Phenotype and genotype of 87 patients with Mowat-Wilson syndrome and recommendations for care

Neuropathologic Findings in Mowat-Wilson Syndrome at Autopsy, Including a Suprasellar Spindle Cell Lipoma

Mowat-Wilson Syndrome is an autosomal dominant disorder caused by de novo heterozygous mutations of ZEB2 on 2q22. It is characterized by developmental delay, Hirschsprung's disease, seizures, and a wide variety of malformations affecting the neurologic, cardiac, and genitourinary systems. Reports describing the findings of Mowat-Wilson Syndrome at autopsy are sparse. Case reports of suprasellar spindle cell lipomas are even rarer, a circumstance that contributes to uncertainty regarding their etiology as true neoplasms rather than congenital malformations. Here we report the gross, histopathologic, and molecular findings of a 4-year-old female with Mowat-Wilson Syndrome presenting with sepsis in the setting of otitis media and incidentally found to have a rare suprasellar spindle cell lipoma demonstrating loss of RB1 by immunohistochemistry, suggestive of a neoplastic etiology.

Proband-Only Exome Sequencing for Intellectual Disability in Iran: Diagnostic Yield and Genetic Insights

Intellectual disability (ID) is a leading cause for referral to genetic services, with the most severe cases typically attributed to single genetic defects. This study aimed to evaluate the diagnostic yield of cost-effective proband-only exome sequencing for individuals diagnosed with ID within the Iranian population for the first time where a high rate of parental consanguinity exists. A total of 99 unrelated patients with ID were investigated by exome sequencing during 8 years. As a result, 43 pathogenic/likely pathogenic variants were identified in 40 patients, indicating a molecular diagnostic rate of 40.4% (40/99). The inclusion of five chromosomal copy number variations in the subsequent analysis increased the diagnostic rate of proband-only exome sequencing to 45.4% (45/99). Additionally, parental testing revealed five de novo variants. This contributed to a total diagnostic rate of 50.5% (50/99). In our study, proband-only exome sequencing achieved a remarkable diagnostic rate, identifying nearly half of the ID cases. This rate of diagnosis could be primarily attributed to prevalent consanguineous marriage in the Iranian population and the rare identification of de novo variants. With the ongoing advancements in neurogenetics, proband-only exome sequencing demonstrates significant potential as a future cost-effective diagnostic approach in Iran.

Expanding the Genetic and Phenotypic Spectrum of Mowat-Wilson Syndrome: A Study of 10 Turkish Patients With an Intrafamilial Recurrence Caused by First Intragenic Large Deletion

Mowat-Wilson syndrome (MWS) is a complex disorder caused by heterozygous ZEB2 gene variations creating haploinsufficiency. The main clinical features are evolving facial dysmorphism, intellectual disability, eye and brain malformations, and various organ anomalies. Our study examines 10 Turkish patients, who had clinical diagnosis, underwent evaluation, clinical investigations, and genetic tests in multiple tertiary centers across Türkiye, and were molecularly diagnosed with MWS. Molecular analysis with sequencing techniques alongside array testing unveiled disease-causing variations in addition to novel variants, including two siblings with recurrent multiexon deletion. Clinical presentations varied, featuring neurodevelopmental delay and characteristic facial traits and organ malformations across all cases, alongside less frequently reported manifestations such as laryngomalacia or rocker bottom feet in addition to new features such as macroorchidism and osteoporosis. Our findings expand the genetic and phenotypical spectrum of MWS, and hint at potential implications of gonadal mosaicism. While establishing clear genotype-phenotype correlations poses challenges, comprehensive genetic testing remains pivotal for precise diagnosis and management. The study highlights the complexity of MWS genetics, with potential implications of gonadal mosaicism on recurrence. Further research is needed to elucidate mechanisms driving phenotypic variability, potential hotspots, and mechanisms for recurrent variations. We report on the largest cohort with MWS from Türkiye.

ZEB2 signaling is essential for ureteral smooth muscle cell differentiation and maintenance

Mowat-Wilson Syndrome (MWS) is a multiple congenital anomaly syndrome caused by mutations in the ZEB2, which plays a critical role in cell fate determination and differentiation during development. Congenital anomalies of the kidney and urinary tract (CAKUT) have been reported in MWS patients. However, the role of ZEB2 in urinary tract development and the cellular and molecular mechanism underlining the CAKUT phenotypes in MWS remains unknown. We performed ZEB2 protein expression analysis in the developing mouse ureter. We generated Zeb2 ureteral mesenchyme-specific conditional knockout mice by crossing Zeb2 floxed mice with Tbx18Cre mice (Zeb2 cKO) and analyzed the urinary tract phenotypes in Zeb2 cKO mice and wild-type littermate controls by gross and histological examination. Ureteral cellular and molecular phenotypes were studied using TAGLN, ACTA2, FOXD1, POSTN, CDH1, TBX18, and SOX9 ureteral cell-specific markers. We found that ZEB2 is expressed in TBX18+ ureteral mesenchymal cells during mouse ureter development. Deletion of Zeb2 in developing ureteral mesenchymal cells causes hydroureter and hydronephrosis phenotypes, leading to obstructive uropathy, kidney failure, and early mortality. Cellular and molecular marker analyses showed that the TAGLN+ACTA2+ ureteral smooth muscle cells (SMCs) layer is not formed in Zeb2 cKO mice at E15.5, but the FOXD1+ and POSTN+ tunica adventitia cells layer is significantly expanded compared to wild-type controls. CDH1+ urothelium cells are reduced considerably in the Zeb2 cKO ureters at E15.5. Mechanistically, we found that Zeb2 cKO mice have significantly decreased TBX18 expression but an increased SOX9 expression in the developing ureter at E14.5 and E15.5 compared to wild-type littermate controls. Our results show that ZEB2 is essential for ureter development by maintaining ureteral mesenchymal cell differentiation into normal ureteral SMCs. Our study also shed new light on the pathological mechanism underlying the developmental abnormalities of the urinary tract phenotypes in MWS patients.

CDK13-Related Disorder: Novel Insights From A Series of 27 Cases and Recommendations for Clinical Management

In 2016, Sifrim and colleagues described the first group of patients carrying heterozygous pathogenic variants in CDK13 and sharing major clinical features mainly consisting of congenital heart defects, intellectual disability and peculiar facial features (Congenital Heart Defects, Dysmorphic Facial Features, and Intellectual Developmental Disorder; CHDFIDD, OMIM # 617360). This condition is generally referred to as CDK13-related disorder, and since then other reports have provided further clinical and molecular information. Here we describe a group of 27 previously unreported patients to more accurately profile the clinical spectrum associated with CDK13 variants, disclosing novel associated findings, such as complex craniosynostosis and variable skeletal features (e.g., cranio-cervical anomalies). We also focused on the ocular phenotype that appears to include bilateral congenital glaucoma, posterior embriotoxon, buphthalmos and Duane anomaly. Finally, we observed two cases of mother-to-daughter transmission. Our work clarifies some novel features of CHDFIDD, defines the differential diagnosis of this disorder, and provides recommendations for its clinical management.

Peter C, Lovell S, Rafi SK, Butler MG. ZEB2 Gene Pathogenic Variants Across Protein-Coding Regions and Impact on Clinical Manifestations: A Review

Mowat-Wilson syndrome (MWS) is a rare multi-system genetic disorder caused by variants in the Zinc Finger E-Box-Binding Homeobox 2 (ZEB2) gene. ZEB2 is an autosomal dominant gene containing ten exons within the canonical version transcript (Isoform: O60315-1). The ZEB2 gene encodes six functional domains and seven non-domain regions. This review provides a comprehensive summary of pathogenic variants and their associated MWS clinical characteristics, focusing on ZEB2 pathogenic variants, functional protein domains and non-domain regions with clinical features. A systematic literature search from 2001 to 2023 and of unpublished datasets found 191 individuals with reported clinical features and genotypic data. Genetic defects and clinical manifestations were examined that presumably impact on the structure and function of the ZEB2 gene, thereby causing multiple developmental defects with corresponding clinical presentation. This study found more nonsense ZEB2 variants observed within exon 8, which encodes four of the six protein domains: the CtBP-interacting domain (CID), homeodomain (HD), SMAD-binding domain (SMD or SBD) and part of the N-terminal zinc finger cluster (N-ZF), suggesting exon 8 plays a crucial role in this protein structure and function with multi-organ involvement. Exon 8 defects were found to be statistically more represented for gastrointestinal findings when compared to other exons, while frameshift defects were more often seen for the typical MWS face in non-domain protein regions. In contrast, nonsense or other types of variants in exons 3, 4 and 5 which encode only flanking non-domain regions were observed more often, compared with other exons excluding exon 8, to be specifically involved in the MWS facial gestalt, brain malformations, developmental delay and intellectual disability. Deleterious ZEB2 frameshift (45%) and nonsense (38%) gene variants were most often observed with deletions at 6% and missense at 5%. The genotype and clinical relationships in MWS can provide insights into prognosis, morbidity, clinical surveillance strategies and counseling of family members.

Temporal Regulation of Myopia and Inflammation-Associated Pathways in the Interphotoreceptor Retinoid-Binding Protein Knockout Mouse Model

PURPOSE

Myopia is a complex disorder with etiology involving an interplay between several genetic and environmental factors. Interphotoreceptor retinoid-binding protein (IRBP) is found in the subretinal space and is crucial in the visual cycle. The interphotoreceptor retinoid-binding protein knockout mouse (IRBP KO) was established as a model system to understand myopia and retinal degeneration. The current study investigated genes associated with myopia, retinal homeostasis, and inflammation in IRBP KO.

METHODS

RNA from retinas of congenic IRBP KO and wild-type C57BL/6J (WT) mice at postnatal day 5 (P5), P40, and P213 were subjected to digital droplet PCR (ddPCR) using a Bio-Rad automated droplet generator and QX200 reader. Target genes were selected based on genome-wide association studies, animal models, myopia studies, and other genes associated with retinal homeostasis and inflammation. HPRT, a housekeeping gene, was used for normalization. An average expression ratio (target/HPRT) and standard deviation (SD) were calculated. ANOVA assessed statistical significance, and a p < 0.05 was considered significant.

RESULTS

The ddPCR data analysis indicated that numerous myopia and inflammation-associated genes were differentially regulated in IRBP KO retinas with distinct temporal variation (upregulated at P5, decreased at P40, and no change at P213 relative to WT). C1qa, Gjd2, Sntb1, and Vsx2 emerged as top genetic candidate pathways. Compared with WT, immunoblotting analysis of C1qa showed no significant differences at P5 but significantly increased protein levels at P7 in IRBP KOs. Vsx2 remained unaltered at P5 and P7 in KO when compared with WT.

CONCLUSIONS

Data analysis indicated significant contributions from C1q, Gjd2, Sntb1, and Vsx2 genes in IRBP deficiency.

Genetic Insights into Congenital Cardiac Septal Defects-A Narrative Review

Congenital heart diseases (CHDs) are a group of complex diseases characterized by structural and functional malformations during development in the human heart; they represent an important problem for public health worldwide. Within these malformations, septal defects such as ventricular (VSD) and atrial septal defects (ASD) are the most common forms of CHDs. Studies have reported that CHDs are the result of genetic and environmental factors. Here, we review and summarize the role of genetics involved in cardiogenesis and congenital cardiac septal defects. Moreover, treatment regarding these congenital cardiac septal defects is also addressed.

Overexpression of BDNF Suppresses the Epileptiform Activity in Cortical Neurons of Heterozygous Mice with a Transcription Factor Sip1 Deletion

Since genetic mutations during brain development play a significant role in the genesis of epilepsy, and such genetically determined epilepsies are the most difficult to treat, there is a need to study the mechanisms of epilepsy development with deletions of various transcription factors. We utilized heterozygous mice (Sip1wt/fl) with a neuronal deletion of the transcription factor Sip1 (Smad interacting protein 1) in the cerebral cortex. These mice are characterized by cognitive impairment and are prone to epilepsy. It is known that the brain-derived neurotrophic factor (BDNF) has a neuroprotective effect in various neurodegenerative diseases. Therefore, we created and applied an adeno-associated construct carrying the BDNF sequence selectively in neurons. Using in vitro and in vivo research models, we were able to identify a key gen, the disruption of whose expression accompanies the deletion of Sip1 and contributes to hyperexcitation of neurons in the cerebral cortex. Overexpression of BDNF in cortical neurons eliminated epileptiform activity in neurons obtained from heterozygous Sip1 mice in a magnesium-free model of epileptiform activity (in vitro). Using PCR analysis, it was possible to identify correlations in the expression profile of genes encoding key proteins responsible for neurotransmission and neuronal survival. The effects of BDNF overexpression on the expression profiles of these genes were also revealed. Using BDNF overexpression in cortical neurons of heterozygous Sip1 mice, it was possible to achieve 100% survival in the pilocarpine model of epilepsy. At the level of gene expression in the cerebral cortex, patterns were established that may be involved in the protection of brain cells from epileptic seizures and the restoration of cognitive functions in mice with Sip1 deletion.

Identification of the DNA methylation signature of Mowat-Wilson syndrome

Mowat-Wilson syndrome (MOWS) is a rare congenital disease caused by haploinsufficiency of ZEB2, encoding a transcription factor required for neurodevelopment. MOWS is characterized by intellectual disability, epilepsy, typical facial phenotype and other anomalies, such as short stature, Hirschsprung disease, brain and heart defects. Despite some recognizable features, MOWS rarity and phenotypic variability may complicate its diagnosis, particularly in the neonatal period. In order to define a novel diagnostic biomarker for MOWS, we determined the genome-wide DNA methylation profile of DNA samples from 29 individuals with confirmed clinical and molecular diagnosis. Through multidimensional scaling and hierarchical clustering analysis, we identified and validated a DNA methylation signature involving 296 differentially methylated probes as part of the broader MOWS DNA methylation profile. The prevalence of hypomethylated CpG sites agrees with the main role of ZEB2 as a transcriptional repressor, while differential methylation within the ZEB2 locus supports the previously proposed autoregulation ability. Correlation studies compared the MOWS cohort with 56 previously described DNA methylation profiles of other neurodevelopmental disorders, further validating the specificity of this biomarker. In conclusion, MOWS DNA methylation signature is highly sensitive and reproducible, providing a useful tool to facilitate diagnosis.

Clinical and Genetic Correlation in Neurocristopathies: Bridging a Precision Medicine Gap

Neurocristopathies (NCPs) encompass a spectrum of disorders arising from issues during the formation and migration of neural crest cells (NCCs). NCCs undergo epithelial-mesenchymal transition (EMT) and upon key developmental gene deregulation, fetuses and neonates are prone to exhibit diverse manifestations depending on the affected area. These conditions are generally rare and often have a genetic basis, with many following Mendelian inheritance patterns, thus making them perfect candidates for precision medicine. Examples include cranial NCPs, like Goldenhar syndrome and Axenfeld-Rieger syndrome; cardiac-vagal NCPs, such as DiGeorge syndrome; truncal NCPs, like congenital central hypoventilation syndrome and Waardenburg syndrome; and enteric NCPs, such as Hirschsprung disease. Additionally, NCCs' migratory and differentiating nature makes their derivatives prone to tumors, with various cancer types categorized based on their NCC origin. Representative examples include schwannomas and pheochromocytomas. This review summarizes current knowledge of diseases arising from defects in NCCs' specification and highlights the potential of precision medicine to remedy a clinical phenotype by targeting the genotype, particularly important given that those affected are primarily infants and young children.

Mowat-Wilson syndrome: unraveling the complexities of diagnosis, treatment, and symptom management

Mowat-Wilson syndrome can be mentioned as one of the most severe and, at the same time, rare genetic abnormalities. The inheritance pattern of this disorder is an autosomal dominant pattern. In this disease, the ZEB2 gene becomes abnormal. The severity of the disease and associated signs and symptoms can vary widely but may include distinct facial features, developmental delay, intellectual disability, and Hirschsprung. MWS treatment may vary based on the specific symptoms that appear in each individual. This review will examine the gene involved in this disease, phenotype, clinical manifestations, ways of diagnosis, and treatment of this disease.

Mowat-Wilson Syndrome: Case Report and Review of ZEB2 Gene Variant Types, Protein Defects and Molecular Interactions

Mowat-Wilson syndrome (MWS) is a rare genetic neurodevelopmental congenital disorder associated with various defects of the zinc finger E-box binding homeobox 2 (ZEB2) gene. The ZEB2 gene is autosomal dominant and encodes six protein domains including the SMAD-binding protein, which functions as a transcriptional corepressor involved in the conversion of neuroepithelial cells in early brain development and as a mediator of trophoblast differentiation. This review summarizes reported ZEB2 gene variants, their types, and frequencies among the 10 exons of ZEB2. Additionally, we summarized their corresponding encoded protein defects including the most common variant, c.2083 C>T in exon 8, which directly impacts the homeodomain (HD) protein domain. This single defect was found in 11% of the 298 reported patients with MWS. This review demonstrates that exon 8 encodes at least three of the six protein domains and accounts for 66% (198/298) of the variants identified. More than 90% of the defects were due to nonsense or frameshift changes. We show examples of protein modeling changes that occurred as a result of ZEB2 gene defects. We also report a novel pathogenic variant in exon 8 in a 5-year-old female proband with MWS. This review further explores other genes predicted to be interacting with the ZEB2 gene and their predicted gene-gene molecular interactions with protein binding effects on embryonic multi-system development such as craniofacial, spine, brain, kidney, cardiovascular, and hematopoiesis.

Unilateral progressive anterior iris adhesions in Mowat-Wilson syndrome: a new ocular finding

Ocular associations in Mowat-Wilson syndrome (MWS) are rare. Those involving the anterior segment are scarce in the literature. We describe a child with genetic confirmation of MWS that presented with acquired onset of unilateral anterior iris adhesions with no known trauma.

Human Genetics of Atrial Septal Defect

Although atrial septal defects (ASD) can be subdivided based on their anatomical location, an essential aspect of human genetics and genetic counseling is distinguishing between isolated and familiar cases without extracardiac features and syndromic cases with the co-occurrence of extracardiac abnormalities, such as developmental delay. Isolated or familial cases tend to show genetic alterations in genes related to important cardiac transcription factors and genes encoding for sarcomeric proteins. By contrast, the spectrum of genes with genetic alterations observed in syndromic cases is diverse. Currently, it points to different pathways and gene networks relevant to the dysregulation of cardiomyogenesis and ASD pathogenesis. Therefore, this chapter reflects the current knowledge and highlights stable associations observed in human genetics studies. It gives an overview of the different types of genetic alterations in these subtypes, including common associations based on genome-wide association studies (GWAS), and it highlights the most frequently observed syndromes associated with ASD pathogenesis.

Novel STAMBP mutations in a Chinese girl with rare symptoms of microcephaly-capillary malformation syndrome and Mowat-Wilson syndrome

Microcephaly-capillary malformation syndrome (MIC-CAP) and Mowat-Wilson syndrome (MWS) are both rare hereditary diseases with several overlapping symptoms. We here report a Chinese patient simultaneously affected by MIC-CAP and MWS, presenting with moderate anaemia because of repeated, unilateral refractory epistaxis. The girl was initially diagnosed with MWS after discovery of a pathogenic nonsense mutation in ZEB2. Starting from the age of 3 years old, the child experienced repeated epistaxis on the right side without obvious incentive or trauma. The bleeding was quite difficult to stop and her hemoglobin dropped from 124 g/L to 64 g/L in three months. Both coagulation disorders and allergic rhinitis were excluded by extensive workup and experimental therapeutics. Retrospective genetic analysis revealed that she carried two novel compound heterozygous mutations in STAMBP (c.610T > C: p.Ser204Pro and c.945C > G: p.Asn315Lys). This case report demonstrates a rare presentation of MIC-CAP in the pediatric population and enriches the variant spectrum of STAMBP.

Epilepsy is an important feature of KBG syndrome associated with poorer developmental outcome

OBJECTIVE

The aim of this study was to describe the epilepsy phenotype in a large international cohort of patients with KBG syndrome and to study a possible genotype-phenotype correlation.

METHODS

We collected data on patients with ANKRD11 variants by contacting University Medical Centers in the Netherlands, an international network of collaborating clinicians, and study groups who previously published about KBG syndrome. All patients with a likely pathogenic or pathogenic ANKRD11 variant were included in our patient cohort and categorized into an "epilepsy group" or "non-epilepsy group". Additionally, we included previously reported patients with (likely) pathogenic ANKRD11 variants and epilepsy from the literature.

RESULTS

We included 75 patients with KBG syndrome of whom 26 had epilepsy. Those with epilepsy more often had moderate to severe intellectual disability (42.3% vs 9.1%, RR 4.6 [95% CI 1.7-13.1]). Seizure onset in patients with KBG syndrome occurred at a median age of 4 years (range 12 months - 20 years), and the majority had generalized onset seizures (57.7%) with tonic-clonic seizures being most common (23.1%). The epilepsy type was mostly classified as generalized (42.9%) or combined generalized and focal (42.9%), not fulfilling the criteria of an electroclinical syndrome diagnosis. Half of the epilepsy patients (50.0%) were seizure free on anti-seizure medication (ASM) for at least 1 year at the time of last assessment, but 26.9% of patients had drug-resistant epilepsy (failure of ≥2 ASM). No genotype-phenotype correlation could be identified for the presence of epilepsy or epilepsy characteristics.

SIGNIFICANCE

Epilepsy in KBG syndrome most often presents as a generalized or combined focal and generalized type. No distinctive epilepsy syndrome could be identified. Patients with KBG syndrome and epilepsy had a significantly poorer neurodevelopmental outcome compared with those without epilepsy. Clinicians should consider KBG syndrome as a causal etiology of epilepsy and be aware of the poorer neurodevelopmental outcome in individuals with epilepsy.

Mowat-Wilson syndrome factor ZEB2 controls early formation of human neural crest through BMP signaling modulation

Mowat-Wilson syndrome is caused by mutations in ZEB2, with patients exhibiting characteristics indicative of neural crest (NC) defects. We examined the contribution of ZEB2 to human NC formation using a model based on human embryonic stem cells. We found ZEB2 to be one of the earliest factors expressed in prospective human NC, and knockdown revealed a role for ZEB2 in establishing the NC state while repressing pre-placodal and non-neural ectoderm genes. Examination of ZEB2 N-terminal mutant NC cells demonstrates its requirement for the repression of enhancers in the NC gene network and proper NC cell terminal differentiation into osteoblasts and peripheral neurons and neuroglia. This ZEB2 mutation causes early misexpression of BMP signaling ligands, which can be rescued by the attenuation of BMP. Our findings suggest that ZEB2 regulates early human NC specification by modulating proper BMP signaling and further elaborate the molecular defects underlying Mowat-Wilson syndrome.

"Liu-Liang-Chung" syndrome with multiple congenital anomalies and the distinctive craniofacial features caused by dominant ZEB2 gene gain mutation

BACKGROUND

Contiguous gene gain syndrome including entire ZEB2 may be a novel syndrome. In the past, there were no easily distinct and recognizable features as a guide for precise clinical and genetic diagnosis of the syndrome.

CASE PRESENTATION

We report a novel case with the syndrome with a novel de novo 22.16 Mb duplication at 2q21.2-q24.1. The syndrome is characterized by multiple anomalies including the same typical craniofacial phenotype that is entirely different from Mowat-Wilson syndrome (MWS), and other quite similar features of MWS consisting of development delay, congenital heart disease, abdominal abnormalities, urogenital abnormalities, behavioral problems and so on, in which the distinctive craniofacial features can be more easily recognized.

CONCLUSIONS

Contiguous gene gain syndrome including entire ZEB2 characterized with similar multiple congenital anomalies of MWS and the distinctive craniofacial features is mainly caused by large 2q22 repeats including ZEB2 leading to dominant singe ZEB2 gene gain mutation, which is recommended to be named "Liu-Liang-Chung" syndrome. We diagnose this novel syndrome to distinguish it from MWS. Some variable additional features in the syndrome including remarkable growth and development retardation and protruding ears were recognized for the first time.

Clinical Characteristics and Novel ZEB2 Gene Mutation Analysis of Three Chinese Patients with Mowat-Wilson Syndrome

Purpose

Mowat-Wilson syndrome (MWS) is an autosomal dominant disease caused by a pathogenic variant of the ZEB2 gene. The main clinical manifestations include special facial features, Hirschsprung disease (HSCR), global developmental delay and other congenital malformations. Here, we summarize the clinical characteristics and genetic mutation analysis of three Chinese patients with MWS.

Patients and Methods

The clinical characteristics of the patients were monitored and the treatment effect was followed up. DNA was extracted from peripheral blood and analyzed by sequencing. Whole exome sequencing was then performed.

Results

Three novel ZEB2 gene mutations were identified in 3 patients (c.1147_1150dupGAAC, p.Q384Rfs*7, c.1137_1146del TAGTATGTCT, p.S380Nfs *13 and c.2718delT, p.A907Lfs*23). They all had special facial features, intellectual disability, developmental delay, microcephaly, structural brain abnormalities and other symptoms. After long-term regular rehabilitation treatment, the development quotient of each functional area of the patient was slightly improved.

Conclusion

Our study expanded the mutation spectrum of ZEB2 and enriched our understanding of the clinical features of MWS. It also shows that long-term standardized treatment is of great significance for the prognosis of patients.

Mutated Transcripts of ZEB2 Do Not Undergo Nonsense-Mediated Decay in Mowat-Wilson Syndrome

Introduction

Mowat-Wilson syndrome (MWS) is an autosomal-dominant complex developmental disorder characterized by distinctive facial appearance, intellectual disability, epilepsy, and various clinically heterogeneous abnormalities reminiscent of neurocristopathies. MWS is caused by haploinsufficiency of ZEB2 due to heterozygous point mutations and copy number variations.

Case Presentation

We report on two unrelated affected individuals with novel ZEB2indel mutations, molecularly confirming the diagnosis of MWS. Quantitative real-time polymerase chain reaction (PCR) for the comparison of total transcript levels and allele-specific quantitative real-time PCR were also performed and demonstrated that the truncating mutations did not lead to nonsense-mediated decay as expected.

Conclusion

ZEB2 encodes a multifunctional pleiotropic protein. Novel mutations in ZEB2 should be reported in order that genotype-phenotype correlations might be established in this clinically heterogeneous syndrome. Further cDNA and protein studies may help elucidate the underlying pathogenetic mechanisms of MWS since nonsense-mediated RNA decay was found to be absent in only a few studies including this study.

Zeb2 DNA-Binding Sites in Neuroprogenitor Cells Reveal Autoregulation and Affirm Neurodevelopmental Defects, Including in Mowat-Wilson Syndrome

Functional perturbation and action mechanism studies have shown that the transcription factor Zeb2 controls cell fate decisions, differentiation, and/or maturation in multiple cell lineages in embryos and after birth. In cultured embryonic stem cells (ESCs), Zeb2’s mRNA/protein upregulation is necessary for the exit from primed pluripotency and for entering general and neural differentiation. We edited mouse ESCs to produce Flag-V5 epitope-tagged Zeb2 protein from one endogenous allele. Using chromatin immunoprecipitation coupled with sequencing (ChIP-seq), we mapped 2432 DNA-binding sites for this tagged Zeb2 in ESC-derived neuroprogenitor cells (NPCs). A new, major binding site maps promoter-proximal to Zeb2 itself. The homozygous deletion of this site demonstrates that autoregulation of Zeb2 is necessary to elicit the appropriate Zeb2-dependent effects in ESC-to-NPC differentiation. We have also cross-referenced all the mapped Zeb2 binding sites with previously obtained transcriptome data from Zeb2 perturbations in ESC-derived NPCs, GABAergic interneurons from the ventral forebrain of mouse embryos, and stem/progenitor cells from the post-natal ventricular-subventricular zone (V-SVZ) in mouse forebrain, respectively. Despite the different characteristics of each of these neurogenic systems, we found interesting target gene overlaps. In addition, our study also contributes to explaining developmental disorders, including Mowat-Wilson syndrome caused by ZEB2 deficiency, and also other monogenic syndromes.

ZEB2 controls kidney stromal progenitor differentiation and inhibits abnormal myofibroblast expansion and kidney fibrosis

FOXD1+ cell-derived stromal cells give rise to pericytes and fibroblasts that support the kidney vasculature and interstitium but are also major precursors of myofibroblasts. ZEB2 is a SMAD-interacting transcription factor that is expressed in developing kidney stromal progenitors. Here we show that Zeb2 is essential for normal FOXD1+ stromal progenitor development. Specific conditional knockout of mouse Zeb2 in FOXD1+ stromal progenitors (Zeb2 cKO) leads to abnormal interstitial stromal cell development, differentiation, and kidney fibrosis. Immunofluorescent staining analyses revealed abnormal expression of interstitial stromal cell markers MEIS1/2/3, CDKN1C, and CSPG4 (NG2) in newborn and 3-week-old Zeb2-cKO mouse kidneys. Zeb2-deficient FOXD1+ stromal progenitors also took on a myofibroblast fate that led to kidney fibrosis and kidney failure. Cell marker studies further confirmed that these myofibroblasts expressed pericyte and resident fibroblast markers, including PDGFRβ, CSPG4, desmin, GLI1, and NT5E. Notably, increased interstitial collagen deposition associated with loss of Zeb2 in FOXD1+ stromal progenitors was accompanied by increased expression of activated SMAD1/5/8, SMAD2/3, SMAD4, and AXIN2. Thus, our study identifies a key role of ZEB2 in maintaining the cell fate of FOXD1+ stromal progenitors during kidney development, whereas loss of ZEB2 leads to differentiation of FOXD1+ stromal progenitors into myofibroblasts and kidney fibrosis.

Difficulties in the differential diagnosis of Angelman’s syndrome

Angelman syndrome is a rare neurogenetic disease caused by the loss of the function of the maternal allele of the UBE3A gene on chromosome 15 (site 15q11.2–q13) and is characterized by severe mental retardation, lack of speech, epilepsy, microcephaly and a characteristic facial phenotype with a unique behavior in the form of frequent laughter. The combination of microcephaly, epilepsy, speechlessness and mental retardation poses a problem for differential diagnosis with many genetic diseases presenting with similar symptoms. Epileptic encephalopathy due to CDKL5 gene mutation and Rett syndrome have the greatest similarity. The hallmark of Angelman syndrome are laughter attacks and specific EEG changes. The authors have presented a table of the differential diagnosis of Angelman syndrome with some phenotypically similar genetic syndromes, indicating the most significant distinguishing features, which should facilitate for the pediatrician and neurologist the diagnostic path of establishing the correct diagnosis.

First Case Report of Developmental Bilateral Cataract with a Novel Mutation in the ZEB2 Gene Observed in Mowat-Wilson Syndrome

Background: Mowat-Wilson syndrome (MWS) is extremely rare multisystemic autosomal dominant disorder caused by mutations in the Zinc Finger E-Box Binding Homeobox 2 (ZEB2) gene. Ocular pathologies are one of the symptoms that appear in the clinical picture of MWS individuals, but not many have been described so far. Pathologies such as optic nerve or retinal epithelium atrophy, iris or optic disc coloboma as well as congenital cataracts have been most frequently described until now. Therefore, we would like to report the first case of bilateral developmental cataract in a 9-year-old girl with MWS who underwent successful cataract surgery with intraocular lens implantation. Case Presentation: A 9-year-old girl, diagnosed with p.Gln694Ter mutation in ZEB2 gene and suspicion of MWS was referred to the Children's Outpatient Ophthalmology Clinic for ophthalmological evaluation. Her previous assessments revealed abnormalities of the optic nerve discs. The patient was diagnosed with atrophy of the optic nerves, convergent strabismus, and with-the-rule astigmatism. One year later, during the follow-up visit, the patient was presented with decreased visual acuity (VA), developmental total cataract in the right eye and a developmental partial cataract in the left eye. This resulted in decreased VA confirmed by deteriorated responses in visual evoked potential (VEP) test. The girl underwent a two-stage procedure of cataract removal, first of one eye and then of the other eye with artificial lens implants. In the 2 years following the operation, no complications were observed and, most remarkably, VA improved significantly. Conclusions: The ZEB2 gene is primarily responsible for encoding the Smad interaction protein 1 (SIP1), which is involved in the proper development of various eye components. When mutated, it results in multilevel abnormalities, also in the proper lens formation, that prevent the child from normal vision development. This typically results in the formation of congenital cataracts in children with MWS syndrome, however, our case shows that it also leads to the formation of developmental cataracts. This is presumably due to the effect of the lack of SIP1 on other genes, altering their downstream expression and is a novel insight into the importance of the SIP1 in the occurrence of ocular pathologies. To the best of our knowledge, this is the first case of bilateral developmental cataract in the context of MWS. Moreover, a novel mutation (p.Gln694Ter) in the ZEB2 gene was found corresponding to this syndrome entity. This report allows us to gain a more comprehensive insight into the genetic spectrum and the corresponding phenotypic features in MWS syndrome patients.

Physical, language, neurodevelopment and phenotype-genotype correlation of Chinese patients with Mowat-Wilson syndrome

Background: To report detailed knowledge about the clinical manifestations, genetic spectrum as well as physical, language, neurodevelopment features and genotype-phenotype correlations of Chinese patients with Mowat-Wilson syndrome (MWS).

Methods: We retrospectively collected and analyzed clinical data for twenty-two patients with molecularly confirmed diagnoses. We used Gesell Developmental Schedules (GDS) to assess their neurodevelopment and the Diagnostic Receptive and Expressive Assessment of Mandarin-Infant & Toddler (DREAM-IT) to evaluate their language ability and compared the data with the two types of underlying pathogenic variations.

Results: The height and weight of all patients were below the 75th percentile, and microcephaly was observed in 16 of 22 patients (72.7%). Four patients carrying chromosome deletions encompassing the ZEB2 gene were more severely affected. All MWS patients exhibited better performance in cognitive play and social communication than in receptive and expressive language. In the receptive language area, the types of words that children with MWS understood most were nouns, followed by adjectives and verbs.

Conclusion: This study delineated the phenotypic spectrum of the largest MWS cohort in China and provided comprehensive profiling of their physical, language, neurodevelopment features and genotype-phenotype correlations.

Mowat-Wilson Syndrome as a Differential Diagnosis in Patients with Congenital Heart Defects and Dysmorphic Facies

Mowat-Wilson syndrome is a rare, autosomal dominant neurodevelopmental disorder characterized by distinctive facial gestalt and intellectual disability that is often associated with microcephaly, seizures and multiple congenital anomalies, mainly heart defects. More than 350 patients and 180 genetic variants in the ZEB2 gene, have been reported with an estimated frequency of 1 per 70,000 births. Here we report a Colombian female patient with facial gestalt, intellectual disability, microcephaly, congenital heart defects, hypothyroidism and middle ear defect associated with the nonsense pathogenic variant c.2761C>T (p.Arg921Ter) in the ZEB2 gene. This case contributes to the understanding of the clinical complications and the natural history of this complex and clinically heterogeneous disorder but also to the awareness that patients with heart congenital defects and dysmorphic facies may present an underlying genetic disorder.

ZEB2 haploinsufficient Mowat-Wilson syndrome induced pluripotent stem cells show disrupted GABAergic transcriptional regulation and function

Mowat-Wilson syndrome (MWS) is a severe neurodevelopmental disorder caused by heterozygous variants in the gene encoding transcription factor ZEB2. Affected individuals present with structural brain abnormalities, speech delay and epilepsy. In mice, conditional loss of Zeb2 causes hippocampal degeneration, altered migration and differentiation of GABAergic interneurons, a heterogeneous population of mainly inhibitory neurons of importance for maintaining normal excitability. To get insights into GABAergic development and function in MWS we investigated ZEB2 haploinsufficient induced pluripotent stem cells (iPSC) of MWS subjects together with iPSC of healthy donors. Analysis of RNA-sequencing data at two time points of GABAergic development revealed an attenuated interneuronal identity in MWS subject derived iPSC with enrichment of differentially expressed genes required for transcriptional regulation, cell fate transition and forebrain patterning. The ZEB2 haploinsufficient neural stem cells (NSCs) showed downregulation of genes required for ventral telencephalon specification, such as FOXG1, accompanied by an impaired migratory capacity. Further differentiation into GABAergic interneuronal cells uncovered upregulation of transcription factors promoting pallial and excitatory neurons whereas cortical markers were downregulated. The differentially expressed genes formed a neural protein-protein network with extensive connections to well-established epilepsy genes. Analysis of electrophysiological properties in ZEB2 haploinsufficient GABAergic cells revealed overt perturbations manifested as impaired firing of repeated action potentials. Our iPSC model of ZEB2 haploinsufficient GABAergic development thus uncovers a dysregulated gene network leading to immature interneurons with mixed identity and altered electrophysiological properties, suggesting mechanisms contributing to the neuropathogenesis and seizures in MWS.

Genetics behind Cerebral Disease with Ocular Comorbidity: Finding Parallels between the Brain and Eye Molecular Pathology

Cerebral visual impairments (CVIs) is an umbrella term that categorizes miscellaneous visual defects with parallel genetic brain disorders. While the manifestations of CVIs are diverse and ambiguous, molecular diagnostics stand out as a powerful approach for understanding pathomechanisms in CVIs. Nevertheless, the characterization of CVI disease cohorts has been fragmented and lacks integration. By revisiting the genome-wide and phenome-wide association studies (GWAS and PheWAS), we clustered a handful of renowned CVIs into five ontology groups, namely ciliopathies (Joubert syndrome, Bardet-Biedl syndrome, Alstrom syndrome), demyelination diseases (multiple sclerosis, Alexander disease, Pelizaeus-Merzbacher disease), transcriptional deregulation diseases (Mowat-Wilson disease, Pitt-Hopkins disease, Rett syndrome, Cockayne syndrome, X-linked alpha-thalassaemia mental retardation), compromised peroxisome disorders (Zellweger spectrum disorder, Refsum disease), and channelopathies (neuromyelitis optica spectrum disorder), and reviewed several mutation hotspots currently found to be associated with the CVIs. Moreover, we discussed the common manifestations in the brain and the eye, and collated animal study findings to discuss plausible gene editing strategies for future CVI correction.

Deletion of 2q22.2q22.3 in Mowat–Wilson Syndrome: A Case Report and Review of the Literature

Mowat–Wilson syndrome (MWS; Online Mendelian Inheritance in Man #235730) is a rare disorder characterized by developmental delay, severe intellectual disability, distinctive facial dysmorphism, and multiple associated abnormalities caused by mutation or deletion of ZEB2 gene. Here we report a 13 months old boy with characteristic facial features of MWS, global developmental delay, peculiar behavior, microcephaly, and hypospadias. Array comparative genomic hybridization (CGH) revealed a 5.7-Mb deletion of 2q22.2q22.3 region. The deletion contains 10 genes, including LRP1B, KYNU, ARHGAP15, GTDC1, ZEB2, ZEB2-AS1, TEX41, MBD5, ORC4, and ACVR2A. Our case shows the utility of array CGH in identifying such complex phenotype.

Identification of MMACHC and ZEB2 mutations causing coexistent cobalamin C disease and Mowat-Wilson syndrome in a 2-year-old girl

Cobalamin C (cblC) disease and Mowat-Wilson syndrome (MWS) are rare hereditary diseases. To date, there have been no reports of people suffering from these two genetic diseases, or whether there is any correlation between the two diseases. We reported a 2-year-old girl with both cblC disease and MWS. The patient initially manifested as slow weight gain, hypotonia, broad nasal bridge, high forehead, high palate arch, ear crease, patent ductus arteriosus, atrial and ventricular septal defect and bilateral mild ventriculomegaly in the neonatal period. However, as the baby grew older, the typical facial features became more prominent, and overall developmental delays were noted at the subsequent follow-up, with the motor and cognitive development significantly lagging behind that of other children of the same age. At 26 days old, laboratory tests revealed remarkably elevated levels of serum homocysteine, C3/C2 and urine organic acid. Whole-exome sequencing detected compound heterozygous variants in MMACHC, including one previously reported mutation [c.609G > A (p.W203X) and a novel missense mutation[ c.643 T > C (p.Y215H)]. The computer simulations of the protein structure analysis of the novel missense mutation showed the variant p.Y215H replaced a neutral amino acid with a strongly basic lysine, which broken the local structure by changing the carbon chain skeleton and decreasing the interaction with adjacent amino acid. This is expected to damage the utilization of vitamin B12 and influence the synthesis of AdoCbl and MeCbl, contributing to its pathogenicity. Thus, clinical and genetic examinations confirmed the cblC disease. Another heterozygous variant in ZEB2 [NM_014795; loss1(exon:2-10)(all); 127901 bp] was detected by whole-exome sequencing. The heterozygous 3.04 Mb deletion in EB2 [GRCH37]del(2)(q22.2q22.3) (chr2:142237964-145274917) was also confirmed by genome-wide copy number variations (CNVs) scan, which was pathogenic and led to the diagnosis of Mowat-Wilson syndrome. The biochemical indicators associated with cblC disease in the patient were well controlled after treatment with vitamin B12 and betaine. Here, a patient with coexisting cblC disease and MWS caused by different pathogenic genes was reported, which enriched the clinical research on these two rare genetic diseases.

Three Novel De Novo ZEB2 Variants Identified in Three Unrelated Chinese Patients With Mowat-Wilson Syndrome and A Systematic Review

Background: ZEB2 gene mutations or deletions cause Mowat-Wilson syndrome (MWS), which is characterized by distinctive facial features, global developmental delay, intellectual disability, epilepsy, friendly and happy personalities, congenital heart disease, Hirschsprung disease and multiple congenital anomalies. Currently, more than 300 MWS patients have been described in the literature, and nearly 280 variants in ZEB2 have been identified. Methods: In this study, we report three unrelated Chinese patients presenting multiple congenital anomalies that were consistent with those of MWS. Whole-exome sequencing (WES) was used to identify the causative variants. Results: WES identified two novel de novo frameshift variants in ZEB2 (NM_014795.4:c.2136delC, p. Lys713Serfs*3 and c.2740delG, p. Gln914Argfs*16) in patients 1 and 2, respectively, and a novel de novo splicing variant in ZEB2 (NM_014795.4:c.808-2delA) in patient 3, all of which were confirmed by Sanger sequencing. Next, we systematically reviewed the clinical characteristics of Chinese and Caucasian MWS patients. We revealed a higher incidence of constipation in Chinese MWS patients compared to that previously reported in Caucasian cohorts, while the incidence of Hirschsprung disease and happy demeanor was lower in Chinese MWS patients and that epilepsy in Chinese MWS patients could be well-controlled compared to that in Caucasian MWS individuals. Conclusion: Our study expanded the mutation spectrum of ZEB2 and enriched our understanding of the clinical characteristics of MWS. Definitive genetic diagnosis is beneficial for the genetic counseling and clinical management of individuals with MWS.

Mowat-Wilson syndrome presenting with Shone's complex cardiac anomaly

A female infant, who was diagnosed antenatally with complex heart disease, confirmed to be Shone's complex postnatally, underwent bilateral pulmonary artery banding, patent ductus arteriosus stent insertion and balloon aortic valvuloplasty soon after birth. She was found to have bilateral megaureters, left hydronephrosis and asplenia. She was on lifelong prophylactic antibiotics and extra vaccines. She had two episodes of pseudo-obstruction of the small bowel, but barium follow-through was normal. She also had a large bowel obstruction and work-up for Hirschsprung disease confirmed the diagnosis. It was noticed that she had developmental delay and hypotonia, together with subtle dysmorphism. She also had failure to thrive and difficulty feeding. Exome sequencing revealed a diagnosis of Mowat-Wilson syndrome (MWS). This case shows a previously undescribed association of Shone's complex, a complex left-sided obstructive heart defect, and MWS. It also highlights the usefulness of trio-exome sequencing in detecting such rare mutations.

Positive selection in noncoding genomic regions of vocal learning birds is associated with genes implicated in vocal learning and speech functions in humans

Vocal learning, the ability to imitate sounds from conspecifics and the environment, is a key component of human spoken language and learned song in three independently evolved avian groups—oscine songbirds, parrots, and hummingbirds. Humans and each of these three bird clades exhibit specialized behavioral, neuroanatomical, and brain gene expression convergence related to vocal learning, speech, and song. To understand the evolutionary basis of vocal learning gene specializations and convergence, we searched for and identified accelerated genomic regions (ARs), a marker of positive selection, specific to vocal learning birds. We found avian vocal learner-specific ARs, and they were enriched in noncoding regions near genes with known speech functions or brain gene expression specializations in humans and vocal learning birds, including FOXP2, NEUROD6, ZEB2, and MEF2C, and near genes with major neurodevelopmental functions, including NR2F1, NRP2, and BCL11B. We also found enrichment near the SFARI class S genes associated with syndromic vocal communication forms of autism spectrum disorders. These findings reveal strong candidate noncoding regions near genes for the evolutionary adaptations that distinguish vocal learning species from their close vocal nonlearning relatives and provide further evidence of molecular convergence between birdsong and human spoken language.

Further delineation and long-term evolution of electroclinical phenotype in Mowat Wilson Syndrome. A longitudinal study in 40 individuals

BACKGROUND

Epilepsy is a main feature of Mowat Wilson Syndrome (MWS), a congenital malformation syndrome caused by ZEB2 variants. The aim of this study was to investigate the long-term evolution of the electroclinical phenotype of MWS in a large population.

METHODS

Forty-individuals with a genetically confirmed diagnosis were enrolled. Three age groups were identified (t1 = 0-4; t2 = 5-12; t3 = >13 years); clinical data and EEG records were collected, analyzed, and compared for age group. Video-EEG recorded seizures were reviewed.

RESULTS

Thirty-six of 40 individuals had epilepsy, of whom 35/35 aged >5 years. Almost all (35/36) presented focal seizures at onset (mean age at onset 3.4 ± 2.3 SD) that persisted, reduced in frequency, in 7/22 individuals after the age of 13. Absences occurred in 22/36 (mean age at onset 7.2 ± 0.9 SD); no one had absences before 6 and over 16 years old. Paroxysmal interictal abnormalities in sleep also followed an age-dependent evolution with a significant increase in frequency at school age (p = 0.002) and a reduction during adolescence (p = 0.008). Electrical Status Epilepticus during Sleep occurred in 14/36 (13/14 aged 5-13 years old at onset). Seven focal seizure ictal video-EEGs were collected: all were long-lasting and more visible clinical signs were often preceded by prolonged electrical and/or subtle (erratic head and eye orientation) seizures. Valproic acid was confirmed as the most widely used and effective drug, followed by levetiracetam.

CONCLUSIONS

Epilepsy is a major sign of MWS with a characteristic, age-dependent, electroclinical pattern. Improvement with adolescence/adulthood is usually observed. Our data strengthen the hypothesis of a GABAergic transmission imbalance underlying ZEB2-related epilepsy.

Angelman Syndrome and Angelman-like Syndromes Share the Same Calcium-Related Gene Signatures

Angelman-like syndromes are a group of neurodevelopmental disorders that entail clinical presentation similar to Angelman Syndrome (AS). In our previous study, we showed that calcium signaling is disrupted in AS, and we identified calcium-target and calcium-regulating gene signatures that are able to differentiate between AS and their controls in different models. In the herein study, we evaluated these sets of calcium-target and calcium-regulating genes as signatures of AS-like and non-AS-like syndromes. We collected a number of RNA-seq datasets of various AS-like and non-AS-like syndromes and performed Principle Component Analysis (PCA) separately on the two sets of signature genes to visualize the distribution of samples on the PC1-PC2 plane. In addition to the evaluation of calcium signature genes, we performed differential gene expression analyses to identify calcium-related genes dysregulated in each of the studied syndromes. These analyses showed that the calcium-target and calcium-regulating signatures differentiate well between AS-like syndromes and their controls. However, in spite of the fact that many of the non-AS-like syndromes have multiple differentially expressed calcium-related genes, the calcium signatures were not efficient classifiers for non-AS-like neurodevelopmental disorders. These results show that features based on clinical presentation are reflected in signatures derived from bioinformatics analyses and suggest the use of bioinformatics as a tool for classification.

A Chinese Boy with Mowat-Wilson Syndrome Caused by a 10 bp Deletion in the ZEB2 Gene

Purpose

Mowat–Wilson syndrome (MWS) is a rare complex malformation syndrome which is characterized by typical facial dysmorphism, moderate to severe intellectual disability, global developmental delay, and multiple congenital anomalies. Here, we summarize the clinical characteristics and gene mutation analysis of a Chinese boy with MWS.

Patients and Methods

The clinical features of the patient were monitored. DNA extracted from peripheral blood was subjected to sequencing analysis. Then, the whole-exome sequencing was performed.

Results

A novel deletion mutation (c.1137_1146del TAGTATGTCT) was identified in exon 8 of the ZEB2 gene. The deletion mutation was predicted to produce a truncated protein (p.S380Nfs*13), resulting in haploinsufficiency. The patient presented with short stature, microcephaly, congenital heart defects, cryptorchidism, corpus callosum agenesis, global developmental delay, and intellectual disability. Furthermore, he demonstrated bilateral sensorineural hearing loss. This manifestation is less common in MWS. It is first reported in Chinese patients with MWS. Clinical follow-up showed that the facial features of MWS developed with time. The facial features of the patient were not obvious except for the uplifted ear lobes at the age of 3 months. At the age of 22 months, the facial characteristics of the patient included ocular hypertelorism, frontal bossing, rounded nasal tip, sparse eyebrows, prominent chin, widely spaced teeth, and uplifted ear lobes with a central depression.

Conclusion

A novel deletion mutation of the ZEB2 gene was identified. This work contributes to expanding the mutation spectra of MWS. Our results may reflect the variability of the phenotype in MWS.

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Targeted chromatin conformation analysis identifies novel distal neural enhancers of ZEB2 in pluripotent stem cell differentiation

The transcription factor zinc finger E-box binding protein 2 (ZEB2) controls embryonic and adult cell fate decisions and cellular maturation in many stem/progenitor cell types. Defects in these processes in specific cell types underlie several aspects of Mowat–Wilson syndrome (MOWS), which is caused by ZEB2 haplo-insufficiency. Human ZEB2, like mouse Zeb2, is located on chromosome 2 downstream of a ±3.5 Mb-long gene-desert, lacking any protein-coding gene. Using temporal targeted chromatin capture (T2C), we show major chromatin structural changes based on mapping in-cis proximities between the ZEB2 promoter and this gene desert during neural differentiation of human-induced pluripotent stem cells, including at early neuroprogenitor cell (NPC)/rosette state, where ZEB2 mRNA levels increase significantly. Combining T2C with histone-3 acetylation mapping, we identified three novel candidate enhancers about 500 kb upstream of the ZEB2 transcription start site. Functional luciferase-based assays in heterologous cells and NPCs reveal co-operation between these three enhancers. This study is the first to document in-cis Regulatory Elements located in ZEB2’s gene desert. The results further show the usability of T2C for future studies of ZEB2 REs in differentiation and maturation of multiple cell types and the molecular characterization of newly identified MOWS patients that lack mutations in ZEB2 protein-coding exons.

ZEB2, the Mowat-Wilson Syndrome Transcription Factor: Confirmations, Novel Functions, and Continuing Surprises

After its publication in 1999 as a DNA-binding and SMAD-binding transcription factor (TF) that co-determines cell fate in amphibian embryos, ZEB2 was from 2003 studied by embryologists mainly by documenting the consequences of conditional, cell-type specific Zeb2 knockout (cKO) in mice. In between, it was further identified as causal gene causing Mowat-Wilson Syndrome (MOWS) and novel regulator of epithelial-mesenchymal transition (EMT). ZEB2's functions and action mechanisms in mouse embryos were first addressed in its main sites of expression, with focus on those that helped to explain neurodevelopmental and neural crest defects seen in MOWS patients. By doing so, ZEB2 was identified in the forebrain as the first TF that determined timing of neuro-/gliogenesis, and thereby also the extent of different layers of the cortex, in a cell non-autonomous fashion, i.e., by its cell-intrinsic control within neurons of neuron-to-progenitor paracrine signaling. Transcriptomics-based phenotyping of Zeb2 mutant mouse cells have identified large sets of intact-ZEB2 dependent genes, and the cKO approaches also moved to post-natal brain development and diverse other systems in adult mice, including hematopoiesis and various cell types of the immune system. These new studies start to highlight the important adult roles of ZEB2 in cell-cell communication, including after challenge, e.g., in the infarcted heart and fibrotic liver. Such studies may further evolve towards those documenting the roles of ZEB2 in cell-based repair of injured tissue and organs, downstream of actions of diverse growth factors, which recapitulate developmental signaling principles in the injured sites. Evident questions are about ZEB2's direct target genes, its various partners, and ZEB2 as a candidate modifier gene, e.g., in other (neuro)developmental disorders, but also the accurate transcriptional and epigenetic regulation of its mRNA expression sites and levels. Other questions start to address ZEB2's function as a niche-controlling regulatory TF of also other cell types, in part by its modulation of growth factor responses (e.g., TGFβ/BMP, Wnt, Notch). Furthermore, growing numbers of mapped missense as well as protein non-coding mutations in MOWS patients are becoming available and inspire the design of new animal model and pluripotent stem cell-based systems. This review attempts to summarize in detail, albeit without discussing ZEB2's role in cancer, hematopoiesis, and its emerging roles in the immune system, how intense ZEB2 research has arrived at this exciting intersection.

Neurological Phenotype of Mowat-Wilson Syndrome

Mowat-Wilson Syndrome (MWS) (OMIM # 235730) is a rare disorder due to ZEB2 gene defects (heterozygous mutation or deletion). The ZEB2 gene is a widely expressed regulatory gene, extremely important for the proper prenatal development. MWS is characterized by a specific facial gestalt and multiple musculoskeletal, cardiac, gastrointestinal, and urogenital anomalies. The nervous system involvement is extensive and constitutes one of the main features in MWS, heavily affecting prognosis and life quality of affected individuals. This review aims to comprehensively organize and discuss the neurological and neurodevelopmental phenotype of MWS. First, we will describe the role of ZEB2 in the formation and development of the nervous system by reviewing the preclinical studies in this regard. ZEB2 regulates the neural crest cell differentiation and migration, as well as in the modulation of GABAergic transmission. This leads to different degrees of structural and functional impairment that have been explored and deepened by various authors over the years. Subsequently, the different neurological aspects of MWS (head and brain malformations, epilepsy, sleep disorders, and enteric and peripheral nervous system involvement, as well as developmental, cognitive, and behavioral features) will be faced one at a time and extensively examined from both a clinical and etiopathogenetic point of view, linking them to the ZEB2 related pathways.

A Case Report of a Prenatally Missed Mowat-Wilson Syndrome With Isolated Corpus Callosum Agenesis

Mowat-Wilson syndrome (MWS) is an autosomal dominant genetic disorder caused by ZEB2 gene mutations, manifesting with unique facial characteristics, moderate to severe intellectual problems, and congenital malformations as Hirschsprung disease, genital and ophthalmological anomalies, and congenital cardiac anomalies. Herein, a case of 1-year-old boy with isolated agenesis of corpus callosum (IACC) in the prenatal period is presented. He was admitted postnatally with Hirschsprung disease (HSCR), hypertelorism, uplifted earlobes, deeply set eyes, frontal bossing, oval-shaped nasal tip, ''M'' shaped upper lip, opened mouth and prominent chin, and developmental delay. Hence, MWS was primarily considered and confirmed by the ZEB2 gene mutation analysis. His karyotype was normal. He had a history of having a prenatally terminated brother with similar features. Antenatally detected IACC should prompt a detailed investigation including karyotype and microarray; even if they are normal then whole exome sequencing (WES) should be done.

The Role of ZEB2 in Human CD8 T Lymphocytes: Clinical and Cellular Immune Profiling in Mowat-Wilson Syndrome

The Zeb2 gene encodes a transcription factor (ZEB2) that acts as an important immune mediator in mice, where it is expressed in early-activated effector CD8 T cells, and limits effector differentiation. Zeb2 homozygous knockout mice have deficits in CD8 T cells and NK cells. Mowat–Wilson syndrome (MWS) is a rare genetic disease resulting from heterozygous mutations in ZEB2 causing disease by haploinsufficiency. Whether ZEB2 exhibits similar expression patterns in human CD8 T cells is unknown, and MWS patients have not been comprehensively studied to identify changes in CD8 lymphocytes and NK cells, or manifestations of immunodeficiency. By using transcriptomic assessment, we demonstrated that ZEB2 is expressed in early-activated effector CD8 T cells of healthy human volunteers following vaccinia inoculation and found evidence of a role for TGFß-1/SMAD signaling in these cells. A broad immunological assessment of six genetically diagnosed MWS patients identified two patients with a history of recurrent sinopulmonary infections, one of whom had recurrent oral candidiasis, one with lymphopenia, two with thrombocytopenia and three with detectable anti-nuclear antibodies. Immunoglobulin levels, including functional antibody responses to protein and polysaccharide vaccination, were normal. The MWS patients had a significantly lower CD8 T cell subset as % of lymphocytes, compared to healthy controls (median 16.4% vs. 25%, p = 0.0048), and resulting increased CD4:CD8 ratio (2.6 vs. 1.8; p = 0.038). CD8 T cells responded normally to mitogen stimulation in vitro and memory CD8 T cells exhibited normal proportions of subsets with important tissue-specific homing markers and cytotoxic effector molecules. There was a trend towards a decrease in the CD8 T effector memory subset (3.3% vs. 5.9%; p = 0.19). NK cell subsets were normal. This is the first evidence that ZEB2 is expressed in early-activated human effector CD8 T cells, and that haploinsufficiency of ZEB2 in MWS patients had a slight effect on immune function, skewing T cells away from CD8 differentiation. To date there is insufficient evidence to support an immunodeficiency occurring in MWS patients.

Clinical characteristics of Polish patients with molecularly confirmed Mowat-Wilson syndrome

Mowat-Wilson syndrome is a rare neurodevelopmental disorder caused by pathogenic variants in the ZEB2 gene, intragenic deletions of the ZEB2 gene, and microdeletions in the critical chromosomal region 2q22-23, where the ZEB2 gene is located. Mowat-Wilson syndrome is characterized by typical facial features that change with the age, severe developmental delay with intellectual disability, and multiple congenital abnormalities. The authors describe the clinical and genetic aspects of 28th patients with Mowat-Wilson syndrome diagnosed in Poland. Characteristic dysmorphic features, psychomotor retardation, intellectual disability, and congenital anomalies were present in all cases. The incidence of most common congenital anomalies (heart defect, Hirschsprung disease, brain defects) was similar to presented in literature. Epilepsy was less common compared to previously reported cases. Although the spectrum of disorders in patients with Mowat-Wilson syndrome is wide, knowledge of characteristic dysmorphic features awareness of accompanying abnormalities, especially intellectual disability, improves detection of the syndrome.

Interstitial Deletion of 2q22.2q22.3 Involving the Entire ZEB2 Gene in a Case of Mowat-Wilson Syndrome

Mowat-Wilson syndrome (MWS) is a rare autosomal dominant syndrome characterized by dysmorphic features, mental retardation, and congenital heart disease (CHD). MWS results from microdeletions of chromosome 2q23 or de novo SNVs involving the ZEB2 gene. Here, we report on an Egyptian MWS patient diagnosed by chromosomal microarray (CMA). A 1-year-old male child was referred to the CHD clinic, National Research Centre, presenting with dysmorphic features and CHD. The patient was referred to the human cytogenetics department for cytogenetic analysis and for screening of subtelomere rearrangements and microdeletion loci, using MLPA, and all revealed normal results. CMA revealed an interstitial 2.27-Mb microdeletion in chromosome 2q, involving the entire ZEB2 gene and other genes. This study emphasizes the significance of CMA in the detection of microdeletions/microduplications and as a screening tool in cases presenting with CHD and extracardiac manifestations. MWS should be suspected in patients presenting with the characteristic facial dysmorphism, developmental delay, seizures, Hirschsprung disease, and congenital heart anomalies, especially those involving the pulmonary arteries or pulmonary valves. It is recommended to include the ZEB2 locus in the MLPA microdeletions probes.

Profile of copper-associated DNA methylation and its association with incident acute coronary syndrome

Background

Acute coronary syndrome (ACS) is a cardiac emergency with high mortality. Exposure to high copper (Cu) concentration has been linked to ACS. However, whether DNA methylation contributes to the association between Cu and ACS is unclear.

Methods

We measured methylation level at > 485,000 cytosine-phosphoguanine sites (CpGs) of blood leukocytes using Human Methylation 450 Bead Chip and conducted a genome-wide meta-analysis of plasma Cu in a total of 1243 Chinese individuals. For plasma Cu-related CpGs, we evaluated their associations with the expression of nearby genes as well as major cardiovascular risk factors. Furthermore, we examined their longitudinal associations with incident ACS in the nested case-control study.

Results

We identified four novel Cu-associated CpGs (cg20995564, cg18608055, cg26470501 and cg05825244) within a 5% false discovery rate (FDR). DNA methylation level of cg18608055, cg26470501, and cg05825244 also showed significant correlations with expressions of SBNO2, BCL3, and EBF4 gene, respectively. Higher DNA methylation level at cg05825244 locus was associated with lower high-density lipoprotein cholesterol level and higher C-reactive protein level. Furthermore, we demonstrated that higher cg05825244 methylation level was associated with increased risk of ACS (odds ratio [OR], 1.23; 95% CI 1.02–1.48; P = 0.03).

Conclusions

We identified novel DNA methylation alterations associated with plasma Cu in Chinese populations and linked these loci to risk of ACS, providing new insights into the regulation of gene expression by Cu-related DNA methylation and suggesting a role for DNA methylation in the association between copper and ACS.

Genes causing congenital hydrocephalus: Their chromosomal characteristics of telomere proximity and DNA compositions

Congenital hydrocephalus (CH) is caused by genetic mutations, but whether factors impacting human genetic mutations are disease-specific remains elusive. Given two factors associated with high mutation rates, we reviewed how many disease-susceptible genes match with (i) proximity to telomeres or (ii) high adenine and thymine (A + T) content in human CH as compared to other disorders of the central nervous system (CNS). We extracted genomic information using a genome data viewer. Importantly, 98 of 108 genes causing CH satisfied (i) or (ii), resulting in >90% matching rate. However, such a high accordance no longer sustained as we checked two factors in Alzheimer's disease (AD) and/or familial Parkinson's disease (fPD), resulting in 84% and 59% matching, respectively. A disease-specific matching of telomere proximity or high A + T content predicts causative genes of CH much better than neurodegenerative diseases and other CNS conditions, likely due to sufficient number of known causative genes (n = 108) and precise determination and classification of the genotype and phenotype. Our analysis suggests a need for identifying genetic basis of both factors before human clinical studies, to prioritize putative genes found in preclinical models into the likely (meeting at least one) and more likely candidate (meeting both), which predisposes human genes to mutations.

Clinical and Molecular Spectrum of Four Patients Diagnosed with Mowat-Wilson Syndrome

Mowat-Wilson syndrome (MWS) is a rare autosomal dominant syndrome characterized by distinctive facial features, congenital heart defects, Hirschsprung disease, genitourinary anomalies, various structural brain anomalies, and intellectual disability. Pathogenic mutations that result in haploinsufficiency in the ZEB2 gene cause MWS. In this study, we aimed to evaluate the clinical features and molecular analysis results of 4 MWS patients. All patients were examined by an expert clinical geneticist. Dysmorphological abnormalities were recorded. Data including demographic, clinical, and laboratory findings were obtained from hospital records. ZEB2 gene analysis was performed using a Sanger sequencing method. All patients had typical facial features of MWS such as widely spaced eyes, broad eyebrows with a medial flare, low-hanging columella, prominent or pointed chin, open-mouth expression, and uplifted earlobes. Four different heterozygous mutations were identified; 2 mutations were frameshift (c.246_247delGGinsC, c.980_980delG), 1 was nonsense (c.2083C>T), and 1 was splice site (c.808-2A>G). Two of them (c.246_247delGGinsC, c.980_980delG) have not been previously reported in the literature. By defining 2 novel mutations, this study contributes to the molecular spectrum of MWS, while also providing a further insight for genetic counseling. It also demonstrates the importance of dysmorphological examination in clinical diagnosis.