CHARGE syndrome: a review

Ocular manifestations of CHARGE syndrome in a pediatric cohort with genotype/phenotype analysis

CHARGE syndrome is a rare multi-system condition associated with CHD7 variants. However, ocular manifestations and particularly ophthalmic genotype-phenotype associations, are not well-studied. This study evaluated ocular manifestations and genotype-phenotype associations in pediatric patients with CHARGE syndrome. A retrospective chart review included pediatric patients under 20 years-old with clinical diagnosis of CHARGE syndrome and documented ophthalmic examination. Demographics, genetic testing, and ocular findings were collected. Comprehensive literature review enhanced the genotype-phenotype analysis. Forty-two patients (20 male) underwent eye examination at an average age of 9.45 ± 6.52 years-old. Thirty-nine (93%) had ophthalmic manifestations in at least one eye. Optic nerve/chorioretinal colobomas were most common (38 patients), followed by microphthalmia (13), cataract (6), and iris colobomas (4). Extraocular findings included strabismus (32 patients), nasolacrimal duct obstructions (11, 5 with punctal agenesis), and cranial nerve VII palsy (10). Genotype-phenotype analyses (27 patients) showed variability in ocular phenotypes without association to location or variant types. Splicing (10 patients) and frameshift (10) variants were most prevalent. Patients with CHARGE syndrome may present with a myriad of ophthalmic manifestations. There is limited data regarding genotype-phenotype correlations and additional studies are needed.

Advance and Application of Single-cell Transcriptomics in Auditory Research

Hearing loss and deafness, as a worldwide disability disease, have been troubling human beings. However, the auditory organ of the inner ear is highly heterogeneous and has a very limited number of cells, which are largely uncharacterized in depth. Recently, with the development and utilization of single-cell RNA sequencing (scRNA-seq), researchers have been able to unveil the complex and sophisticated biological mechanisms of various types of cells in the auditory organ at the single-cell level and address the challenges of cellular heterogeneity that are not resolved through by conventional bulk RNA sequencing (bulk RNA-seq). Herein, we reviewed the application of scRNA-seq technology in auditory research, with the aim of providing a reference for the development of auditory organs, the pathogenesis of hearing loss, and regenerative therapy. Prospects about spatial transcriptomic scRNA-seq, single-cell based genome, and Live-seq technology will also be discussed.

Retinitis pigmentosa with iris coloboma due to miR-204 gene variant in a Chinese family

PURPOSE

To characterize the phenotype and genotype of a Chinese family with autosomal-dominant retinitis pigmentosa (RP) accompanied by iris coloboma.

METHODS

The proband, a 34-year-old male, was examined with his family by using fundus photography, optical coherence tomography (OCT), autofluorescence, and full-field electroretinography (ffERG). Genetic analyses were conducted through whole-exome sequencing (WES) to screen for variations.

RESULTS

Three members of this Chinese family were shown to be bilateral iris coloboma. The male proband and his mother exhibited typical RP feature. The proband's late grandfather had been documented manifestation of iris coloboma. The mode of inheritance was confirmed to be autosomal dominance. Through linkage analysis and WES, a heterozygous variation in the miR-204 gene (n.37C>T), a noncoding RNA gene, was identified in these three members.

CONCLUSIONS

In this third independent and the first Asian family, the existence of a miR-204 variant associated with RP accompanied by iris coloboma was confirmed. Our findings reinforce the significance of miR-204 as an important factor influencing visual function in the retina. When phenotypes like RP accompanied by iris coloboma in an autosomal-dominant pattern, including in Chinese patients, miR-204 aberrations should be considered.

CHARGE syndrome with both primary and secondary hypogonadism

Introduction

CHARGE syndrome is a rare disorder that causes congenital abnormalities in multiple organs, including secondary hypogonadism. We report, herein, a unique case of CHARGE syndrome with both primary and secondary hypogonadism and discuss the possible causes and pathogenesis in this patient.

Case presentation

A 15-year-old boy with delayed secondary sexual characteristics and non-palpable testes was referred to our hospital. Physical examination and detection of a chromodomain-helicase-deoxyribonucleic acid-binding protein 7 gene mutation confirmed CHARGE syndrome. Hormone stimulation tests suggested both primary and secondary hypogonadism. Laparoscopic bilateral orchiectomy was performed because of decreased testosterone production and atrophy in both testes. Pathological examination of the testes revealed maturation arrest, germ cell neoplasm in situ, and decreased expression of steroid synthase.

Conclusion

This appears to be the first report of CHARGE syndrome with both primary and secondary hypogonadism demonstrated in endocrinological and histological examinations.

The Incidence and Outcomes for Children with Cleft Palate and/or Lip and CHARGE Syndrome

OBJECTIVES

Published literature on children with cleft palate and/or lip (CP + /-L) and CHARGE syndrome (CS) is limited. This study investigated cleft characteristics including surgery, and feeding and communication outcomes in children identified with CP + /-L and CS.

DESIGN

Retrospective cross-sectional review.

SETTING

Regional Referral Centre for Paediatric Cleft Surgery.

PATIENTS

All children diagnosed with CP + /-L and CS (based on clinical features and/or CHD7 mutation testing) between 1989-2019.

MAIN OUTCOME MEASURES

Cleft type, timing of CP + /-L repair, reasons for 'delayed' repair, feeding methods and communication modality.

RESULTS

Twenty-two children with CP + /-L and CS were identified. Cleft sub-types (%) were: Eleven (50%) had bilateral cleft lip and palate (BCLP), six (27%) had unilateral cleft lip and palate (UCLP) and five (23%) had cleft palate (CP). Cleft repair was delayed compared to protocol care for non-syndromic children with CP + /-L. Median age for lip repair + /- vomerine flap was 9 months (range 4-22 months), and palate repair was 21 months (range 11-40 months). Median age for isolated CP repair was 13 months (range 7-23). Surgery for cardiac anomalies (36%) before cleft repair, and (59%) were classed as having severe systemic disease at the time of cleft surgery. Only 27% of the children in this study had both full oral feeding and verbal communication.

CONCLUSIONS

Children with CP + /-L and CS had severe cleft types and complex medical problems leading to delayed cleft surgery. Feeding and speech outcomes were better in the children aged over ten years.

A novel CHD7 variant in a chinese family with CHARGE syndrome

OBJECTIVE

CHARGE syndrome is a rare autosomal dominant (AD) multi-system disorder with a broad and variable clinical manifestation and occurs in approximately 1/10,000 newborns in the world. Mutations in the CHD7 gene are the genetic cause of over 90% of patients with typical CHARGE syndrome. The present study reported a novel variant in the CHD7 gene in a Chinese family with an abnormal fetus.

METHODS

Routine prenatal ultrasound screening showed fetal heart abnormality and left foot varus. Chromosomal microarray analysis (CMA) and fetus-parent whole-exome sequencing (trio-WES) were performed to determine the genetic cause of the fetus. The candidate variant was further verified using Sanger sequencing.

RESULTS

CMA analysis revealed normal results. However, WES analysis identified a de novo heterozygous variant of c.2919_2922del (NM_017780.4) on exon 11 of CHD7 gene, resulting in a premature truncation of the CHD7 protein (p.Gly975*). The variant was classified as Pathogenic (PVS1 + PS2_Moderate + PM2_Supporting) based on the ACMG guidelines. Combined with the clinical phenotype of fetal heart abnormalities, it was confirmed CHARGE syndrome.

CONCLUSION

We identified a novel heterozygous variant c.2919_2922del in CHD7 of a Chinese fetus with CHARGE syndrome, enriching the genotype-phenotype spectrum of CHD7. These results suggest that genetic testing could help facilitate prenatal diagnosis of CHARGE syndrome, thus promoting the appropriate genetic counseling.

Shared features in ear and kidney development - implications for oto-renal syndromes

The association between ear and kidney anomalies has long been recognized. However, little is known about the underlying mechanisms. In the last two decades, embryonic development of the inner ear and kidney has been studied extensively. Here, we describe the developmental pathways shared between both organs with particular emphasis on the genes that regulate signalling cross talk and the specification of progenitor cells and specialised cell types. We relate this to the clinical features of oto-renal syndromes and explore links to developmental mechanisms.

A guide to thymic selection of T cells

The thymus is an evolutionarily conserved organ that supports the development of T cells. Not only does the thymic environment support the rearrangement and expression of diverse T cell receptors but also provides a unique niche for the selection of appropriate T cell clones. Thymic selection ensures that the repertoire of available T cells is both useful (being MHC-restricted) and safe (being self-tolerant). The unique antigen-presentation features of the thymus ensure that the display of self-antigens is optimal to induce tolerance to all types of self-tissue. MHC class-specific functions of CD4+ T helper cells, CD8+ killer T cells and CD4+ regulatory T cells are also established in the thymus. Finally, the thymus provides signals for the development of several minor T cell subsets that promote immune and tissue homeostasis. This Review provides an introductory-level overview of our current understanding of the sophisticated thymic selection mechanisms that ensure T cells are useful and safe.

Digenic CHD7 and SMCHD1 inheritance Unveils phenotypic variability in a family mainly presenting with hypogonadotropic hypogonadism

Objectives

CHARGE syndrome is a congenital hereditary condition involving multiple systems. Patients are easily misdiagnosed with idiopathic hypogonadotropic hypogonadism (IHH) due to the overlap of clinical manifestations. An accurate clinical diagnosis remains challenging when the predominant clinical manifestation resembles hypogonadotropic hypogonadism.

Methods

This original research is conducted based on the genetic finding and analysis of clinical cases. Whole-exome sequencing (WES) and in-silico analyse were performed on two sisters to investigate the pathogenesis in this family. Homology modelling was conducted to evaluate structural changes in the variants.

Results

WES and Sanger sequencing revealed two siblings carrying a nonsense mutation (NM_017780.4: c.115C > T) in exon 2 of CHD7 inherited from a mildly affected mother and a missense mutation (NM_015295.3: c.2582T > C) in exon 20 of SMCHD1 inherited from an asymptomatic father. The nonsense mutation in CHD7 was predicted to generate nonsense-mediated decay, whereas the missense mutation in SMCHD1 decreased protein stability.

Conclusions

We identified digenic CHD7 and SMCHD1 mutations in IHH-associated diseases for the first time and verified the synergistic role of oligogenic inheritance. It was also determined that WES is an effective tool for distinguishing diseases with overlapping features and establishing a molecular diagnosis for cases with digenic or oligogenic hereditary disorders, which is beneficial for timely treatment, and family genetic counseling.

Prenatal diagnosis of fetal digestive system malformations and pregnancy outcomes at a tertiary referral center in Fujian, China: A retrospective study

Fetal digestive system malformations (DSMs) are correlated with chromosomal anomalies. The prenatal diagnosis of DSMs allows for timely treatment and reduces perinatal morbidity and mortality. However, genetic screening for fetal DSMs is rarely reported. This study aimed to investigate genetic etiology and pregnancy outcomes in cases of fetal DSM by analyzing correlations between DSM types and chromosomal anomalies. This retrospective single-center study included 126 fetuses in whom DSMs were detected via prenatal ultrasonography. Genetic etiology was investigated using conventional karyotyping, chromosome microarray analysis (CMA), and whole-exome sequencing (WES). DSMs were categorized as simple DSM (Group A), DSM combined with abnormal ultrasound soft markers (Group B), and DSM combined with comorbidities of other systems (Group C). Abnormal karyotypes were detected in 11/126 (8.7 %) fetuses. Four more pathogenic copy number variants (CNVs) were detected using CMA, increasing the detection rate to 11.9 %. The detection rates significantly differed between the three DSM types (1.78 %, 8.11 %, and 33.33 % in Groups A, B, and C, respectively). The overall adverse pregnancy outcome rate was 33.9 %, and 11.5 %, 23.5 %, and 81.3 %, (P < 0.001), respectively, in Groups A, B, and C. Out of 83 live births, three neonates died, 26 underwent postnatal surgery with 24 favorable outcomes, and 54 did not undergo surgery and were basically normal. Two neonates who underwent WES were diagnosed with CHD7-associated Charge syndrome and JAG1-associated Alagille syndrome, respectively. Our findings demonstrate that fetal DSM is closely related to chromosome aneuploidies, CNVs, and point mutations. The prognoses of most fetuses with simple DSM and those with comorbid abnormal ultrasound soft markers were favorable in the absence of chromosomal anomalies and severe structural malformations, provided they underwent timely surgery as neonates. These findings provide guidance for the prenatal diagnosis and clinical management of fetal DSMs and the genetic counseling of parents.

Inherited causes of combined vision and hearing loss: clinical features and molecular genetics

Combined vision and hearing loss, also known as dual sensory impairment, can occur in several genetic conditions, including ciliopathies such as Usher and Bardet-Biedl syndrome, mitochondrial DNA disorders and systemic diseases, such as CHARGE, Stickler, Waardenburg, Alport and Alstrom syndrome. The retinal phenotype may point to the diagnosis of such disorders. Herein, we aim to provide a comprehensive review of the molecular genetics and clinical features of the most common non-chromosomal inherited disorders to cause dual sensory impairment.

Overlapping pathogenic de novo CNVs in neurodevelopmental disorders and congenital anomalies impacting constraint genes regulating early development

Neurodevelopmental disorders (NDDs) and congenital anomalies (CAs) are rare disorders with complex etiology. In this study, we investigated the less understood genomic overlap of copy number variants (CNVs) in two large cohorts of NDD and CA patients to identify de novo CNVs and candidate genes associated with both phenotypes. We analyzed clinical microarray CNV data from 10,620 NDD and 3176 CA cases annotated using Horizon platform of GenomeArc Analytics and applied rigorous downstream analysis to evaluate overlapping genes from NDD and CA CNVs. Out of 13,796 patients, only 195 cases contained 218 validated de novo CNVs. Eighteen percent (31/170) de novo CNVs in NDD cases and 40% (19/48) de novo CNVs in CA cases contained genomic overlaps impacting developmentally constraint genes. Seventy-nine constraint genes (10.1% non-OMIM entries) were found to have significantly enriched genomic overlap within rare de novo pathogenic deletions (P value = 0.01, OR = 1.58) and 45 constraint genes (13.3% non-OMIM entries) within rare de novo pathogenic duplications (P value = 0.01, OR = 1.97). Analysis of spatiotemporal transcriptome demonstrated both pathogenic deletion and duplication genes to be highly expressed during the prenatal stage in human developmental brain (P value = 4.95 X 10-6). From the list of overlapping genes, EHMT1, an interesting known NDD gene encompassed pathogenic deletion CNVs from both NDD and CA patients, whereas FAM189A1, and FSTL5 are new candidate genes from non-OMIM entries. In summary, we have identified constraint overlapping genes from CNVs (including de novo) in NDD and CA patients that have the potential to play a vital role in common disease etiology.

Pervasive cortical and white matter anomalies in a mouse model for CHARGE syndrome

CHARGE (Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth, Genital anomalies and Ear abnormalities) syndrome is a disorder caused by mutations in the gene encoding CHD7, an ATP dependent chromatin remodelling factor, and is characterised by a diverse array of congenital anomalies. These include a range of neuroanatomical comorbidities which likely underlie the varied neurodevelopmental disorders associated with CHARGE syndrome, which include intellectual disability, motor coordination deficits, executive dysfunction, and autism spectrum disorder. Cranial imaging studies are challenging in CHARGE syndrome patients, but high-throughput magnetic resonance imaging (MRI) techniques in mouse models allow for the unbiased identification of neuroanatomical defects. Here, we present a comprehensive neuroanatomical survey of a Chd7 haploinsufficient mouse model of CHARGE syndrome. Our study uncovered widespread brain hypoplasia and reductions in white matter volume across the brain. The severity of hypoplasia appeared more pronounced in posterior areas of the neocortex compared to anterior regions. We also perform the first assessment of white matter tract integrity in this model through diffusion tensor imaging (DTI) to assess the potential functional consequences of widespread reductions in myelin, which suggested the presence of white matter integrity defects. To determine if white matter alterations correspond to cellular changes, we quantified oligodendrocyte lineage cells in the postnatal corpus callosum, uncovering reduced numbers of mature oligodendrocytes. Together, these results present a range of promising avenues of focus for future cranial imaging studies in CHARGE syndrome patients.

Generalized keratosis pilaris induced by testosterone injections in a patient with CHARGE syndrome

Keratosis pilaris (KP) is a common disorder of follicular keratinization characterized by keratotic follicular papules with varying degrees of perifollicular erythema. Keratosis pilaris affects up to half of normal children and up to three-quarters of children with atopic dermatitis. KP is prominent during adolescence and less common in older people, but it may occur in children and adults of all ages. In this report, we describe the case of a 13-year-old boy known to have CHARGE syndrome who developed generalized keratosis pilaris after testosterone injections. To the best of our knowledge, this is the first reported case of generalized keratosis pilaris induced by testosterone injection.

Chromosome 22q11.2 Deletion Syndrome: A Comprehensive Review of Molecular Genetics in the Context of Multidisciplinary Clinical Approach

The 22q11.2 deletion syndrome is a multisystemic disorder characterized by a marked variability of phenotypic features, making the diagnosis challenging for clinicians. The wide spectrum of clinical manifestations includes congenital heart defects-most frequently conotruncal cardiac anomalies-thymic hypoplasia and predominating cellular immune deficiency, laryngeal developmental defects, midline anomalies with cleft palate and velar insufficiency, structural airway defects, facial dysmorphism, parathyroid and thyroid gland hormonal dysfunctions, speech delay, developmental delay, and neurocognitive and psychiatric disorders. Significant progress has been made in understanding the complex molecular genetic etiology of 22q11.2 deletion syndrome underpinning the heterogeneity of clinical manifestations. The deletion is caused by chromosomal rearrangements in meiosis and is mediated by non-allelic homologous recombination events between low copy repeats or segmental duplications in the 22q11.2 region. A range of genetic modifiers and environmental factors, as well as the impact of hemizygosity on the remaining allele, contribute to the intricate genotype-phenotype relationships. This comprehensive review has been aimed at highlighting the molecular genetic background of 22q11.2 deletion syndrome in correlation with a clinical multidisciplinary approach.

Impact of Genetic Disorders in the Surgical Management of Congenital Heart Disease

The congenital heart surgeon frequently encounters patients with various genetic disorders requiring surgical intervention. Although the specifics of the genetics for these patients and their families lie in the purview of specialists in genetics, the surgeon is well-served to be familiar with aspects of specific syndromes that impact surgical management and perioperative care. This aids in counseling families in expectations for the hospital course and recovery as well as can impact intraoperative and surgical management. This review article summarizes key characteristics for the congenital heart surgeon to be familiar with for common genetic disorders as they help coordinate care.

Predicting the clinical trajectory of feeding and swallowing abilities in CHARGE syndrome

To date, the feeding and oral-motor abilities of patients with CHARGE syndrome (CS) have not been longitudinally assessed. This study aims to investigate the level of these abilities at different ages and evaluate how they evolve during growth. We retrospectively analysed oral-motor features of 16 patients with molecularly confirmed CS (age range 4-21 years old; mean 11 years; SD 6 years; median 10 years). Nearly 100% of CS new-borns had weak sucking at birth, and half of them demonstrated poor coordination between breathing and swallowing. Over time, the percentages of children with tube feeding dependence (60% at birth) faced a slow but steady decrease (from 33% at 6 months, 25% at 12 months, to 13% at school age) in tandem with the decreasing risk of aspiration. The ability of eating foods requiring chewing was achieved at school age, after the acquisition of an adequate oral sensory processing. A mature chewing pattern with a variety of food textures was not achieved by more than half of patients, including those requiring artificial enteral nutrition. Most patients started prolonged oral-motor treatments with speech language therapists in early childhood.

CONCLUSIONS

Although feeding and swallowing disorders are constant features in CS patients, a slow and gradual development of feeding abilities occurs in most cases. Rehabilitation plays a key role in overcoming structural and functional difficulties and attaining appropriate eating skills.

WHAT IS KNOWN

• Feeding problems and swallowing dysfunction have been noted in CHARGE syndrome. • The involvement of multiple factors, including structural problems in the mouth, throat, or esophagus, and neurological impairment, make feeding a complicated task in CHARGE individuals.

WHAT IS NEW

• Dysphagia gradually improves in most CHARGE children over time, though with a wide interindividual variability. • The percentages of children with tube feeding dependence decrease over time from 60% at birth to 33% at 6 months and 13% at school age.

Chromatin remodeler Chd7 regulates photoreceptor development and outer segment length

Mutations in the chromatin remodeling factor CHD7 are the predominant cause of CHARGE syndrome, a congenital disorder that frequently includes ocular coloboma. Although CHD7 is known to be required for proper ocular morphogenesis, its role in retinal development has not been thoroughly investigated. Given that individuals with CHARGE syndrome can experience visual impairment even in the absence of coloboma, a better understanding of CHD7 function in the retina is needed. In this study, we characterized the expression pattern of Chd7 in the developing zebrafish and mouse retina and documented ocular and retinal phenotypes in Chd7 loss-of-function mutants. Zebrafish Chd7 was expressed throughout the retinal neuroepithelium when retinal progenitor cells were actively proliferating, and later in subsets of newly post-mitotic retinal cells. At stages of retinal development when most retinal cell types had terminally differentiated, Chd7 expression remained strong in the ganglion cell layer and in some cells in the inner nuclear layer. Intriguingly, strong expression of Chd7 was also observed in the outer nuclear layer where it was co-expressed with markers of post-mitotic cone and rod photoreceptors. Expression of mouse CHD7 displayed a similar pattern, including expression in the ganglion cells, subsets of inner nuclear layer cells, and in the distal outer nuclear layer as late as P15. Two different mutant chd7 zebrafish lines were characterized for ocular and retinal defects. These mutants displayed microphthalmia, reduced numbers of cone photoreceptors, and truncated rod and cone photoreceptor outer segments. Reduced cone photoreceptor number and abnormal outer segments were also observed in heterozygous Chd7 mutant mice. Taken together, our results in zebrafish and mouse reveal a conserved, previously undescribed role for Chd7 in retinal development and photoreceptor outer segment morphogenesis. Moreover, our work suggests an avenue of future investigation into the pathogenesis of visual system defects in CHARGE syndrome.

Craniofacial and cardiac defects in chd7 zebrafish mutants mimic CHARGE syndrome

Congenital heart defects occur in almost 80% of patients with CHARGE syndrome, a sporadically occurring disease causing craniofacial and other abnormalities due to mutations in the CHD7 gene. Animal models have been generated to mimic CHARGE syndrome; however, heart defects are not extensively described in zebrafish disease models of CHARGE using morpholino injections or genetic mutants. Here, we describe the co-occurrence of craniofacial abnormalities and heart defects in zebrafish chd7 mutants. These mutant phenotypes are enhanced in the maternal zygotic mutant background. In the chd7 mutant fish, we found shortened craniofacial cartilages and extra cartilage formation. Furthermore, the length of the ventral aorta is altered in chd7 mutants. Many CHARGE patients have aortic arch anomalies. It should be noted that the aberrant branching of the first branchial arch artery is observed for the first time in chd7 fish mutants. To understand the cellular mechanism of CHARGE syndrome, neural crest cells (NCCs), that contribute to craniofacial and cardiovascular tissues, are examined using sox10:Cre lineage tracing. In contrast to its function in cranial NCCs, we found that the cardiac NCC-derived mural cells along the ventral aorta and aortic arch arteries are not affected in chd7 mutant fish. The chd7 fish mutants we generated recapitulate some of the craniofacial and cardiovascular phenotypes found in CHARGE patients and can be used to further determine the roles of CHD7.

Task force Guideline of Brazilian Society of Otology ‒ hearing loss in children - Part I ‒ Evaluation

OBJECTIVES

To provide an overview of the main evidence-based recommendations for the diagnosis of hearing loss in children and adolescents aged 0 to 18 years.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on childhood hearing loss were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The evaluation and diagnosis of hearing loss: universal newborn hearing screening, laboratory testing, congenital infections (especially cytomegalovirus), genetic testing and main syndromes, radiologic imaging studies, vestibular assessment of children with hearing loss, auditory neuropathy spectrum disorder, autism spectrum disorder, and noise-induced hearing loss.

CONCLUSIONS

Every child with suspected hearing loss has the right to diagnosis and appropriate treatment if necessary. This task force considers 5 essential rights: (1) Otolaryngologist consultation; (2) Speech assessment and therapy; (3) Diagnostic tests; (4) Treatment; (5) Ophthalmologist consultation.

CHD7 regulates otic lineage specification and hair cell differentiation in human inner ear organoids

Mutations in CHD7 cause CHARGE syndrome, affecting multiple organs including the inner ear in humans. We investigate how CHD7 mutations affect inner ear development using human pluripotent stem cell-derived organoids as a model system. We find that loss of CHD7 or its chromatin remodeling activity leads to complete absence of hair cells and supporting cells, which can be explained by dysregulation of key otic development-associated genes in mutant otic progenitors. Further analysis of the mutant otic progenitors suggests that CHD7 can regulate otic genes through a chromatin remodeling-independent mechanism. Results from transcriptome profiling of hair cells reveal disruption of deafness gene expression as a potential underlying mechanism of CHARGE-associated sensorineural hearing loss. Notably, co-differentiating CHD7 knockout and wild-type cells in chimeric organoids partially rescues mutant phenotypes by restoring otherwise severely dysregulated otic genes. Taken together, our results suggest that CHD7 plays a critical role in regulating human otic lineage specification and hair cell differentiation.

Zfp503/Nlz2 Is Required for RPE Differentiation and Optic Fissure Closure

Purpose

Uveal coloboma is a congenital eye malformation caused by failure of the optic fissure to close in early human development. Despite significant progress in identifying genes whose regulation is important for executing this closure, mutations are detected in a minority of cases using known gene panels, implying additional genetic complexity. We have previously shown knockdown of znf503 (the ortholog of mouse Zfp503) in zebrafish causes coloboma. Here we characterize Zfp503 knockout (KO) mice and evaluate transcriptomic profiling of mutant versus wild-type (WT) retinal pigment epithelium (RPE)/choroid.

Methods

Zfp503 KO mice were generated by gene targeting using homologous recombination. Embryos were characterized grossly and histologically. Patterns and level of developmentally relevant proteins/genes were examined with immunostaining/in situ hybridization. The transcriptomic profile of E11.5 KO RPE/choroid was compared to that of WT.

Results

Zfp503 is dynamically expressed in developing mouse eyes, and loss of its expression results in uveal coloboma. KO embryos exhibit altered mRNA levels and expression patterns of several key transcription factors involved in eye development, including Otx2, Mitf, Pax6, Pax2, Vax1, and Vax2, resulting in a failure to maintain the presumptive RPE, as evidenced by reduced melanin pigmentation and its differentiation into a neural retina-like lineage. Comparison of RNA sequencing data from WT and KO E11.5 embryos demonstrated reduced expression of melanin-related genes and significant overlap with genes known to be dynamically regulated at the optic fissure.

Conclusions

These results demonstrate a critical role of Zfp503 in maintaining RPE fate and optic fissure closure.

Hypogonadism in Males With Genetic Neurodevelopmental Syndromes

Genetic syndromes that affect the nervous system may also disrupt testicular function, and the mechanisms for these effects may be interrelated. Most often neurological signs and symptoms predominate and hypogonadism remains undetected and untreated, while in other cases, a thorough evaluation of a hypogonadal male reveals previously unrecognized ataxia, movement disorder, muscle weakness, tremor, or seizures, leading to a syndromic diagnosis. Androgen deficiency in patients with neurological diseases may aggravate muscle weakness and fatigue and predispose patients to osteoporosis and obesity. The purpose of this mini review is to provide a current understanding of the clinical, biochemical, histologic, and genetic features of syndromes in which male hypogonadism and neurological dysfunction may coexist and may be encountered by the clinical endocrinologist.

Eyes on CHARGE syndrome: Roles of CHD7 in ocular development

The development of the vertebrate visual system involves complex morphogenetic interactions of cells derived from multiple embryonic lineages. Disruptions in this process are associated with structural birth defects such as microphthalmia, anophthalmia, and coloboma (collectively referred to as MAC), and inherited retinal degenerative diseases such as retinitis pigmentosa and allied dystrophies. MAC and retinal degeneration are also observed in systemic congenital malformation syndromes. One important example is CHARGE syndrome, a genetic disorder characterized by coloboma, heart defects, choanal atresia, growth retardation, genital abnormalities, and ear abnormalities. Mutations in the gene encoding Chromodomain helicase DNA binding protein 7 (CHD7) cause the majority of CHARGE syndrome cases. However, the pathogenetic mechanisms that connect loss of CHD7 to the ocular complications observed in CHARGE syndrome have not been identified. In this review, we provide a general overview of ocular development and congenital disorders affecting the eye. This is followed by a comprehensive description of CHARGE syndrome, including discussion of the spectrum of ocular defects that have been described in this disorder. In addition, we discuss the current knowledge of CHD7 function and focus on its contributions to the development of ocular structures. Finally, we discuss outstanding gaps in our knowledge of the role of CHD7 in eye formation, and propose avenues of investigation to further our understanding of how CHD7 activity regulates ocular and retinal development.

Phenotypic characteristics and variability in CHARGE syndrome: a PRISMA compliant systematic review and meta-analysis

BACKGROUND

CHARGE syndrome (OMIM #214800) is a phenotypically complex genetic condition characterised by multi-system, multi-sensory impairments. Behavioural, psychological, cognitive and sleep difficulties are not well delineated and are likely associated with biopsychosocial factors.

METHODS

This meta-analysis investigated the prevalence of clinical features, physical characteristics and conditions, behavioural, psychological, cognitive and sleep characteristics in CHARGE syndrome, and statistically evaluated directional associations between these characteristics. Pooled prevalence estimates were calculated using reliable, prespecified quality weighting criteria, and meta-regression was conducted to identify associations between characteristics.

RESULTS

Of the 42 eligible studies, data could be extracted for 1675 participants. Prevalence estimates were highest for developmental delay (84%), intellectual disability (64%), aggressive behaviour (48%), self-injurious behaviour (44%) and sleep difficulties (45%). Meta-regression indicated significant associations between intellectual disability and choanal atresia, intellectual disability and inner ear anomalies, sleep difficulties and growth deficiency, and sleep difficulties and gross motor difficulties.

CONCLUSIONS

Our comprehensive review of clinical features, behavioural, psychological, cognitive and physical characteristics, conditions and comorbidities in CHARGE syndrome provides an empirically based foundation to further research and practice.

CHARGE syndrome presenting with persistent hypoglycemia: case report and overview of the main genetic syndromes associated with neonatal hypoglycemia

Background

CHARGE syndrome (CS) is an autosomal dominant genetic condition whose recognition in the neonatal period is complicated by considerable phenotypic variability. Pediatric patients with genetic disorders have a known high incidence of hypoglycemia, due to many concurring factors. To date, neonatal hypoglycemia is a feature poorly explored in the literature associated with CS. This paper adds to the existing literature on hypoglycemia in CS and provides a brief review of the mechanisms through which CS, as well as the main genetic syndromes associated with neonatal hypoglycemia, may determine it.

Case presentation

The patient was a term newborn, first-born daughter to non-consanguineous parents. At birth, axial hypotonia with slight hypertonia of the limbs, and dysplastic auricles were noted. The incidental finding of asymptomatic hypoglycemia led to the initiation of glucose infusion on the II day of life, continued for a total of 8 days (maximum infusion rate: 8 mg/kg/min). In-depth endocrinological examinations showed poor cortisol response to the hypoglycemic stimulus, with normal GH values, thyroid function and ACTH. In view of the suspected hypoadrenalism, oral hydrocortisone therapy was initiated. Inappropriately low values of plasmatic and urinary ketones supported the hypothesis of concomitant transient hyperinsulinism, not requiring therapy. A brain MRI was performed, documenting thinning of the optic nerves, non-displayable olfactory bulbs and dysmorphic corpus callosum. An eye examination revealed bilateral chorioretinal coloboma. Temporal bone CT scan showed absence of the semicircular canals. The unexpected findings of coloboma and absence of semicircular canals led to the suspicion of CS, later confirmed by the molecular analysis of CHD7.

Conclusions

It seems important to consider CS in the differential diagnosis of persistent hypoglycemia in newborns with specific anomalies. At the same time, it is advisable to consider the risk of hypoglycemia in children with CS, as well as other genetic syndromes. Awareness of the many possible causes of hypoglycemia in newborns with genetic conditions may help steer the investigations, allowing for an appropriate and timely treatment.

A case of Gross E esophageal atresia discovered following a unique clinical course

The patient was a 15 months-old boy who had been diagnosed CHARGE syndrome, which is a multiple congenital anomaly syndrome caused by mutations in the CHD7 gene. Mechanical ventilation management was initiated 2 hours after birth for dysphagia and respiratory failure, and tracheotomy was performed 3 months after birth for dysphagia and failed extubation. He was repeatedly hospitalized due to pneuomoniae. Approximately 1 year after birth, the boy had two consecutive episodes of sudden ventilatory insufficiency while replacing the tracheotomy cannula. A bronchoscopic examination under general anesthesia revealed a tracheoesophageal fistula directly below the tracheostomy. The patient was diagnosed with Gross E esophageal atresia, and we speculated that the cannula migrated to the esophagus via the fistula during tracheostomy cannula replacement. Gross E esophageal atresia is a rare disease. Its diagnosis is often delayed, and it is discovered by recurrent pneumonia in many cases. A tracheoesophageal fistula may also be found in children with deformities of the respiratory system. Furthermore, tracheoesophageal fistulae are often found in the neck. Therefore, when sudden ventilatory insufficiency occurs in a child with a tracheostomy after replacing the tracheostomy cannula, caution must be exercised since the cannula may have migrated to the esophagus via a fistula. J. Med. Invest. 69 : 141-144, February, 2022.

Fetal central nervous system anomalies: When should we offer exome sequencing?

OBJECTIVE

To investigate the detection of pathogenic variants using exome sequencing in an international cohort of fetuses with central nervous system (CNS) anomalies.

METHODS

We reviewed trio exome sequencing (ES) results for two previously reported unselected cohorts (Prenatal Assessment of Genomes and Exomes (PAGE) and CUIMC) to identify fetuses with CNS anomalies with unremarkable karyotypes and chromosomal microarrays. Variants were classified according to ACMG guidelines and association of pathogenic variants with specific types of CNS anomalies explored.

RESULTS

ES was performed in 268 pregnancies with a CNS anomaly identified using prenatal ultrasound . Of those with an isolated, single, CNS anomaly, 7/97 (7.2%) had a likely pathogenic/pathogenic (LP/P) variant. This includes 3/23 (13%) fetuses with isolated mild ventriculomegaly and 3/10 (30%) fetuses with isolated agenesis of the corpus callosum. Where there were multiple anomalies within the CNS, 12/63 (19%) had LP/P variants. Of the 108 cases with CNS and other organ system anomalies, 18 (16.7%) had LP/P findings.

CONCLUSION

ES is an important tool in the prenatal evaluation of fetuses with any CNS anomaly. The rate of LP/P variants tends to be highest in fetuses with multiple CNS anomalies and multisystem anomalies, however, ES may also be of benefit for isolated CNS anomalies.

Clinical and molecular delineation of mandibulofacial dysostosis with microcephaly in six Korean patients: When to consider EFTUD2 analysis?

Mandibulofacial dysostosis with microcephaly (MFDM, OMIM#610536) is an extremely rare genetic syndrome characterised by microcephaly, external ear deformity, hearing loss, and distinct facial appearance, including zygomatic hypoplasia and micrognathia. Occasionally, various malformations in other internal organs, including oesophageal atresia or tracheoesophageal fistula, may lead to life-threatening situations. Haploinsufficiency of EFTUD2 is responsible for MFDM. Here, we present the phenotypic and genetic characteristics of six Korean children who were diagnosed with MFDM by molecular genetic testing. All but one patient had occipitofrontal circumferences below the -2.0 standard deviation score. Micrognathia was identified in all patients. A cleft palate (66.7%) and other facial dysmorphisms, including facial asymmetry (50%) and malar hypoplasia (50%), were also frequently observed. Hearing loss was observed in all patients along with one or more internal and external ear deformities, including ossicular anomalies, auditory canal stenosis, and microtia. Two patients (33.3%) had undergone surgery for tracheoesophageal fistula type C. Most patients were initially misdiagnosed as other better-known syndromes with overlapping characteristics, such as Treacher Collins or CHARGE syndrome. The first three patients were diagnosed using exome sequencing. However, after increased awareness of MFDM in the first three patients, MFDM was considered one of the initial differential diagnoses and could be diagnosed by target gene analysis in the remaining three cases. Thus, we recommend targeted EFTUD2 analysis as the initial workup for the rapid diagnosis of MFDM in patients with facial dysostosis, microcephaly, and otologic problems.

Facial Asymmetry: A Narrative Review of the Most Common Neurological Causes

Symmetry of the face is one of the most important features for the perception of attractiveness. Asymmetry of the face means that the right and left sides of the face are not identical. Subclinical facial asymmetry is very common in the general population. Most people have some slight facial asymmetry, and this is the normal biological situation in humans. Abnormalities from soft tissue, dental, and skeletal elements lead to facial asymmetry. Asymmetry has many causal factors, and its aetiology includes both congenital and acquired conditions. Neurological facial asymmetry is scarcely addressed in the dental literature. In this narrative review, we focus on the most common neurological causes of facial asymmetry. From a neurological point of view, facial asymmetry can result from disturbances of the cranial nerves, developmental disorders, or myopathies. In the broad range of differential diagnostics of facial asymmetry, neurological abnormalities should be taken into consideration. The treatment must be related to the underlying cause. Complete knowledge of the aetiological factors and the character of the asymmetry plays a crucial role in formulating a treatment plan.

Anophthalmia and microphthalmia in children: associated ocular, somatic and genetic morbidities and quality of life

PURPOSE

To report ocular outcome, somatic co-morbidities, genetics, and quality of life in children born with anophthalmia (A) or microphthalmia (M).

METHODS

Thirty-five children (19 boys) with A/M underwent ophthalmological examinations and a review of medical records. Parents of 12/22 cases completed the Pediatric Quality of Life Inventory (PedsQL).

RESULTS

Age at examination ranged from 7 months to 18 years (median 2.3 years). Ten cases were totally blind or had light perception. Isolated A/M occurred in 16/35 cases, while somatic, psychomotor, neuroradiological and/or genetic pathology occurred in 19/35 cases both in the bilateral (7/9) and in the unilateral group (12/26). Among 26 unilateral cases, 4/16 with one normal eye had associated problems compared to 9/10 if the contralateral eye was pathological (p < .01). There was an increased risk for heart defects in children with psychomotor delay (p = .04). Pathogenic genetic abnormalities were identified in 10/24 cases. Neuroimaging demonstrated pathology in 14/20 cases with corpus callosum dysgenesis (6/20) being the most common. The median total PedsQL score of parent reports for ages 2-12 was 52.4 (range 22.6-100).

CONCLUSIONS

Somatic, psychomotor and/or neuroradiological pathologies were more common in bila-teral than unilateral cases, but the difference was not significant. There was decreased risk in unilateral cases with one normal eye. Genetic defects occurred in both unilateral and bilateral cases. Health-related quality of life was reduced.

[CHARGE syndrome in children with congenital choanal atresia]

One of the most commonly associated genetic syndromes with congenital choanal atresia is CHARGE syndrome, which includes multiple congenital anomalies with variable phenotypic manifestations. The article presents data on the history of the study, prevalence, etiology and clinical criteria of this pathology.

OBJECTIVE

To determine the frequency of detection and features of clinical manifestations of CHARGE syndrome in children with congenital choanal atresia.

MATERIAL AND METHODS

Based on the literature data and our own research, the features of the clinical manifestations of CHARGE syndrome in children with congenital choanal atresia are presented.

RESULTS

The association of malformations, which in most cases had bilateral localization, was detected in 27 (18.8%) patients with congenital choanal atresia. In 20 children, the analysis for the presence of the CHD7 mutation was carried out by sequencing, while CHD7 mutations were detected in 18 (90%) patients meeting the clinical criteria of CHARGE syndrome. The absence of mutations of the CHD7 gene in the remaining patients indicates the genetic heterogeneity of this syndrome.

CONCLUSION

The detection of CHARGE syndrome in children with congenital choanal atresia is of great clinical importance, since timely diagnosis and correction of other pathology minimizes the chance of complications during surgical treatment and allows for the formation of individual routing of patients for treatment and rehabilitation. Therefore, the examination and management of children with congenital choanal atresia associated with other malformations should be carried out on the basis of an interdisciplinary approach.

Pediatrics for Disability: A Comprehensive Approach to Children with Syndromic Psychomotor Delay

Intellectual disability is the impairment of cognitive, linguistic, motor and social skills that occurs in the pediatric age and is also described by the term "mental retardation". Intellectual disability occurs in 3-28 % of the general population due to a genetic cause, including chromosome aberrations. Among people with intellectual disabilities, the cause of the disability was identified as a single gene disorder in up to 12 %, multifactorial disorders in up to 4 %, and genetic disorders in up to 8.5 %. Children affected by a malformation syndrome associated with mental retardation or intellectual disability represent a care challenge for the pediatrician. A multidisciplinary team is essential to manage the patient, thereby controlling the complications of the syndrome and promoting the correct psychophysical development. This requires continuous follow-up of these children by the pediatrician, which is essential for both the clinical management of the syndrome and facilitating the social integration of these children.

Rare Genetic Syndromes and Oral Anomalies: A Review of the Literature and Case Series with a New Classification Proposal

Rare genetic syndromes, conditions with a global average prevalence of 40 cases/100,000 people, are associated with anatomical, physiological, and neurological anomalies that may affect different body districts, including the oral district. So far, no classification of oral abnormalities in rare genetic syndromes is present in the literature. The aim of this narrative review is to analyze literature on rare genetic syndromes affecting dento-oro-maxillofacial structures (teeth, maxillary bones, oral soft tissues, or mixed) and to propose a classification according to the detected oral abnormalities. In addition, five significant cases of rare genetic syndromes are presented. The Scale for the Assessment of Narrative Review Articles (SANRA) was followed for this review. From 674 papers obtained through PubMed search, 351 were selected. Sixty-two rare genetic syndromes involving oral manifestations were found and classified. The proposed classification aims to help the clinician to easily understand which dento-oro-maxillofacial findings might be expected in the presence of each rare genetic syndrome. This immediate framework may both help in the diagnosis of dento-oro-maxillofacial anomalies related to the underlying pathology as well as facilitate the drafting of treatment plans with the involvement of a multidisciplinary team.

Gene4HL: An Integrated Genetic Database for Hearing Loss

Hearing loss (HL) is one of the most common disabilities in the world. In industrialized countries, HL occurs in 1–2/1,000 newborns, and approximately 60% of HL is caused by genetic factors. Next generation sequencing (NGS) has been widely used to identify many candidate genes and variants in patients with HL, but the data are scattered in multitudinous studies. It is a challenge for scientists, clinicians, and biologists to easily obtain and analyze HL genes and variant data from these studies. Thus, we developed a one-stop database of HL-related genes and variants, Gene4HL (http://www.genemed.tech/gene4hl/), making it easy to catalog, search, browse and analyze the genetic data. Gene4HL integrates the detailed genetic and clinical data of 326 HL-related genes from 1,608 published studies, along with 62 popular genetic data sources to provide comprehensive knowledge of candidate genes and variants associated with HL. Additionally, Gene4HL supports the users to analyze their own genetic engineering network data, performs comprehensive annotation, and prioritizes candidate genes and variations using custom parameters. Thus, Gene4HL can help users explain the function of HL genes and the clinical significance of variants by correlating the genotypes and phenotypes in humans.

CHARGE syndrome: A case report of two new CDH7 gene mutations

CHARGE syndrome is a genetic disorder comprising the following clinical features: coloboma, heart defects, choanal atresia, retardation (of growth and development), as well as genitourinary and ear abnormalities. This syndrome is caused by mutations in the CDH7 gene, located on chromosome 8 (8q12). We present two new gene mutations in two patients with CHARGE syndrome, not previously reported in the scientific literature. Both of these patients clearly demonstrate the difference in the clinical expression of this syndrome, with patient 1 having a greater clinical severity compared to patient 2. We conclude that although in the scientific literature to date there is no clear correlation between a patient's genotype and phenotype expression, we can assume from the cases we present that a correlation does in fact exist. Specifically, missense mutations (as in case of patient 2) are associated with milder clinical expression, whereas mutations which result in truncation of the CDH7 protein (as in the case of patient 1 having a nonsense mutation) may be associated with a more severe clinical expression.

Bilateral Choanal Atresia and Endoscopic Surgery: A Chance for CHARGE Patients

Bilateral choanal atresia (CA) is a rare congenital malformation frequently associated with other anomalies. CHARGE association is closely linked to bilateral CA. The aim of this study was to describe the outcomes of the endoscopic repair in bilateral CA, and to assess the role of postoperative nasal stenting in two cohorts of CHARGE-associated and non-syndromic CA. Thirty-nine children were retrospectively analyzed (16 patients had CHARGE-associated CA). The rate of postoperative neochoanal restenosis was 31.3% in the CHARGE population, and 47.8% in the non-syndromic CA cohort. Data on postoperative synechiae and granulation tissue formation, need for endonasal toilette and dilation procedures, and number of procedures per patient were presented. Stent positioning led to a higher number of postoperative dilation procedures per patient in the non-syndromic cohort (p = 0.018), and to a higher rate of restenosis both in the CHARGE-associated, and non-syndromic CA populations. Children with CHARGE-associated and non-syndromic bilateral CA benefitted from endonasal endoscopic CA correction. The postoperative application of an endonasal stent should be carefully evaluated.

Visual Function and Ophthalmological Findings in CHARGE Syndrome: Revision of Literature, Definition of a New Clinical Spectrum and Genotype Phenotype Correlation

CHARGE syndrome (CS) is a rare genetic disease causing multiple anatomical defects and sensory impairment. Visual function is usually reported by caregivers and has never been described with a structured behavioral assessment. Our primary objective was to describe ocular abnormalities, visual function and genotype–ocular-phenotype correlation in CS. A prospective monocentric cohort study was performed on 14 children with CS carrying pathogenic CHD7 variants. All children underwent ophthalmological evaluation and structured behavioral assessment of visual function. The VISIOCHARGE questionnaire was administered to parents. Colobomas were present in 93% of patients. Genotype–phenotype correlation documented mitigated features in a subset of patients with intronic pathogenic variants predicted to affect transcript processing, and severe features in patients with frameshift/nonsense variants predicting protein truncation at the N-terminus. Abnormal visual function was present in all subjects, with different degrees of impairment. A significant correlation was found between visual function and age at assessment (p-value = 0.025). The present data are the first to characterize visual function in CS patients. They suggest that hypomorphic variants might be associated with milder features, and that visual function appears to be related to age. While studies with larger cohorts are required for confirmation, our data indicate that experience appears to influence everyday use of visual function more than ocular abnormalities do.

Deformity Reconstruction Surgery for Tibial Hemimelia

Tibial hemimelia is a rare congenital deficiency with a wide spectrum of pathology and deformity. This paper aims to give a comprehensive review of tibial hemimelia, with a concise summary of the history, pathology, and clinical findings of tibial hemimelia, while providing treatment recommendations and a review of the current literature. Classifications and surgical treatments are discussed, including amputation, limb reconstruction, and lengthening. Type-specific treatments are also discussed, including staged distraction correction of joint contractures of knee and ankle, Weber patelloplasty, fibular centralization, knee and ankle arthrodesis, implantable articulated distractors, and the role of femoral shortening. Amputation is a simpler and easier solution for many patients; however, reconstruction options continue to evolve, improve, and provide better functional outcomes in many cases. Factors favoring surgical reconstruction include the presence of a knee joint/proximal tibia, and the presence of a patella and quadriceps mechanism.

Embryology, Malformations, and Rare Diseases of the Cochlea

Despite the low overall prevalence of individual rare diseases, cochlear dysfunction leading to hearing loss represents a symptom in a large proportion. The aim of this work was to provide a clear overview of rare cochlear diseases, taking into account the embryonic development of the cochlea and the systematic presentation of the different disorders. Although rapid biotechnological and bioinformatic advances may facilitate the diagnosis of a rare disease, an interdisciplinary exchange is often required to raise the suspicion of a rare disease. It is important to recognize that the phenotype of rare inner ear diseases can vary greatly not only in non-syndromic but also in syndromic hearing disorders. Finally, it becomes clear that the phenotype of the individual rare diseases cannot be determined exclusively by classical genetics even in monogenetic disorders.

Chromatin remodeller CHD7 is required for GABAergic neuron development by promoting PAQR3 expression

Mutations in the chromatin remodeller‐coding gene CHD7 cause CHARGE syndrome (CS). CS features include moderate to severe neurological and behavioural problems, clinically characterized by intellectual disability, attention‐deficit/hyperactivity disorder and autism spectrum disorder. To investigate the poorly characterized neurobiological role of CHD7, we here generate a zebrafish chd7^−/− model. chd7^−/− mutants have less GABAergic neurons and exhibit a hyperactivity behavioural phenotype. The GABAergic neuron defect is at least in part due to downregulation of the CHD7 direct target gene paqr3b, and subsequent upregulation of MAPK/ERK signalling, which is also dysregulated in CHD7 mutant human cells. Through a phenotype‐based screen in chd7^−/− zebrafish and Caenorhabditis elegans, we show that the small molecule ephedrine restores normal levels of MAPK/ERK signalling and improves both GABAergic defects and behavioural anomalies. We conclude that chd7 promotes paqr3b expression and that this is required for normal GABAergic network development. This work provides insight into the neuropathogenesis associated with CHD7 deficiency and identifies a promising compound for further preclinical studies.

Antenatal diagnosis of CHARGE syndrome: Prenatal ultrasound findings and crucial role of fetal dysmorphic signs. About a series of 10 cases and review of literature

Although the prognosis of CHARGE syndrome can be highly variable from mild until severe, final diagnosis is difficult to establish in utero. The aim of our study is to compare antenatal and postnatal findings in a retrospective cohort of 10 successive patients with a positive CHD7 gene variant in order to identify the specific prenatal features for CHARGE syndrome diagnosis. Fetal ultrasound, follow-up and supplementary investigations are collected and compared to postnatal findings. Congenital heart defect (7/10), choanal atresia (7/10) and tracheoesophageal atresia (4/10) are the most frequent fetal anomalies found. Inner and external ear anomalies appear as the keystone (constant features) for prenatal diagnosis of CHARGE syndrome in fetuses with multiple anomalies and normal microarray karyotype. External ear malformations are identified in all cases by 3D ultrasound when carefully evaluated. MRI and temporal bone CT-Scan are second line useful tools to assess the diagnosis when looking for semicircular canal agenesis, arhinencephaly and/or choanal atresia. Before availability of prenatal exome sequencing in clinical routine, present findings lead to the recommendation that fetuses, with congenital heart defect (mainly septal and conotruncal), cleft lip/palate or unexplained polyhydramnios should carefully be screened for clues suggesting CHARGE syndrome using 2D and 3D ultrasound, MRI and temporal bone CT-Scan. When CHARGE syndrome is suspected with normal molecular karyotype, CHD7 gene sequencing must be offered.

Inborn errors of immunity associated with characteristic phenotypes

OBJECTIVES

The aim of the report is to describe the main immunodeficiencies with syndromic characteristics according to the new classification of Inborn Errors of Immunity.

DATA SOURCE

The data search was centered on the PubMed platform on review studies, meta-analyses, systematic reviews, case reports and a randomized study published in the last 10 years that allowed the characterization of the several immunological defects included in this group.

DATA SYNTHESIS

Immunodeficiencies with syndromic characteristics include 65 immunological defects in 9 subgroups. The diversity of clinical manifestations is observed in each described disease and may appear early or later, with variable severity. Congenital thrombocytopenia, syndromes with DNA repair defect, immuno-osseous dysplasias, thymic defects, Hyper IgE Syndrome, anhidrotic ectodermal dysplasia with immunodeficiency and purine nucleoside phosphorylase deficiency were addressed.

CONCLUSIONS

Immunological defects can present with very different characteristics; however, the occurrence of infectious processes, autoimmune disorders and progression to malignancy may suggest diagnostic research. In the case of diseases with gene mutations, family history is of utmost importance.

What can clinical immunology learn from inborn errors of epigenetic regulators?

The epigenome is at the interface between environmental factors and the genome, regulating gene transcription, DNA repair, and replication. Epigenetic modifications play a crucial role in establishing and maintaining cell identity and are especially crucial for neurology, musculoskeletal integrity, and the function of the immune system. Mutations in genes encoding for the components of the epigenetic machinery lead to the development of distinct disorders, especially involving the central nervous system and host defense. In this review, we focus on the role of epigenetic modifications for the function of the immune system. By studying the immune phenotype of patients with monogenic mutations in components of the epigenetic machinery (inborn errors of epigenetic regulators), we demonstrate the importance of DNA methylation, histone modifications, chromatin remodeling, noncoding RNAs, and mRNA processing for immunity. Moreover, we give a short overview on therapeutic strategies targeting the epigenome.

Neonatal Metabolic Acidosis in the Neonatal Intensive Care Unit: What Are the Genetic Causes?

Neonatal metabolic acidosis (NMA) is a common problem, particularly in critically ill patients in neonatal intensive care units (NICUs). Complex etiologies and atypical clinical signs make diagnosis difficult; thus, it is crucial to investigate the underlying causes of NMA rapidly and provide disorder-specific therapies. Our study aims to provide an overview of the genetic causes of NMA in patients from NICUs. We performed next-generation sequencing (NGS) on neonates with NMA from January 2016 to December 2019. Clinical features, genetic diagnoses, and their effects on clinical interventions were collected for analysis. In the 354 enrolled patients, 131 (37%) received genetic diagnoses; 95 (72.5%) of them were autosomal recessively inherited diseases. Two hundred and fifteen variants spanning 57 genes were classified as pathogenic (P) or likely pathogenic (LP) in 131 patients. The leading cause was metabolic disorders due to 35 genes found in 89 patients (68%). The other 42 NMA patients (32%) with 22 genes had malformations and renal, neuromuscular, and immune-hematological disorders. Seven genes (MMUT, MMACHC, CHD7, NPHS1, OTC, IVD, and PHOX2B) were noted in more than four patients, accounting for 48.9% (64/131) of the identified P/LP variants. Forty-six diagnosed patients with uncorrected NMA died or gave up. In conclusion, 37% of neonates with metabolic acidosis had genetic disorders. Next-generation sequencing should be considered when investigating the etiology of NMA in NICUs. Based on early molecular diagnoses, valuable treatment options can be provided for some genetic diseases to achieve better outcomes.

Glioma stem cells and their roles within the hypoxic tumor microenvironment

Tumor microenvironments are the result of cellular alterations in cancer that support unrestricted growth and proliferation and result in further modifications in cell behavior, which are critical for tumor progression. Angiogenesis and therapeutic resistance are known to be modulated by hypoxia and other tumor microenvironments, such as acidic stress, both of which are core features of the glioblastoma microenvironment. Hypoxia has also been shown to promote a stem-like state in both non-neoplastic and tumor cells. In glial tumors, glioma stem cells (GSCs) are central in tumor growth, angiogenesis, and therapeutic resistance, and further investigation of the interplay between tumor microenvironments and GSCs is critical to the search for better treatment options for glioblastoma. Accordingly, we summarize the impact of hypoxia and acidic stress on GSC signaling and biologic phenotypes, and potential methods to inhibit these pathways.

Sporadic Case of CHARGE Syndrome With Chromodomain-Helicase-DNA-Binding Protein 7 (CDH7) Gene Mutation

CHARGE syndrome with chromodomain-helicase-DNA-binding protein 7 (CDH7) gene mutation is a genetic disease with an autosomal dominant gene. This syndrome involves a combination of six congenital anomalies (heart anomalies, coloboma of the eye, retardation of the growth or development, atresia of the choana, ear anomalies, and genital anomalies). Here, we present a case of a 15-month-old male child who was born to a 23-year-old healthy mother with no history of any exposure to teratogenic materials or drugs. The patient was delivered by cesarean section because of the failure of progression at 39 weeks of pregnancy with several health problems that started with the respiratory system right after birth. On examination, he was found to be suffering from several congenital anomalies, including heart, face, eyes, ears, and genitalia. A genetic analysis was performed for the patient, and a mutation in the CDH7 gene was found. The patient was diagnosed as a sporadic case of CHARGE syndrome. The patient's treatment plan is a multidisciplinary team effort to alleviate his quality of life and further increase life expectancy.

Further delineation of a recognizable type of syndromic short stature caused by biallelic SEMA3A loss-of-function variants

The semaphorin protein family is a diverse set of extracellular signaling proteins that perform fundamental roles in the development and operation of numerous biological systems, notably the nervous, musculoskeletal, cardiovascular, endocrine, and reproductive systems. Recently, recessive loss-of-function (LoF) variants in SEMA3A (semaphorin 3A) have been shown to result in a recognizable syndrome characterized by short stature, skeletal abnormalities, congenital heart defects, and variable additional anomalies. Here, we describe the clinical and molecular characterization of a female patient presenting with skeletal dysplasia, hypogonadotropic hypogonadism (HH), and anosmia who harbors a nonsense variant c.1633C>T (p.Arg555*) and a deletion of exons 15, 16, and 17 in SEMA3A in the compound heterozygous state. These variants were identified through next-generation sequencing analysis of a panel of 26 genes known to be associated with HH/Kallmann syndrome. Our findings further substantiate the notion that biallelic LoF SEMA3A variants cause a syndromic form of short stature and expand the phenotypic spectrum associated with this condition to include features of Kallmann syndrome.