their mother and father. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were classified as pathogenic (PVS1+PS4+PM4+PP1; PVS1+PM2_Supporting+PM3+PP1). In vivo splicing assay confirmed that the c.6940+1G>T variant has produced a frameshift transcript with skipping of exon 38. Compared with the control group, the expression of RNA in the peripheral blood of the proband's parents has decreased to 65% ~ 70% (P < 0.01), whilst that in the proband and her sister has decreased to 40% (P < 0.001). Prenatal diagnosis at 12 weeks of gestation has found that the fetus only harbored the heterozygous c.10076_ 10077delCA variant. CONCLUSION The c.10076_10077delCA (p.T3359fs*29) frameshift variant and c.6940+1G>T splicing variant probably underlay the Cohen syndrome in this pedigree. Genetic testing has facilitated the diagnosis of this disease.
Female ; Humans ; East Asian People ; Intellectual Disability/genetics* ; Mutation ; Myopia/genetics* ; Pedigree ; Vesicular Transport Proteins/genetics* ; Child, Preschool ; Child

OBJECTIVE: To explore the genetic etiology of a child with Hypomagnesemia, epilepsy and mental retardation syndrome (HSMR). METHODS: A child who was admitted to the Children's Hospital of Shandong University on July 9, 2021 due to repeated convulsions for 2 months was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples of the child and his pedigree members were collected for the extraction of genomic DNA. Whole exome sequencing was carried out, and candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: The child, a 1-year-and-7-month-old male, had presented with epilepsy and global developmental delay. Serological testing revealed that he has low serum magnesium. Genetic testing showed that the child has harbored a heterozygous c.1448delT (p.Val483GlyfsTer29) variant of the CNNM2 gene, which was de novo in origin. The variant has caused substitution of the Valine at position 483 by Glycine and formation of a termination codon after 29 amino acids at downstream. As predicted by Swiss-Model online software, the variant may alter the protein structure, resulting in a truncation. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.1448delT (p.Val483GlyfsTer29) was predicted as a pathogenic variant (PVS1+PS2+PM2_Supporting+PP4). CONCLUSION The heterozygous c.1448delT variant of the CNNM2 gene probably underlay the HSMR in this child. Above finding has enriched the phenotype-genotype spectrum of the CNNM2 gene.
Humans ; Male ; Cation Transport Proteins ; Computational Biology ; Ethnicity ; Intellectual Disability/genetics* ; Magnesium ; Mutation ; Seizures/genetics* ; Infant