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Objective: Neurocristopathies play a role as pathogenesis of Hirschsprung's disease and congenital heart diseases (CHDs). This study seeks to identify concomitant deformities, syndromes, and/or associations associated with Hirschsprung's disease warrant evaluation for CHDs through echocardiography. Materials and Methods: A retrospective analysis was conducted on Hirschsprung's disease patients at Siriraj Hospital between January 2006 and December 2022. Echocardiograms were performed when clinical symptoms, abnormal chest X-rays (CXR), desaturation, heart murmurs raised suspicions of cardiovascular anomalies. Results: Among 299 Hirschsprung's disease patients, 43 (14.4%) exhibited CHDs. The sensitivity of CXR (n=268) and echocardiograms (n=51) in diagnosing CHDs was 48.8% and 100%, respectively. Predominant CHD presentations included patent ductus arteriosus (n=29), atrial septal defects (n=18), and ventricular septal defects (n=15). The presence of concomitant deformities, syndromes and/or associations associated with Hirschsprung's disease significantly heightened the likelihood of concurrent CHDs (Odds ratio = 23.56, p < 0.001). Patients with Hirschsprung's disease and concomitant deformities (n=28) (excluding syndromic or chromosomal abnormalities) had 1.73 times the odds of CHDs (p = 0.262) compared to those without concomitant deformities. Patients with Hirschsprung's disease and Down syndrome (n=34) exhibited 77.78 times higher odds of CHDs (p < 0.001), while those with other syndromes and/or associations (n=6) had 13.03 times higher odds of CHDs (p = 0.005) compared to patients lacking these conditions. Conclusion: CHDs were identified in 14.4% of Hirschsprung's disease patients. Echocardiograms should be selectively employed in Hirschsprung's disease associated with Down syndrome, other syndromes, or concomitant deformities. [ABSTRACT FROM AUTHOR]

Objective: Neurocristopathies play a role as pathogenesis of Hirschsprung’s disease and congenital heart diseases (CHDs). This study seeks to identify concomitant deformities, syndromes, and/or associations associated with Hirschsprung’s disease warrant evaluation for CHDs through echocardiography. Materials and Methods: A retrospective analysis was conducted on Hirschsprung’s disease patients at Siriraj Hospital between January 2006 and December 2022. Echocardiograms were performed when clinical symptoms, abnormal chest X-rays (CXR), desaturation, heart murmurs raised suspicions of cardiovascular anomalies. Results: Among 299 Hirschsprung’s disease patients, 43 (14.4%) exhibited CHDs. The sensitivity of CXR (n=268) and echocardiograms (n=51) in diagnosing CHDs was 48.8% and 100%, respectively. Predominant CHD presentations included patent ductus arteriosus (n=29), atrial septal defects (n=18), and ventricular septal defects (n=15). The presence of concomitant deformities, syndromes and/or associations associated with Hirschsprung’s disease significantly heightened the likelihood of concurrent CHDs (Odds ratio = 23.56, p < 0.001). Patients with Hirschsprung’s disease and concomitant deformities (n=28) (excluding syndromic or chromosomal abnormalities) had 1.73 times the odds of CHDs (p = 0.262) compared to those without concomitant deformities. Patients with Hirschsprung’s disease and Down syndrome (n=34) exhibited 77.78 times higher odds of CHDs (p < 0.001), while those with other syndromes and/or associations (n=6) had 13.03 times higher odds of CHDs (p = 0.005) compared to patients lacking these conditions. Conclusion: CHDs were identified in 14.4% of Hirschsprung’s disease patients. Echocardiograms should be selectively employed in Hirschsprung’s disease associated with Down syndrome, other syndromes, or concomitant deformities.

Waardenburg syndrome (WS) is characterized by hearing loss and pigmentary abnormalities of the eyes, hair, and skin. The condition is genetically heterogeneous, and is classified into four clinical types differentiated by the presence of dystopia canthorum in type 1 and its absence in type 2. Additionally, limb musculoskeletal abnormalities and Hirschsprung disease differentiate types 3 and 4, respectively. Genes PAX3, MITF, SOX10, KITLG, EDNRB, and EDN3 are already known to be associated with WS. In WS, a certain degree of molecularly undetected patients remains, especially in type 2. This study aims to pinpoint causative variants using different NGS approaches in a cohort of 26 Brazilian probands with possible/probable diagnosis of WS1 (8) or WS2 (18). DNA from the patients was first analyzed by exome sequencing. Seven of these families were submitted to trio analysis. For inconclusive cases, we applied a targeted NGS panel targeting WS/neurocristopathies genes. Causative variants were detected in 20 of the 26 probands analyzed, these being five in PAX3, eight in MITF, two in SOX10, four in EDNRB, and one in ACTG1 (type 2 Baraitser-Winter syndrome, BWS2). In conclusion, in our cohort of patients, the detection rate of the causative variant was 77%, confirming the superior detection power of NGS in genetically heterogeneous diseases.

Synopsis: Primigravida at 14 weeks' gestation with expeditiously growing abdominal distension was revealed to be megacolon on MRI (suspicious case of adult Hirschsprung disease). [ABSTRACT FROM AUTHOR]

Waardenburg syndrome (WS) is characterized by hearing loss and pigmentary abnormalities of the eyes, hair, and skin. The condition is genetically heterogeneous, and is classified into four clinical types differentiated by the presence of dystopia canthorum in type 1 and its absence in type 2. Additionally, limb musculoskeletal abnormalities and Hirschsprung disease differentiate types 3 and 4, respectively. Genes PAX3, MITF, SOX10, KITLG, EDNRB, and EDN3 are already known to be associated with WS. In WS, a certain degree of molecularly undetected patients remains, especially in type 2. This study aims to pinpoint causative variants using different NGS approaches in a cohort of 26 Brazilian probands with possible/probable diagnosis of WS1 (8) or WS2 (18). DNA from the patients was first analyzed by exome sequencing. Seven of these families were submitted to trio analysis. For inconclusive cases, we applied a targeted NGS panel targeting WS/neurocristopathies genes. Causative variants were detected in 20 of the 26 probands analyzed, these being five in PAX3, eight in MITF, two in SOX10, four in EDNRB, and one in ACTG1 (type 2 Baraitser-Winter syndrome, BWS2). In conclusion, in our cohort of patients, the detection rate of the causative variant was 77%, confirming the superior detection power of NGS in genetically heterogeneous diseases. [ABSTRACT FROM AUTHOR]

Cardiovascular neurocristopathy is associated with abnormal migration and development of neural crest cells, impacting the neural and the human cardiovascular system and leading to diseases such as cardiomyopathy, aortic disease, and aortic valve dysfunction. With advancements in biomedical imaging tools, efforts are made to understand the underlying causes of cardiovascular neurocristopathy and develop new diagnostic methods, especially using machine learning or specifically its sub-branch deep learning models. This article provides a systematic survey of the literature related to machine/deep learning-based segmentation of the diseases mentioned above in computer tomography (CT), magnetic resonance imaging (MRI), X-rays, and echocardiogram (Echos) images. The review identified gaps and provides future directions, such as the need for better interpretable and explainable AI models, addressing the lack of publicly available datasets, standardizing the result reporting procedure for better repeatability of the result, and the development of standard performance measurement metrics. The general conclusion suggests that there is a need for multimodalities, multimodel, high-quality data sets, and open-source disease-specific dataspaces that will help develop trustworthy deep learning models that could be implemented in imaging devices/tools and provide medical-grade segmented outputs that will augment and speed up clinician decision making.

The neural crest is said to be the fourth germ layer in addition to the ectoderm, mesoderm and endoderm because of its ability to differentiate into a variety of cells that contribute to the various tissues of the vertebrate body. Neural crest cells (NCCs) can be divided into three functional groups: cranial NCCs, cardiac NCCs and trunk NCCs. Defects related to NCCs can contribute to a broad spectrum of syndromes known as neurocristopathies. Studies on the neural crest have been carried out using animal models such as Xenopus, chicks, and mice. However, the precise control of human NCC development has not been elucidated in detail due to species differences. Using induced pluripotent stem cell (iPSC) technology, we developed an in vitro disease model of neurocristopathy by inducing the differentiation of patient-derived iPSCs into NCCs and/or neural crest derivatives. It is now possible to address complicated questions regarding the pathogenetic mechanisms of neurocristopathies by characterizing cellular biological features and transcriptomes and by transplanting patient-derived NCCs in vivo. Here, we provide some examples that elucidate the pathophysiology of neurocristopathies using disease modeling via iPSCs.

Abstract Background Hirschsprung disease, the most important congenital colonic dysmotility in children results from neural crest migration, differentiation, proliferation, or apoptosis defects where the rearranged during transfection (RET)-Protooncogene pathway has a central role. Although palatal and retinal anomalies in the context of chromosomopathies and some mono−/oligogenic syndromes are reported associated with Hirschsprung disease the role of inactivating RET mutations in these cases is not clarified. Case presentation We report on a dysmorphic newborn with cleft palate and palatal synechia, who showed intestinal obstruction after 24 h of life. Transient ileostomy and surgical biopsies were performed to diagnose aganglionosis of the colon and last ileal loop. No chromosomal anomalies or copy number variations were found. We identified a paternal heterozygous germline mutation c.1852 T > C, which results in the substitution of cysteine by arginine in the RET-receptor tyrosine kinase (p.C618R mutation). There was no family history of Hirschsprung disease, but the father underwent surgery for medullary thyroid carcinoma and was affected by retinal dystrophy. Conclusions The occurrence of Hirschsprung disease and carcinoma shows how a single mutation may be responsible for adverse effects: gain and loss of function of the same receptor. Furthermore, it would be interesting to study its dual role in face and retina embryology, and to extend targeted investigations of RET hotspots in these developmental abnormalities to facilitate counselling, follow-up, and tumor prevention. Complex surgical procedures and genetic testing as well as socio-economic impact are a challenge for familiar compliance.

Jansen metaphyseal chondrodysplasia (JMC) is an ultra-rare disorder caused by constitutive activation of parathyroid hormone type 1 receptor (PTH1R). We sought to characterize the craniofacial phenotype of patients with the disease. Six patients with genetically confirmed JMC underwent comprehensive craniofacial phenotyping revealing a distinct facial appearance that prompted a cephalometric analysis demonstrating a pattern of mandibular retrognathia. Oral examination was notable for flat and shallow palate, delayed eruption pattern, and impacted maxillary teeth. Subclinical and/or mild hearing loss was noted in 4 of 5 patients studied. The most common etiology was conductive, likely due to overcrowding of epitympanum which impedes the normal vibration of ossicles to sound. Paranasal sinus obliteration was noted in 5 of 6 patients. Computed tomography (CT) scan evaluation of craniofacial bones revealed bilaterally symmetric expansile lesions with predominant involvement of neural crest cell (NCC)-derived bones. Bilateral narrowing of facial nerve canals, particularly at the labyrinthine segment, was seen in 5 of 6 patients when compared to age-matched controls; 1 patient presented with progressive facial nerve palsy. Sagittal suture craniosynostosis was present in 5 of 6 patients-one of whom had a history of cranial reconstruction for pansynostosis in infancy. All patients demonstrated a significant degree of upper airway stenosis, as well as a more anterior hyoid bone displacement. Two patients had a diagnosis of obstructive sleep apnea. 18F-NaF Positron-emission tomography (PET)-CT revealed increased uptake associated with the skull base and gnathic bones in all patients. In conclusion, this first detailed systematic evaluation of the craniofacial phenotype of patients with JMC demonstrates a distinct and pronounced phenotype that predominantly affects the NCC-derived cranial bones indicating a critical role of PTH1R signaling in their development. These affects can result in significant disease-related morbidity, include hearing loss, nerve compression, craniosynostosis, dentoskeletal malocclusion, and airway compromise; all of which require close monitoring., Competing Interests: All authors state that they have no conflicts of interest., (Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research 2024.)

Rationale: Congenital central hypoventilation syndrome (CCHS) is a rare autonomic disorder with altered regulation of breathing, heart rate (HR), and blood pressure (BP). Aberrant cerebral oxygenation in response to hypercapnia/hypoxia in CCHS raises the concern that altered cerebral autoregulation may contribute to CCHS-related, variably impaired neurodevelopment. Objectives: To evaluate cerebral autoregulation in response to orthostatic challenge in CCHS cases versus controls. Methods: CCHS and age- and sex-matched control subjects were studied with head-up tilt (HUT) testing to induce orthostatic stress. Fifty CCHS and 100 control HUT recordings were included. HR, BP, and cerebral oxygen saturation (regional oxygen saturation) were continuously monitored. The cerebral oximetry index (COx), a real-time measure of cerebral autoregulation based on these measures, was calculated. Measurements and Main Results: HUT resulted in a greater mean BP decrease from baseline in CCHS versus controls (11% vs. 6%; P < 0.05) and a diminished increase in HR in CCHS versus controls (11% vs. 18%; P < 0.01) in the 5 minutes after tilt-up. Despite a similar COx at baseline, orthostatic provocation within 5 minutes of tilt-up caused a 50% greater increase in COx (P < 0.01) and a 29% increase in minutes of impaired autoregulation (P < 0.02) in CCHS versus controls (4.0 vs. 3.1 min). Conclusions: Cerebral autoregulatory mechanisms appear to be intact in CCHS, but the greater hypotension observed in CCHS consequent to orthostatic provocation is associated with greater values of COx/impaired autoregulation when BP is below the lower limits of autoregulation. Effects of repeated orthostatic challenges in everyday living in CCHS necessitate further study to determine their influence on neurodevelopmental disease burden. [ABSTRACT FROM AUTHOR]

Background: The neural crest is a transient structure present in early embryogenesis. Cephalic neural crest cells migrate into the pharyngeal arches and the frontonasal process that becomes the forehead and midfacial structures. They also contribute to forming the media of the arteries of the circle of Willis and their branches. The cardiac neural crest produces vascular smooth muscle cells in the ascending aorta, cardiac septum and coronary arteries. Methods: In this review, we evaluate the role of the neural crest in moyamoya disease and the pathological implications from the concurrence of moyamoya disease and cardiovascular diseases from the point of view of neural crest cell distributions. Results: Midline craniofacial and central nervous system anomalies with eye anomalies, morning glory disc anomaly in patients with moyamoya disease can both be explained as a subtype of cephalic neurocristopathy. Further, the association between moyamoya disease and cardiac manifestations (congenital cardiac defects and coronary artery disease) have also been reported. Both the cephalic neural crest and cardiac neural crest contribute to these concurrent arterial diseases, as cardio-cephalic neurocristopathy. Conclusion: The concept of cephalic/cardio-cephalic neurocristopathy provides a new perspective to understanding the underlying aetiological associations and to developing future therapeutic approaches for concomitant moyamoya disease and cardiovascular diseases. [ABSTRACT FROM AUTHOR]

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Protein interaction is critical molecular regulatory activity underlining cellular functions and precise cell fate choices. Using TWIST1 BioID-proximity-labeling and network propagation analyses, we discovered and characterized a TWIST-chromatin regulatory module (TWIST1-CRM) in the neural crest cells (NCC). Combinatorial perturbation of core members of TWIST1-CRM: TWIST1, CHD7, CHD8, and WHSC1 in cell models and mouse embryos revealed that loss of the function of the regulatory module resulted in abnormal differentiation of NCCs and compromised craniofacial tissue patterning. Following NCC delamination, low level of TWIST1-CRM activity is instrumental to stabilize the early NCC signatures and migratory potential by repressing the neural stem cell programs. High level of TWIST1 module activity at later phases commits the cells to the ectomesenchyme. Our study further revealed the functional interdependency of TWIST1 and potential neurocristopathy factors in NCC development.

In the last few years, the role of non-coding regulatory elements and their involvement in human disease have received great attention. Among the non-coding regulatory sequences, enhancers are particularly important for the proper establishment of cell type–specific gene-expression programs. Furthermore, the disruption of enhancers can lead to human disease through two main mechanisms: (i) Mutations or copy number variants can directly alter the enhancer sequences and thereby affect expression of their target genes; (ii) structural variants can provoke changes in 3-D chromatin organization that alter neither the enhancers nor their target genes, but rather the physical communication between them. In this review, these pathomechanisms are mostly discussed in the context of neurocristopathies, congenital disorders caused by defects that occur during neural crest development. We highlight why, due to its contribution to multiple tissues and organs, the neural crest represents an important, yet understudied, cell type involved in multiple congenital disorders. Moreover, we discuss currently available resources and experimental models for the study of human neurocristopathies. Last, we provide some practical guidelines that can be followed when investigating human neurocristopathies caused by structural variants. Importantly, these guidelines can be useful not only to uncover the etiology of human neurocristopathies, but also of other human congenital disorders in which enhancer disruption is involved.

The orbit houses and protects the ocular globe and the supporting structures, and occupies a strategic position below the anterior skull base and adjacent to the paranasal sinuses. Its embryologic origins are inextricably intertwined with those of the central nervous system, skull base, and face. Although the orbit contains important contributions from four germ cell layers (surface ectoderm, neuroectoderm, neural crest, and mesoderm), a significant majority originate from the neural crest cells. The bones of the orbit, face, and anterior cranial vault are mostly neural crest in origin. The majority of the bones of the skull base are formed through endochondral ossification, whereas the cranial vault is formed through intramembranous ossification. Familiarity with the embryology and fetal development of the orbit can aid in understanding its anatomy, as well as many developmental anomalies and pathologic conditions that affect the orbit. [ABSTRACT FROM AUTHOR]

In inflammatory dermatoses, dermal melanophages (MLP) are ascribed to "pigment incontinence," with melanin "dropping down" from the epidermis. Although this is analogous to the "dropping down" of melanocytic nevus cells (Abtropfung), MLP in ordinary nevi have not been systematically studied—so "pigment incontinence" may not apply to MLP in nevi. A total of 31 childhood nevi identified by pediatricians and family practitioners were evaluated for the distribution of MLP. We tested the hypothesis that a dermal origin of the melanin in MLP is more likely than dropping down from the epidermis. In our cohort, 90.3% (28/31) of childhood nevi had dermal MLP, a significantly higher frequency, compared to 31/60 ordinary adult nevi (P < 0.0001). Superficial dermis was the most common location (P < 0.001). However, only six specimens had MLP restricted to the superficial dermis, significantly less than predicted by the theory that melanin drops down from the epidermis (P < 0.00001). We also evaluated perivascular MLP, since nerves run together with vessels in neurovascular bundles (NVB), and it has been showed that precursors of melanocytes migrate from the neural crest to the skin as nerve sheath stem cells. Superficial NVB MLP correlated with deep NVB bundle MLP (P < 0.05), suggesting that NVB MLP represent "tombstones" for superficial and deep dermal nevus cells. Deep dermal, deep NVB, and deep periadnexal MLP may be valid biological criteria for diagnosis of congenital type (prenatal) nevi. Viewing prenatal nevi in children as a neurocristopathy fits a major principle of pediatric pathology: childhood diseases should be studied and understood based on what happens during tissue development. [ABSTRACT FROM AUTHOR]

In the last few years, the role of non-coding regulatory elements and their involvement in human disease have received great attention. Among the non-coding regulatory sequences, enhancers are particularly important for the proper establishment of cell type–specific gene-expression programs. Furthermore, the disruption of enhancers can lead to human disease through two main mechanisms: (i) Mutations or copy number variants can directly alter the enhancer sequences and thereby affect expression of their target genes; (ii) structural variants can provoke changes in 3-D chromatin organization that alter neither the enhancers nor their target genes, but rather the physical communication between them. In this review, these pathomechanisms are mostly discussed in the context of neurocristopathies, congenital disorders caused by defects that occur during neural crest development. We highlight why, due to its contribution to multiple tissues and organs, the neural crest represents an important, yet understudied, cell type involved in multiple congenital disorders. Moreover, we discuss currently available resources and experimental models for the study of human neurocristopathies. Last, we provide some practical guidelines that can be followed when investigating human neurocristopathies caused by structural variants. Importantly, these guidelines can be useful not only to uncover the etiology of human neurocristopathies, but also of other human congenital disorders in which enhancer disruption is involved. [ABSTRACT FROM AUTHOR]

Background: Craniofacial anomalies are among the most frequent birth defects worldwide, and are thought to be caused by gene‐environment interactions. Genetically manipulated zebrafish simulate human diseases and provide great advantages for investigating the etiology and pathology of craniofacial anomalies. Although substantial advances have been made in understanding genetic factors causing craniofacial disorders, limited information about the etiology by which environmental factors, such as teratogens, induce craniofacial anomalies is available in zebrafish. Results: Zebrafish embryos displayed craniofacial malformations after teratogen treatments. Further observations revealed characteristic disruption of chondrocyte number, shape and stacking. These findings suggested aberrant development of cranial neural crest (CNC) cells, which was confirmed by gene expression analysis of the CNC. Notably, these observations suggested conserved etiological pathways between zebrafish and mammals including human. Furthermore, several of these chemicals caused malformations of the eyes, otic vesicle, and/or heart, representing a phenocopy of neurocristopathy, and these chemicals altered the expression levels of the responsible genes. Conclusions: Our results demonstrate that chemical‐induced craniofacial malformation is caused by aberrant development of neural crest. This study indicates that zebrafish provide a platform for investigating contributions of environmental factors as causative agents of craniofacial anomalies and neurocristopathy. [ABSTRACT FROM AUTHOR]

The neural crest (NC), discovered by Wilhelm His 150 years ago, gives rise to a multipotent migratory embryonic cell population that generates a remarkably diverse and important array of cell types during the development of the vertebrate embryo. These cells originate in the neural plate border (NPB), which is the ectoderm between the neural plate and the epidermis. They give rise to the neurons and glia of the peripheral nervous system, melanocytes, chondrocytes, smooth muscle cells, odontoblasts and neuroendocrine cells, among others. Neurocristopathies are a class of congenital diseases resulting from the abnormal induction, specification, migration, differentiation or death of NC cells (NCCs) during embryonic development and have an important medical and societal impact. In general, congenital defects affect an appreciable percentage of newborns worldwide. Some of these defects are caused by teratogens, which are agents that negatively impact the formation of tissues and organs during development. In this review, we will discuss the teratogens linked to the development of many birth defects, with a strong focus on those that specifically affect the development of the NC, thereby producing neurocristopathies. Although increasing attention is being paid to the effect of teratogens on embryonic development in general, there is a strong need to critically evaluate the specific role of these agents in NC development. Therefore, increased understanding of the role of these factors in NC development will contribute to the planning of strategies aimed at the prevention and treatment of human neurocristopathies, whose etiology was previously not considered. [ABSTRACT FROM AUTHOR]

Fryns syndrome is an autosomal recessive multiple congenital anomaly/mental retardation syndrome characterized by coarse face, distal limb hypoplasia, and diaphragmatic anomalies. We describe a newborn girl with Fryns syndrome and Hirschsprung disease, an association that has been reported in five previous cases. These patients support the hypothesis that the neural crest plays a role in the pathogenesis of Fryns syndrome. Clinically asymptomatic or subtle anomalies that are in the spectrum of neural crest maldevelopment should be sought in all patients with Fryns syndrome including stillbirths, neonatal deaths, as well as long-term survivors. We suspect that the clinical observation about Hirschsprung disease and Fryns syndrome may provide insight into its molecular mechanisms and candidate genes.

Abstract Congenital hearing disorders affect millions of children worldwide and can significantly impact acquisition of speech and language. Efforts to identify the developmental genetic etiologies of conductive and sensorineural hearing losses have revealed critical roles for cranial neural crest cells (NCCs) in ear development. Cranial NCCs contribute to all portions of the ear, and defects in neural crest development can lead to neurocristopathies associated with profound hearing loss. The molecular mechanisms governing the development of neural crest derivatives within the ear are partially understood, but many questions remain. In this review, we describe recent advancements in determining neural crest contributions to the ear, how they inform our understanding of neurocristopathies, and highlight new avenues for further research using bioinformatic approaches. Highlights • The neural crest (NC) contributes to components of the outer, middle, and inner ear. • Disorders of NC development are frequently associated with hearing loss. • Understanding NC contributions to the ear will improve hearing restoration therapies. [ABSTRACT FROM AUTHOR]

Neural crest cells (NCCs) are a multipotent and migratory cell population in the developing embryo that contribute to the formation of a wide range of tissues. Defects in the development, differentiation and migration of NCCs give rise to a class of syndromes and diseases that are known as neurocristopathies. NCC development has historically been studied in a variety of animal models, including xenopus, chick and mouse. In the recent years, there have been efforts to study NCC development and disease in human specific models, with protocols being established to derive NCCs from human pluripotent stem cells (hPSCs), and to further differentiate these NCCs to neural, mesenchymal and other lineages. These in vitro differentiation platforms are a valuable tool to gain a better understanding of the molecular mechanisms involved in human neural crest development. The use of induced pluripotent stem cells (iPSCs) derived from patients afflicted with neurocristopathies has also enabled the study of defective human NCC development using these in vitro platforms. Here, we review the various in vitro strategies that have been used to derive NCCs from hPSCs and to specify NCCs into cranial, trunk, and vagal subpopulations and their derivatives. We will also discuss the potential applications of these human specific NCC platforms, including the use of iPSCs for disease modeling and the potential of NCCs for future regenerative applications.

Harlequin syndrome (HS) is a rare dysautonomia of the sympathetic nervous system leading to asymmetric facial flushing and sweating. In the literature, only a few cases of HS after thoracoscopic tracheoesophageal fistula (TEF) repair are reported. We report on a newborn with TEF who developed HS after thoracoscopic repair. On the first day of life, the girl (3,480 g, gestation age: 41 week) underwent thoracoscopic repair of a type C esophageal atresia (TEF; OR time 105 minute) without complications. The postoperative course was uneventful, the patient swallowed and thrived well and did not require esophageal dilatations. At 2 years of age, missing facial flushing, transpiration, and warming on the right side of her face during agitation were noticed. As no further intervention was required, the girl and her parents adapted well to the symptoms. Our report shows that the late onset of HS after the surgical procedure is unlikely a direct causal relation to the thoracoscopic operation but rather a shared embryological pathogenesis, like a neurocristopathy.

Neural crest cells (NCCs) are a multipotent and migratory cell population in the developing embryo that contribute to the formation of a wide range of tissues. Defects in the development, differentiation and migration of NCCs give rise to a class of syndromes and diseases that are known as neurocristopathies. NCC development has historically been studied in a variety of animal models, including xenopus, chick and mouse. In the recent years, there have been efforts to study NCC development and disease in human specific models, with protocols being established to derive NCCs from human pluripotent stem cells (hPSCs), and to further differentiate these NCCs to neural, mesenchymal and other lineages. These in vitro differentiation platforms are a valuable tool to gain a better understanding of the molecular mechanisms involved in human neural crest development. The use of induced pluripotent stem cells (iPSCs) derived from patients afflicted with neurocristopathies has also enabled the study of defective human NCC development using these in vitro platforms. Here, we review the various in vitro strategies that have been used to derive NCCs from hPSCs and to specify NCCs into cranial, trunk, and vagal subpopulations and their derivatives. We will also discuss the potential applications of these human specific NCC platforms, including the use of iPSCs for disease modeling and the potential of NCCs for future regenerative applications. [ABSTRACT FROM AUTHOR]

Congenital central hypoventilation syndrome (CCHS) is a disorder of ventilatory control and autonomic dysregulation that can be caused by mutations in the paired‐like homeobox 2B (PHOX2B) gene. The majority of CCHS cases are caused by polyalanine repeat mutations (PARMs) in PHOX2B; however, in rare cases, non‐polyalanine repeat mutations (NPARMs) have been identified. Here, we report two patients with NPARMs in PHOX2B. Patient 1 has a mild CCHS phenotype seen only on polysomnogram, which was performed for desaturations and stridor following a bronchiolitis episode, and characterized by night‐time hypoventilation and a history of ganglioneuroblastoma. She carried a novel de novo missense variant, p.R102S (c.304C > A), in exon 2. Patient 2 has an atypical CCHS phenotype including micrognathia, gastroesophageal reflux, stridor, hypopnea, and intermittent desaturations. Sleep study demonstrated that Patient 2 had daytime and night‐time hypercarbia with obstructive sleep apnea, requiring tracheostomy. On PHOX2B sequencing, she carried a recently identified nonsense variant, p.Y78* (c.234C > G), in exon 1. In summary, we present two patients with CCHS and identified NPARMs in PHOX2B who have distinct differences in phenotype severity, further elucidating the range of clinical outcomes in CCHS and illustrating the necessity of considering PHOX2B mutations when encountering atypical CCHS presentations. [ABSTRACT FROM AUTHOR]

A novel hypothesis proposes that “cardio-cephalic neural crest (NC) syndrome,” i.e. cephalic NC including cardiac NC, contributes to the concurrent occurrence of vascular diseases in the cardio- and cerebrovascular regions. NC is a transient structure present in early embryogenesis. Cephalic NC provides mesenchymal cells to the vascular media in these regions. Concurrent cardio- and cerebrovascular lesions have been reported in PHACE syndrome, ACTA2 mutation syndrome, and less frequently in the spontaneous occlusion of the circle of Willis (so-called moyamoya disease). Cardiovascular lesions in these syndromes include coarctation of the aorta, persistent truncus arteriosus, patent ductus arteriosus, and coronary artery disease, and cerebrovascular lesions include agenesis and stenosis/occlusion of the internal carotid arteries, and moyamoya phenomenon. These concurrent vascular lesions both in the cardio- and cerebrovascular regions might be related to cephalic NC. This hypothesis, although not proven, may facilitate a better understanding of the above-mentioned NC-related vascular pathologies and lead to appropriate diagnostic and therapeutic approaches for clinicians and chart future direction for researchers. [ABSTRACT FROM AUTHOR]

Waardenburg syndrome (WS) is a genetic disorder characterized by sensorineural hearing loss and pigmentation anomalies. The clinical definition of four WS types is based on additional features due to defects in structures mostly arising from the neural crest, with type I and type II being the most frequent. While type I is tightly associated to PAX3 mutations, WS type II (WS2) remains partly enigmatic with mutations in known genes ( MITF, SOX10) accounting for only 30% of the cases. We performed exome sequencing in a WS2 index case and identified a heterozygous missense variation in EDNRB. Interestingly, homozygous (and very rare heterozygous) EDNRB mutations are already described in type IV WS (i.e., in association with Hirschsprung disease [HD]) and heterozygous mutations in isolated HD. Screening of a WS2 cohort led to the identification of an overall of six heterozygous EDNRB variations. Clinical phenotypes, pedigrees and molecular segregation investigations unraveled a dominant mode of inheritance with incomplete penetrance. In parallel, cellular and functional studies showed that each of the mutations impairs the subcellular localization of the receptor or induces a defective downstream signaling pathway. Based on our results, we now estimate EDNRB mutations to be responsible for 5%-6% of WS2. [ABSTRACT FROM AUTHOR]

Anterior segment dysgeneses are developmental anomalies of the anterior eye segment that can occur as isolated defects or as part of various syndromes. A subgroup is caused by abnormal embryonic neural crest development. The Axenfeld-Rieger syndrome is an umbrella term for a continuum of anterior segment dysgeneses of neural crest origin, characterized by the presence of the Axenfeld or Rieger eye malformation predisposing for glaucoma. Additionally, other structures of neural crest origin can be variably affected giving rise to a wide spectrum of associated extra-ocular malformations. Key clinical features comprise facial dysmorphism including mid-face and dental hypoplasia, hearing loss, cardiac anomalies, and involuted periumbilical skin. The Axenfeld-Rieger syndrome is genetically heterogeneous and about 16% of cases are caused by heterozygous mutations inFOXC1at 6p25.3, a transcription factor gene regulating neural crest cell development. There is considerable clinical overlap between the Axenfeld-Rieger syndrome and the 6p25 deletion syndrome, a microdeletion syndrome characterized by heterozygous loss ofFOXC1. In both syndromes,FOXC1haploinsufficiency seems to be pathogenic. Here, we review the clinical features and pathogenesis of the 6p25 deletion syndrome. [ABSTRACT FROM AUTHOR]

Folate deficiency and hyperhomocysteinemia have long been associated with developmental anomalies, particularly neural tube defects and neurocristopathies-a group of diverse disorders that result from defective growth, differentiation, and migration of neural crest (NC) cells. However, the exact mechanisms by which homocysteine (Hcys) and/or folate deficiencies disrupt NC development are still poorly understood in mammals. In this work, we employed a well-defined culture system to investigate the effects of Hcys and folic acid (FA) supplementation on the morphogenetic processes of murine NC cells in vitro. We demonstrated that Hcys increases outgrowth and proliferation of cephalic NC cells and impairs their differentiation into smooth muscle cells. In addition, we showed that FA alone does not directly affect the developmental dynamics of the cephalic NC cells but is able to prevent the Hcys-induced effects. Our results, therefore, suggest that elevated Hcys levels per se cause dysmorphogenesis of the cephalic NC and might contribute to neurocristopathies in mammalian embryos. [ABSTRACT FROM AUTHOR]

Objectives: to define the prevalence and characteristics of associated congenital heart diseases in patients with Hirschsprung’s disease.Method: all patients with a histological diagnosis of Hirschsprung’s disease admitted to our hospital between January 2010 and December 2013 were included in this prospective observational study and underwent cardiovascular screening. Cardiac anatomy was assessed by a segmental echocardiographic approach. Measurements of aortic root and left ventricular dimensions, wall thickness and function were obtained. Congenital heart diseases requiring a percutaneous or surgical intervention were described as major hearts diseases.Results: 133 consecutive patients were enrolled at median age of 2.3 years. Eleven patients (8.3%) presented an associated heart disease. Moreover five patients had mild dilatation of aortic root. 6/11 (4.5%) patients had a major congenital heart diseases requiring surgical repair. Conclusions: prevalence of associated congenital heart diseases was slightly higher than in previous papers, and mostly represented by septal defects. 4/6 patients with major heart disease had also a chromosomal anomaly. If we do not consider the subpopulation of patients with a chromosomal anomaly, cardiac defects were present in 3.8% of the patients. Based on these results we suggest to perform routine echocardiogram in all Hirschsprung patients, with or without associated chromosomal syndromes.