Association between placental DNA methylation and fetal congenital heart disease.

Congenital heart disease (CHD) is a worldwide problem with high morbidity and mortality. Early diagnosis of congenital heart disease is still a challenge in clinical work. In recent years, few studies indicated that placental methylation may be predictors of CHD. More studies are needed to confirm the association between placental methylation and CHD. The aim of this study was to investigate the association between prenatal placental DNA methylation and CHD. Placental tissues were obtained from four fetuses during the second trimester with isolated, non-syndromic congenital heart disease, including three cases with double outlet right ventricle (DORV) and one case with tetralogy of Fallot (TOF), and four unaffected fetuses as controls. The Illumina Infinium Human Methylation 850K BeadChip assay was employed to identify differential methylation sites (DMSs) and differential methylation regions (DMRs). Differential methylation was evaluated by comparing the ß-values for individual CpG loci in cases vs. controls. In addition, the function of genes was assessed through KEGG enrichment analysis, Gene Ontology (GO) analysis and KEGG pathway analysis. Compared with the control group, we identified 9625 differential methylation genes on 26,202 DMSs (p < 0.05), of which 6997 were hyper-methylation and 2628 were hypo-methylation. The top 30 terms of GO biological process and KEGG enrichment analysis of DMSs were connected with multiple important pathways of heart development and disease. Ten differentially methylated regions and the genes related to DMRs, such as TLL1, CRABP1, FDFT1, and PCK2, were identified. The deformity caused by the loss of function of these genes is remarkably consistent with the clinical phenotype of our cases. The DNA methylation level of placental tissue is closely associated with fetal congenital heart disease.

[Analysis of MYRF gene variant in a fetus with Cardiac-urogenital syndrome].

OBJECTIVE: To explore the genetic basis for a fetus with Cardiac-urogenital syndrome (CUGS). METHODS: A fetus with congenital heart disease identified at the Maternal Fetal Medical Center for Fetal Heart Disease, Beijing Anzhen Hospital Affiliated to Capital Medical University in January 2019 was selected as the study subject. Clinical data of the fetus was collected. Copy number variation sequencing (CNV-seq) and trio-whole exome sequencing (trio-WES) were carried out for the fetus and its parents. Candidate variants were verified by Sanger sequencing. RESULTS: Detailed fetal echocardiographic examination had revealed hypoplastic aortic arch. The results of trio-WES revealed that the fetus has harbored a de novo splice variant of the MYRF gene (c.1792-2A>C), for which both parents were of the wild-type. Sanger sequencing confirmed the variant to be de novo. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as likely pathogenic. CNV-seq has identified no chromosomal anomalies. And the fetus was diagnosed with Cardiac-urogenital syndrome. CONCLUSION: The de novo splice variant of the MYRF gene probably underlay the abnormal phenotype in the fetus. Above finding has enriched the spectrum of MYRF gene variants.

[Clinical and genetic characteristics of 12 cases of Loeys-Dietz syndrome].

OBJECTIVE: To summarize the clinical features and spectrum of genetic variants in 12 patients with Loeys-Dietz syndrome (LDS), and to explore the correlation between the type of genetic variants and clinical phenotypes. METHODS: Twelve patients suspected for LDS at Beijing Anzhen Hospital Affiliated to Capital Medical University from January 2015 to January 2022 were selected as the study subjects. Clinical data of the patients were collected. Genomic DNA was extracted from peripheral blood samples and subjected to genetic testing. Pathogenicity of candidate variants was analyzed. RESULTS: The clinical phenotypes of the 12 patients have mainly included cardiovascular, musculoskeletal, craniofacial, skin, ocular and other systemic signs. Four patients (patients 5-1, 5-2, 6, 7) have carried heterozygous missense variants of the TGFBR1 gene, 5 patients (patients 1-1, 1-2, 2, 3, 4) have carried heterozygous variants of the TGFBR2 gene, and 2 patients (patients 8-1, 8-2) had carried heterozygous frameshift variants of the TGFB3 gene. One patient (patient 9) had carried a heterozygous missense variant of the SMAD3 gene. Among these, TGFBR1 c.603T>G (p.1201M) and TGFB3 c.536delA (p.H179FS35) had not been reported previously. CONCLUSION: Variants of the TGFBR1, TGFBR2, SMAD3, TGFB2, TGFB3 and SMAD2 genes are mainly associated with LDS. The severity of the disease phenotype caused by the same variant may vary, whilst the clinical phenotype caused by different variant sites may be specific.

A novel intron mutation in FBN-1 gene identified in a pregnant woman with Marfan syndrome.

Marfan syndrome (MFS) is one of the most common hereditary connective tissue diseases, with great individual heterogeneity. We reported a Chinese pregnancy with Clinical diagnosis of MFS, performed whole-exome sequencing, and screened for the genetic abnormality. We also conducted an in vitro mini-gene splicing assay to demonstrate the predicted harmful effects of an intronic variant of FBN-1. Exome sequencing identified a novel intronic variant (c.6497-13 T>A) in intron 53 of the FBN-1 gene (NM_000138.4). It's predicted to insert 11 bp of intron 53 into the mature mRNA. The mini-gene splicing experiment demonstrated that c.6497-13 T>A could result in 11 bp retention in intron 53 to exon 54 (c.6496_6497ins gtttcttgcag) and the use of an alternative donor causing the frameshift p.Asp2166Glyfs*23. According to the results, the pregnant woman chose to continue the pregnancy and gave birth to a healthy baby. This study expands the genetic mutation spectrum of MFS patients and indicates the importance of intron sequencing.

Pressure-induced unexpected -2 oxidation states of bromine and superconductivity in magnesium bromide.

Finding novel compounds with unusual crystal structures and physical properties is always an important goal for the materials and chemistry community. Pressure becomes attractive due to its unique ability to break down many fundamental rules by modifying the chemical properties of elements, overcoming reaction barriers and shortening interatomic distances, leading to the formation of some novel materials with unexpected properties. In this work, for the first time we have analyzed the high-pressure phase diagram, crystal structures and electron properties of the Mg-Br system up to 200 GPa using unbiased structure searching techniques. Besides the already known MgBr2, here we report that three unusual stoichiometries of Mg-Br compounds can be stabilized at high pressures as MgBr3, MgBr and Mg4Br. Firstly, among the predicted stable compounds, we find that the Mg4Br in the I4/mmm structure stabilized at 178 GPa behaves as a typical electride, indicating that the formation pressure of an electride for Mg can be significantly reduced by bonding with Br atoms. Secondly, it is surprising that the unexpected oxidation states of Br approaching -2 are observed in the predicted I4/mmm Mg4Br and Pm3[combining macron]m MgBr compounds. Furthermore, P21/m MgBr3 and I4[combining macron]2m MgBr3 phases are predicted as superconductors with an estimated Tc of 23.2 and 0.49 K, respectively. Our work represents a significant step toward understanding the high pressure behaviors of alkaline earth halides and searching for novel high temperature superconductors.

Pressure-Induced Stable Binary Compounds of Magnesium and Germanium.

Motivated by the possibility to obtain unusual stoichiometric compounds (e.g., Na-Cl and Mg-O systems) with exotic properties at high pressures, we systematically investigated the high-pressure structures and chemical bonding of Mg-Ge systems by using a structure-searching method and first-principles calculations. Compared with the stable composition of Mg2 Ge at ambient pressure, several stoichiometries (e.g., Mg3 Ge, MgGe, and MgGe2 ) were predicted to be stable under high pressures. The Pm 3 ‾ m Mg3 Ge structure consists of a 12-fold-coordinated face-sharing GeMg12 cuboctahedron, whereas the P4/mmm MgGe and Cmcm MgGe2 phases form MgGe8 hexahedrons and MgGe4 polygons, respectively. All the stable phases of Mg-Ge compounds under high pressures exhibit metallic features owing to overlap between the conduction and valence bands. For Cmcm MgGe2 , the projected density of states near the Fermi energy mainly derive from Ge s, Ge p, and Ge d, which are responsible for its metallicity. The calculated superconducting critical temperature values of Cmcm Mg2 Ge and P4/mmm MgGe reach 10.3 and 9.07 K at 5 GPa, respectively.

The Structure and Properties of Magnesium-Phosphorus Compounds Under Pressure.

Inspired by the emergence of compounds with novel structures and unique properties (i.e., superconductivity and hardness) under high pressure, we systematically explored a binary Mg-P system under pressure, combining first-principles calculations with structure prediction. Several stoichiometries (Mg3 P, Mg2 P, MgP, MgP2 , and MgP3 ) were predicted to be stable under pressure. Especially, the P-P bonding patterns are different in the P-rich compounds and the Mg-rich compounds: in the former, the P-P bonding patterns form P2 , P3 , quadrilateral units, P-P⋅⋅⋅P chains or disordered "graphene-like" sublattice, while in the latter, the P-P bonding patterns eventually evolve isolated P ions. The analysis of integrated-crystal orbital Hamilton populations reveals that the P-P interactions are mainly responsible for the structural stability. The P-rich compounds with stoichiometries of MgP, MgP2 and MgP3 exhibit superconductive behaviors, and these phases show Tc in the range of 4.3-20 K. Our study provides useful information for understanding the Mg-P binary compounds at high pressure.

Generation of a TSC2 knockout embryonic stem cell line by CRISPR/Cas9 editing.

Tuberous Sclerosis Complex (TSC) is a severe developmental disorder with various clinical effects, primarily caused by TSC2 gene mutations, often involving loss of function(Henske,et al., 2016).To explore role of TSC2 in human heart development, we successfully developed a TSC2 knockout (TSC2-/-) human embryonic stem cells (hESCs) line using CRISPR/Cas9 gene editing. This TSC2-/- hESC line maintained a normal karyotype, expressed pluripotency markers strongly, and could differentiate into all three germ layers in vivo. This cell line will be a valuable tool for future research on the role of TSC2 in heart development.

Enhancement and Broadening of the Internal Electric Field of Hole-Transport-Layer-Free Perovskite Solar Cells by Quantum Dot Interface Modification.

Hole-transport-layer-free perovskite solar cells have attracted strong interest due to their simple structure and low cost, but charge recombination is serious. Built-in electric field engineering is an intrinsic driver to facilitate charge separation transport and improve the efficiency of photovoltaic devices. However, the enhancement of the built-in electric field strength is often accompanied by the narrowing of the space charge region, which becomes a key constraint to the performance improvement of the device. Here, we propose an effective regulation method, the component engineering of quantum dots, to enhance the strength of the built-in electric field and broaden the range of space charge. By using all inorganic CsPbBrxI3-x (x = 0, 1, 2, 3) quantum dot interface modification to passivate the defects of MAPbI3 perovskite films, the regulation law of quantum dot components on the work function of perovskite films was revealed, and the mechanism of their influence on the internal electric field intensity and space charge region distribution was further clarified, thereby fundamentally solving the serious problem of charge recombination. As directly observed by electron-beam-induced current (EBIC), the introduction of CsPbBr2I quantum dots can effectively enhance the interfacial electric field intensity, widening the space charge region from 160 to 430 nm. Moreover, the efficiency of the hole-free transport layer perovskite solar cells modified by CsPbBr2I quantum dots was also significantly enhanced by 1.5 times. This is an important guideline for electric field modulation and efficiency improvement within photovoltaic devices with other simplified structures.

Prognostic significance of IDH mutation in adult low-grade gliomas: a meta-analysis.

Mutations in the gene encoding isocitrate dehydrogenase (IDH) have been identified in approximately 65-90 % of low-grade gliomas (LGGs). Various studies examining the relationship between IDH mutation with the clinical outcome in patients with LGGs have yielded inconclusive results. The purpose of the present meta-analysis of literature is to determine this effect. We conducted a meta-analysis of 10 studies (937 patients) that evaluated the correlation between IDH mutation and overall survival (OS). For the quantitative aggregation of the survival results, the IDH mutation effect was measured by hazard ratio (HR). Overall, the pooled HR was 0.585 (95 % CI, 0.376-0.911, p = 0.025, random effect model) for patients with IDH mutation vs patients without IDH mutation. IDH mutation was associated with better overall survival of LGGs. At least this trend was observed in our analysis.

Genetic aetiology distribution of 398 foetuses with congenital heart disease in the prenatal setting.

AIMS: Copy number variant-sequencing (CNV-seq) and exome sequencing (ES) have been used as powerful tools in understanding the role of genetic variants in congenital heart diseases (CHDs). A few previous large cohort studies have utilized CNV-seq and ES to investigate prenatally diagnosed CHD. Here, we sought to determine the value of CNV-seq and ES for genetic evaluation of foetal CHDs. METHODS AND RESULTS: We recruited 398 pregnant women diagnosed with CHDs between 8 January 2017 and 30 November 2020. CNV-seq and ES were performed on foetal and parent samples. CHD cases were classified following the guidelines of the International Paediatric and Congenital Cardiac Code and the Tenth and Eleventh Revisions of the International Classification of Diseases. Data on aneuploids (AUP), pathogenic CNVs (pCNVs), and single nucleotide variants (SNVs) were collected and compared, following appropriate procedures. We identified genetic abnormalities in 129 (32.41%) foetuses. These abnormalities included AUP (10.80%), pCNVs (13.32%), and SNVs (8.04%). ES analysis yielded higher SNVs in cases without AUP or pCNVs. Non-isolated CHDs were associated with higher genetic abnormalities than isolated CHDs, mainly due to AUP differences between the two groups. The prevalence of genetic defects was the highest in foetuses with atrioventricular septal defects (AVSD), left ventricular outflow tract obstruction (LVOTO), and conotruncal defects (CTD). AVSD and anomalies of atrioventricular junctions and valves were associated with AUP abnormalities. CTD, anomalies of extrapericardial arterial trunks, and anomalies of the ventricular outflow tracts were the most common CHD categories diagnosed using CNVs. The most common CHDs associated with single ventricle (SV) abnormalities were heterotaxy (Hex) (14.89%), LVOTO (14.58%), and ventricular septal defect (VSD) (26.67%, 4/15). Although the ES yields were higher than CNV-seq for VSD (44.4%, 4/9), LVOTO (20%, 7/35), Hex (14.89%, 7/47), and CTD (9.1%, 11/121), its diagnostic yield did not increase for SV (6.7%, 1/15), AVSD (3.8%, 1/26), or right ventricular obstruction defects (2.6%, 1/38). The most common mutations were observed in KMT2D, CHD7, and NOTCH1. CONCLUSIONS: To our knowledge, this is the largest cohort study to investigate the incidence of SNVs using ES in foetal CHD. CNV-seq and ES identified genetic abnormalities in nearly 1/3 of foetal CHD cases. Thus, CNV-seq and ES can provide clinically relevant information for pregnancy management.

Diverse cardiac phenotypes among different carriers of the same MYH7 splicing variant allele (c.732+1G>A) from a family.

BACKGROUND: Left ventricular non-compaction cardiomyopathy (LVNC) is a rare congenital heart defect. Gene defections have been found in patients with LVNC and their family members; and MYH7 is the most frequent gene associated with LVNC. METHODS: We performed a complete prenatal ultrasound and echocardiographic examination on a fetus with cardiac abnormality and a parent-child trio whole-exome sequencing to identify the potential genetic causes. When the genetic abnormality in MYH7 was identified in the fetus, we performed echocardiography and genetic screening on its high-risk relatives. RESULTS: Second trimester ultrasound and echocardiography showed several malformations in the fetus: Ebstein's anomaly (EA), heart dilatation, perimembranous ventricle septal defects, mild seroperitoneum, and single umbilical artery. Heterozygous genotyping of a splicing variant allele (NM_00025.3: c.732+G>A) was identified in this fetus and her mother, not her father, indicating a maternal inheritance. Subsequently, direct sequencing confirmed the presence of this splicing variant among her grandmother (mother of mother), mother, older sister, and herself in a heterozygous manner. No PCR products were amplified by qRT-PCR for the RNA samples extracted from peripheral blood cells. In addition to this proband who was diagnosed with EA, her older sister and grandmother (mother of mother) were diagnosed with isolated asymptomatic LVCN, but her mother was just a carrier with no marked clinical manifestations after family screening. CONCLUSION: The presence of MYH7 splicing variant c.732+G>A can be inherited maternally, and its cardiac phenotypes are different from one carrier to another.

Expanding the phenotype associated with SMARCC2 variants: a fetus with tetralogy of Fallot.

BACKGROUND: Coffin-Siris syndrome-8 (CSS8) is a rare autosomal dominant disorder caused by variants in SMARCC2, a core subunit of the chromatin-remodeling complex BRG1-associated factor (BAF). The clinical characteristics of this disorder have not been entirely determined because of the rarity of clinical reports. The BAF complex plays a crucial role in embryogenesis and cardiac development, and pathogenic variants in genes encoding the components of the BAF complex have been associated with congenital heart disease (CHD). However, variants in SMARCC2 have not been reported in patients with CHD. CASE PRESENTATION: A 28-year-old primigravida was referred at 24 weeks gestation for prenatal echocardiography. The echocardiographic findings were consistent with a prenatal ultrasound diagnosis of tetralogy of Fallot (TOF). After detailed counseling, the couple decided to terminate the pregnancy and undergo genetic testing. A trio (fetus and the parents) whole-exome sequencing (WES) and copy number variation sequencing (CNV-seq) were performed. CNV-seq identified no chromosomal abnormalities. WES analysis revealed a pathogenic, de novo heterozygous frameshift variant in SMARCC2 (NM_003075.5: c.3561del, p.Leu1188fs). The genetic diagnosis of CSS8 was considered given the identification of the SMARCC2 pathogenic variant. CONCLUSIONS: We report the first prenatal case with the SMARCC2 variant. The presence of CHD further broadens the phenotypic spectrum of SMARCC2-related disease.

Placental DNA Methylation Abnormalities in Prenatal Conotruncal Heart Defects.

Objective: This study aims to characterize the abnormal changes in placental DNA methylation associated with conotruncal heart defects (CTDs) and the level of methylation as epigenetic biomarkers for CTDs detection. Methods: This was a prospective study involving 28 fetuses diagnosed with CTDs in the second trimester at Beijing Anzhen Hospital between September 2020 and June 2021. These cases were classified into four groups based on their subtypes. 12 normal fetuses were used as controls. Placental tissue was obtained after inducing labor in fetuses. To identify differential methylation sites (DMSs) and regions (DMRs) in cases vs. controls, an Infinium Human Methylation 850 k bead chip was used. Differential methylation was assessed by comparing the ß-values for individual CpG loci. Based on the p-value (<0.05), the most discriminating CpG sites were identified. The area under the receiver-operating-characteristics curve (AUC) was used to determine the predictive accuracy of CpG loci with significant methylation changes for CTDs. The function of genes was assessed through KEGG enrichment analysis, Gene Ontology (GO) analysis, and KEGG pathway analysis. Results: In comparison to the control group, the DNA methylation of the placental tissue is significantly different in fetuses with CTDs. We identified the most significantly different methylated loci and they demonstrated excellent individual predictive accuracy for CTDs detection with AUC >0.9 in cases compared with controls. HOXD9, CNN1, NOTCH1, and ECE1 were identified as CTDs-detection candidate genes. Conclusion Our study established the abnormal changes in placental methylation associated with CTDs and potential epigenetic biomarkers for CTDs detection.

Case Report: Biventricular Noncompaction Cardiomyopathy With Pulmonary Stenosis and Bradycardia in a Fetus With KCNH2 Mutation.

Background: Left ventricular noncompaction (LVNC) is a rare cardiomyopathy, long QT syndrome (LQTS) is a rare ion channel disease, and simultaneous occurrence of both is even rarer. Further clinical reports and studies are needed to identify the association between LVNC and LQTS and the underlying mechanism. Methods and Results: A 26-year-old primigravida was referred at 25 weeks gestation for prenatal echocardiography due to fetal bradycardia detected during the routine ultrasound examination. The echocardiographic findings were consistent with biventricular noncompaction cardiomyopathy (BVNC) with pulmonary stenosis and suspected LQTS. After detailed counseling, the couple decided to terminate the pregnancy, and subsequent postmortem examination confirmed BVNC and pulmonary stenosis. Then, A trio (fetus and the parents) whole-exome sequencing (WES) and copy number variation sequencing (CNV-seq) were performed. CNV-seq identified no aneuploidy or pathogenic CNV. A de novo missense variant in KCNH2 (NM_000238.3:c.1847A > G,p.Tyr616Cys) was identified by WES. This KCNH2 missense mutation was classified as pathogenic according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology variant interpretation guidelines. Conclusion: We report the first prenatal case of KCNH2 mutation presenting with LVNC combined with bradycardia and second-degree 2:1 atrioventricular block. Importantly, this case reminds clinicians to systematically search ion channel gene mutations in patients with LVNC and arrhythmia.

Genetic and Clinical Features of Heterotaxy in a Prenatal Cohort.

Objectives: Some genetic causes of heterotaxy have been identified in a small number of heterotaxy familial cases or animal models. However, knowledge on the genetic causes of heterotaxy in the fetal population remains scarce. Here, we aimed to investigate the clinical characteristics and genetic spectrum of a fetal cohort with heterotaxy. Methods: We retrospectively investigated all fetuses with a prenatal diagnosis of heterotaxy at a single center between October 2015 and November 2020. These cases were studied using the genetic testing data acquired from a combination of copy number variation sequencing (CNV-seq) and whole-exome sequencing (WES), and their clinical phenotypes were also reviewed. Result: A total of 72 fetuses diagnosed with heterotaxy and complete clinical and genetic results were enrolled in our research. Of the 72 fetuses, 18 (25%) and 54 (75%) had left and right isomerism, respectively. Consistent with the results of a previous study, intracardiac anomalies were more severe in patients with right atrial isomerism than in those with left atrial isomerism (LAI) and mainly manifested as atrial situs inversus, bilateral right atrial appendages, abnormal pulmonary venous connection, single ventricles or single atria, and pulmonary stenosis or atresia. In 18 fetuses diagnosed with LAI, the main intracardiac anomalies were bilateral left atrial appendages. Of the 72 fetuses that underwent CNV-seq and WES, 11 (15.3%) had positive genetic results, eight had definitive pathogenic variants, and three had likely pathogenic variants. The diagnostic genetic variant rate identified using WES was 11.1% (8/72), in which primary ciliary dyskinesia (PCD)-associated gene mutations (CCDC40, CCDC114, DNAH5, DNAH11, and ARMC4) accounted for the vast majority (n = 5). Other diagnostic genetic variants, such as KMT2D and FOXC1, have been rarely reported in heterotaxy cases, although they have been verified to play roles in congenital heart disease. Conclusion: Thus, diagnostic genetic variants contributed to a substantial fraction in the etiology of fetal heterotaxy. PCD mutations accounted for approximately 6.9% of heterotaxy cases in our fetal cohort. WES was identified as an effective tool to detect genetic causes prenatally in heterotaxy patients.

Genetic abnormalities in fetal congenital heart disease with aberrant right subclavian artery.

Fetal aberrant right subclavian artery (ARSA) is a relatively common sonographic finding. Congenital heart disease (CHD) is the most common structural abnormality in patients with ARSA. We aimed to assess the prevalence of genetic abnormalities, particularly sequence variants, in fetuses with CHD and ARSA. By clinical phenotyping and genomic sequencing, we retrospectively reviewed all fetuses with a prenatal diagnosis of CHD combined with ARSA at a single center. As a result, we identified 30 fetuses with ARSA combined with CHD, with conotruncal anomalies being the most common (n = 12, 40%), followed by left ventricular outflow tract obstruction (n = 6, 20%) and atrioventricular septal defects (n = 6, 20%). Overall, 18 (60%) cases had a genetic diagnosis. Copy number variation sequencing analysis identified six (20%) fetuses with aneuploidy and seven (23%) with pathogenic copy-number variants. Whole-exome sequencing (WES) analysis of the remaining 17 cases revealed diagnostic genetic variants in five (29%) cases, indicating that the diagnostic yield of WES for the entire cohort was 17% (5/30). Our findings reveal the high burden of genetic abnormalities in fetal CHD with ARSA. Single-gene disorders contribute substantially to the genetic etiology of fetal CHD with ARSA.

Detection of TSC1/TSC2 mosaic variants in patients with cardiac rhabdomyoma and tuberous sclerosis complex by hybrid-capture next-generation sequencing.

BACKGROUND: Fetal cardiac rhabdomyoma (CR) is strongly associated with tuberous sclerosis complex (TSC), which is caused by variants in TSC1 and TSC2. However, in 10%-15% of patients with clinically confirmed TSC, no TSC1/TSC2 variants are identified by panel sequencing or multiplex ligation-dependent probe amplification (MLPA). METHODS: We analyzed eight fetuses with CR and their families. No TSC1/TSC2 variants had previously been identified for six of these fetuses, and we suspected the other two families of gonadal mosaicism. We performed next-generation sequencing (NGS) using CR tissue, umbilical cord tissue, and parental blood. All positive results, involving two paternal semen, were verified by droplet digital polymerase chain reaction (ddPCR). RESULTS: Four fetuses carried low-level mosaic variants (0.05%-14.89%), and two only exhibited somatic mosaic variants in the CR tissue (15.76% and 37.69%). Two fathers had gonadal mosaicism (9.07% and 4.86%). We identified nine pathogenic variants in eight fetuses, including one fetus with a second-hit variant. CONCLUSION: The fetuses assessed in this study carried low-level and somatic mosaic variants, and CR tissue from one fetus exhibited a second-hit variant. Heterozygous gonadal variants can exist in patients with low-level mosaicism. Combining NGS with ddPCR improves the accuracy of prenatal TSC diagnosis.

Generation of a NONO homozygous knockout human induced pluripotent stem cell line by CRISPR/Cas9 editing.

The non-POU domain containing octamer-binding gene (NONO) encodes a member of a small family of RNA-binding and DNA-binding proteins, whose variants can cause intellectual disability and congenital heart defects. In this study, we generated a homozygous NONO knockout (NONO-KO) induced pluripotent stem cell (iPSC) line (CMUi002-A-1) using the CRISPR/Cas9-based genome editing system. The gene-edited line had a normal karyotype, expressed pluripotency markers, and was able to differentiate into all three germ layers in vivo. This cell line will provide a platform to study the pathogenic mechanisms of noncompaction cardiomyopathy and neurocyte dysfunction related to NONO mutations.