A novel CHD7 variant disrupting acceptor splice site in a patient with mild features of CHARGE syndrome: a case report.

BACKGROUND: CHARGE syndrome (MIM# 214800)-which is characterised by a number of congenital anomalies including coloboma, ear anomalies, deafness, facial anomalies, heart defects, atresia choanae, genital hypoplasia, growth retardation, and developmental delay-is caused by a heterozygous variant in the CHD7 (MIM# 608892) gene located on chromosome 8q12. We report the identification of a novel c.5535-1G > A variant in CHD7 and provide the evaluation of its effect on pre-mRNA splicing. CASE PRESENTATION: In this study, we report on a female presenting features of CHARGE syndrome. A novel heterozygous CHD7 variant c.5535-1G > A located in the acceptor splice site of intron 26 was identified in the proband's DNA sample after analysis of whole exome sequencing data. In silico predictions indicating that the variant is probably pathogenic by affecting pre-mRNA splicing were verified by genetic analysis based on reverse transcription of the patient's RNA followed by PCR amplifications performed on synthesised cDNA and Sanger sequencing. Sanger sequencing of cDNA revealed that the c.5535-1G > A variant disrupts the original acceptor splice site and activates a cryptic splice site only one nucleotide downstream of the pathogenic variant site. This change causes the omission of the first nucleotide of exon 27, leading to a frameshift in the mRNA of the CHD7 gene. Our results suggest that the alteration induces the premature truncation of the CHD7 protein (UniProtKB: Q9P2D1), thus resulting in CHARGE syndrome. CONCLUSION: Genetic analysis of novel splice site variant underlines its importance for studying the pathogenic splicing mechanism as well as for confirming a diagnosis.

Auditory Skills following Cochlear Implantation in Children with the Charge Syndrome.

OBJECTIVES: To assess the auditory outcomes and skills of pediatric cochlear implant (CI) users with the CHARGE syndrome. To determine the influence of inner ear malformations on the surgical procedure and speech understanding outcomes in this population. STUDY DESIGN: Observational, retrospective study. MATERIALS AND METHODS: Imaging, auditory testing, intraoperative findings, complications, and postoperative auditory skills and outcomes of pediatric CI users with CHARGE syndrome were recorded. RESULTS: 6 children (8 ears) were included, 5 of whom had prelingual deafness. Their mean age at implantation was 37 months. Six of the 8 ears presented cochlear malformation; the most frequent was hypoplasia type III. Intraoperatively, the transmastoid facial recess approach was used in 5 ears, and abnormalities of facial nerve anatomy were found in 5 ears. All electrode insertions were complete. All children were, to a varying degree, able to detect and identify sound. Verbalization skills were developed by 2 children, 1 of whom used oral language as his primary mode of communication. CONCLUSIONS: Cochlear implantation performed by an experienced surgeon in patients with the CHARGE syndrome is a safe procedure with adequate treatment planning. All children had improved auditory skills although the improvement was variable.

Phenotypic spectrum of neonatal CHARGE syndrome. / Espectro fenotípico de Síndrome de CHARGE neonatal.

INTRODUCTION: CHARGE syndrome is a genetic disorder of wide phenotypic variability, of autosomal dominant in heritance, caused by pathogenic variants in the CHD7 gene. OBJECTIVE: To describe the broad pheno typic spectrum of neonatal CHARGE syndrome, heterozygous for the CHD7 gene, and the usefulness of genome sequencing in diagnostic confirmation, considering differential diagnoses. CLINICAL CASE: 34-week preterm newborn, with severe prenatal history of polyhydramnios, increased nuchal trans- lucency, and hyperechogenic cardiac focus, with a TORCH study that ruled out congenital infection. Peripheral facial paralysis, choanal atresia, multiple dysmorphisms, congenital heart disease, and bilateral retinochoroidal coloboma were observed at birth. The neuroimaging study showed hypo plasia of the cochlea and bilateral semicircular canals, and pontocerebellar hypoplasia. The auditory evoked potentials showed deep right-sided sensorineural hearing loss and left anacusis. The patient developed hypocalcemia and immunological alterations, confirming hypoparathyroidism and thy mus hypoplasia. The karyogram was normal and 22q11.2 microdeletion was excluded through mul tiplex ligation-dependent probe amplification (MPLA). A pathogenic variant in the CHD7 gene was detected that confirmed the clinical suspicion of CHARGE syndrome. CONCLUSIONS: The overlap of clinical characteristics of CHARGE syndrome requires molecular genetic confirmation, considering differences in evolution, therapies, and recurrence risks with other genetic syndromes.

Phenotypic spectrum of CHARGE syndrome based on clinical characteristics

Background/aim: CHARGE syndrome is a rare autosomal dominant disease with multiple congenital anomalies and cognitive impairment, which is caused by mutations in the CHD7 gene. This study aimed to disclose the mild end of the phenotypic spectrum of CHARGE syndrome, which has a highly variable expressivity. Materials and methods: Twenty-one patients who had at least one of the major symptoms of CHARGE syndrome (coloboma, choanal atresia, characteristic ear anomalies, semicircular canal hypoplasia, and cranial nerve anomalies) were included in the study. All patients were tested for karyotype analysis and CHD7 gene mutation/deletion. Results: In the study population, 6 different mutations were detected in 5 patients, and 2 different polymorphisms were detected in the CHD7 gene in 3 patients. MLPA analysis of all coding exons of the CHD7 gene revealed no pathogenic deletion/duplication. Conclusion: CHARGE syndrome should be considered as a differential diagnosis to detect the mild end of the spectrum, even if the patient does not fit the criteria.

CHARGE syndrome gastrointestinal involvement: from mouth to anus.

CHARGE syndrome is an autosomal dominant disorder that occurs as a result of a heterozygous loss-of-function mutation in the chromodomain helicase DNA-binding (CHD7) gene, which is important for neural crest cell formation. Gastrointestinal (GI) symptoms and feeding difficulties are highly prevalent but are often a neglected area of diagnosis, treatment, and research. Cranial nerve dysfunction, craniofacial abnormalities, and other physical manifestations of this syndrome lead to gut dysmotility, sensory impairment, and oral-motor function abnormalities. Over 90% of children need tube feeding early in their life and many experience weak sucking/chewing, gastroesophageal reflux disease (GERD), and aspiration. The mainstay of treatment thus far has consisted of feeding therapy, GERD medications, Nissen fundoplication, gastrostomy/jejunostomy, and food texture limitation. Owing to the multitude of severe medical issues associated with this genetic disorder, GI involvement is often overlooked. Here, we report on five patients with CHARGE syndrome who manifested a range of severe GI and feeding difficulties.

Experiences in feeding and gastrointestinal dysfunction in children with CHARGE syndrome.

Feeding issues are very common in individuals with CHARGE syndrome and can lead to increased morbidity and mortality. The aim of this study was to expand upon the limited knowledge base of feeding and gastrointestinal issues in individuals with CHARGE syndrome. Parents of individuals (age range 1-18 years) with CHARGE syndrome, with or without feeding/gastrointestinal issues, were recruited through international CHARGE syndrome associations and CHARGE syndrome Facebook pages. Parents completed three questionnaires: CHARGE diagnostic characteristics; Pediatric Assessment Scale for Severe Feeding Problems © and PedsQL™ Gastrointestinal Symptoms Scale; and open-ended questions. Sixty-nine completed questionnaires were included in the study analysis (median age 7; 58% females). Individuals who were completely tube fed (n = 21) had significantly more feeding difficulties than individuals who were either partially (n = 26) or completely orally fed (n = 20; p < 0.001). Tube fed individuals also experienced more problematic gastrointestinal symptoms (p < 0.001). Constipation (n = 19, 30%), vomiting (n = 12, 19%), and choking (n = 11, 17%) were reported by parents as the greatest challenges. Problems exist throughout the entire gastrointestinal tract in many individuals with CHARGE syndrome. These issues are more common in individuals who receive nutrition completely through a feeding tube compared to individuals with at least partial oral feeding behaviors.

Duplication 2p25 in a child with clinical features of CHARGE syndrome.

CHARGE syndrome is a dominant disorder characterized by ocular colobomata, heart defects, choanal atresia, retardation of growth and development, genital hypoplasia, and ear abnormalities including deafness and vestibular disorders. The majority of individuals with CHARGE have pathogenic variants in the gene encoding CHD7, a chromatin remodeling protein. Here, we present a 15-year-old girl with clinical features of CHARGE syndrome and a de novo 6.5 Mb gain of genomic material at 2p25.3-p25.2. The duplicated region contained 24 genes, including the early and broadly expressed transcription factor gene SOX11. Analysis of 28 other patients with CHARGE showed no SOX11 copy number changes or pathogenic sequence variants. To our knowledge, this child's chromosomal abnormality is unique and represents the first co-occurrence of duplication 2p25 and clinical features of CHARGE syndrome. We compare our patient's phenotype to ten previously published patients with isolated terminal duplication 2p, and elaborate on the clinical diagnosis of CHARGE in the context of atypical genetic findings.

Spontaneous postnatal growth is reduced in children with CHARGE syndrome.

AIM: There is a scarcity of data on postnatal growth in children with CHARGE syndrome, a genetic disorder. This study analysed spontaneous growth and weight in German children with CHARGE from birth to the age of 6 years. METHODS: This was a retrospective analysis of 19 children, nine females and 10 males, using data from child health records. Standard deviation scores (SDS) were calculated based on Swiss references. RESULTS: The median birthweight was 2950 g (-0.78 SDS), and the birth length was 49 cm (-0.5 SDS). There was a significant loss of median body length, at around 4 weeks of age from -0.5 to -2.3 SDS (p < 0.05). At 1 year, the median length was -2.6 SDS and it remained low until 5 years of age when the lowest value was found to be -2.8 SDS. There was a significant increase in median body mass index (BMI) from -1.15 SDS at 1 year to -0.15 SDS at 5 years (p < 0.01). CONCLUSION: Children with CHARGE syndrome displayed almost normal length and weight data at birth, with just one of the 19 infants having below average length for gestational age. However, postnatal growth was retarded during infancy and childhood, and the increase in BMI-SDS did not correlate with growth.

Reproductive dysfunction and decreased GnRH neurogenesis in a mouse model of CHARGE syndrome.

CHARGE is a multiple congenital anomaly disorder and a common cause of pubertal defects, olfactory dysfunction, growth delays, deaf-blindness, balance disorders and congenital heart malformations. Mutations in CHD7, the gene encoding chromodomain helicase DNA binding protein 7, are present in 60-80% of individuals with the CHARGE syndrome. Mutations in CHD7 have also been reported in the Kallmann syndrome (olfactory dysfunction, delayed puberty and hypogonadotropic hypogonadism). CHD7 is a positive regulator of neural stem cell proliferation and olfactory sensory neuron formation in the olfactory epithelium, suggesting that the loss of CHD7 might also disrupt development of other neural populations. Here we report that female Chd7(Gt/+) mice have delays in vaginal opening and estrus onset, and erratic estrus cycles. Chd7(Gt/+) mice also have decreased circulating levels of luteinizing hormone and follicle-stimulating hormone but apparently normal responsiveness to gonadotropin-releasing hormone (GnRH) agonist and antagonist treatment. GnRH neurons in the adult Chd7(Gt/+) hypothalamus and embryonic nasal region are diminished, and there is decreased cellular proliferation in the embryonic olfactory placode. Expression levels of GnRH1 and Otx2 in the hypothalamus and GnRHR in the pituitary are significantly reduced in adult Chd7(Gt/+) mice. Additionally, Chd7 mutant embryos have CHD7 dosage-dependent reductions in expression levels of Fgfr1, Bmp4 and Otx2 in the olfactory placode. Together, these data suggest that CHD7 has critical roles in the development and maintenance of GnRH neurons for regulating puberty and reproduction.

Evidence for replicative mechanism in a CHD7 rearrangement in a patient with CHARGE syndrome.

Haploinsufficiency of CHD7 (OMIM# 608892) is known to cause CHARGE syndrome (OMIM# 214800). Molecular testing supports a definitive diagnosis in approximately 65-70% of cases. Most CHD7 mutations arise de novo, and no mutations affecting exon-7 have been reported to date. We report on an 8-year-old girl diagnosed with CHARGE syndrome that was referred to our laboratory for comprehensive CHD7 gene screening. Genomic DNA from the subject with a suspected diagnosis of CHARGE was isolated from peripheral blood lymphocytes and comprehensive Sanger sequencing, along with deletion/duplication analysis of the CHD7 gene using multiplex ligation-dependent probe amplification (MLPA), was performed. MLPA analysis identified a reduced single probe signal for exon-7 of the CHD7 gene consistent with potential heterozygous deletion. Long-range PCR breakpoint analysis identified a complex genomic rearrangement (CGR) leading to the deletion of exon-7 and breakpoints consistent with a replicative mechanism such as fork stalling and template switching (FoSTeS) or microhomology-mediated break-induced replication (MMBIR). Taken together this represents the first evidence for a CHD7 intragenic CGR in a patient with CHARGE syndrome leading to what appears to be also the first report of a mutation specifically disrupting exon-7. Although likely rare, CGR may represent an overlooked mechanism in subjects with CHARGE syndrome that can be missed by current sequencing and dosage assays.

Antenatal spectrum of CHARGE syndrome in 40 fetuses with CHD7 mutations.

BACKGROUND: CHARGE syndrome is a rare, usually sporadic disorder of multiple congenital anomalies ascribed to a CHD7 gene mutation in 60% of cases. Although the syndrome is well characterised in children, only one series of 10 fetuses with CHARGE syndrome has been reported to date. Therefore, we performed a detailed clinicopathological survey in our series of fetuses with CHD7 mutations, now extended to 40 cases. CHARGE syndrome is increasingly diagnosed antenatally, but remains challenging in many instances. METHOD: Here we report a retrospective study of 40 cases of CHARGE syndrome with a CHD7 mutation, including 10 previously reported fetuses, in which fetal or neonatal clinical, radiological and histopathological examinations were performed. RESULTS: Conversely to postnatal studies, the proportion of males is high in our series (male to female ratio 2.6:1) suggesting a greater severity in males. Features almost constant in fetuses were external ear anomalies, arhinencephaly and semicircular canal agenesis, while intrauterine growth retardation was never observed. Finally, except for one, all other mutations identified in our antenatal series were truncating, suggesting a possible phenotype-genotype correlation. CONCLUSIONS: Clinical analysis allowed us to refine the clinical description of CHARGE syndrome in fetuses, describe some novel features and set up diagnostic criteria in order to help the diagnosis of CHARGE syndrome after termination of pregnancies following the detection of severe malformations.

CHARGE syndrome: diagnosis and clinical management in the NICU.

CHARGE syndrome is a condition that has historically been diagnosed on the basis of the clinical findings of coloboma, heart disease, choanal atresia, restricted growth, and/or central nervous system anomalies, genital hypoplasia, and ear anomalies and/or deafness. Recently, researchers have discovered a genetic link, specifically, a strong association between the CHARGE phenotype and a mutation of the CHD 7 gene on the long arm of chromosome 8. Diagnosis now can be confirmed but not excluded with a positive mutation of this gene. This article offers an explanation of the diagnostic process as well as a description of the physical assessment and corresponding clinical implications of CHARGE syndrome in the neonatal population.

Diagnostics and therapy of bilateral choanal atresia in association with CHARGE syndrome.

BACKGROUND: Bilateral choanal atresia in patients with CHARGE syndrome becomes symptomatic immediately after birth. A prompt diagnosis, the implementation of sufficient preliminary measures, and the delivery of surgical therapy are crucial. This article is intended to assist in terms of diagnostics and a therapy recommendation. METHODS: We performed a retrospective study using the medical records of all newborns in the University Hospital in Bonn, diagnosed with bilateral choanal atresia and CHARGE syndrome and underwent surgery at the Department of Otorhinolaryngology, Head and Neck Surgery. RESULTS: A total of 21 patients have been treated with a unilateral or bilateral choanal atresia. 14 patients were primarily treated with transnasal endoscopy or underwent transnasal endoscopic surgery as a follow-up intervention (73.68%). Nine patients had a syndromal appearance, which was considered a definite diagnosis in six patients (five with CHARGE syndrome). All five patients with CHARGE syndrome received transnasal endoscopic treatment and a stent was inserted. DISCUSSION: Bilateral choanal atresia can be a life-threatening situation requiring acute measures. The therapeutic trend goes towards transnasal endoscopic resection. Primary intervention should be: minimally invasive, one-stage surgery, functional, and associated with low complication rates. Patency can be increased by saline irrigations, topical corticosteroids, endoscopic controls, and regular dilatation. The insertion of stents is controversially discussed but can be useful in syndromal patients. However, adjuvant therapy with a stent and mitomycin C is increasingly being abandoned. A significantly higher recurrence rate must be expected in association with CHARGE syndrome. Stenting should be considered on an individual basis. Continuous training and support of the parents are obligatory.

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.

Functional Vision Analysis in Patients With CHARGE Syndrome.

PURPOSE: To evaluate functional vision in patients with CHARGE syndrome (coloboma, heart defects, atresia of the choanae, retardation of growth and development, genital and urinary anomalies, and ear anomalies) by using a new questionnaire entitled VISIOCHARGE. METHODS: Ophthalmological data including fundus description and visual acuity, when available, were extracted from the charts of 83 patients with CHARGE syndrome, and the VISIOCHARGE questionnaire was prospectively mailed to 55 of those patients. The answers from the 36 responders (18 males) allowed for the calculation of three scores that assessed distance vision, near vision, and overall ability scores. RESULTS: Visual acuity measurements were extracted from the charts of 20 of the 36 patients. The mean visual acuity was 20/50. The mean distance vision score of 0.62 ± 0.30 and near vision score of 0.78 ± 0.23 were correlated with visual acuity in the 20 patients (ρ = 0.64, P = .002 and ρ = 0.61, P = .005, respectively) and were associated with the severity of colobomatous malformation (P = .049 and P = .008, respectively). Severity of the ocular malformation was not associated with the overall ability score (P = .64). CONCLUSIONS: The VISIOCHARGE questionnaire is feasible for patients with CHARGE syndrome and may help in the assessment of visual function. The mean visual acuity and answers to the VISIOCHARGE questionnaire showed relatively good visual skills in patients with CHARGE syndrome in everyday life, even in those with bilateral colobomas, which contrasts with the pessimistic conclusions usually resulting from the initial fundus examination. [J Pediatr Ophthalmol Strabismus. 2020;57(2):120-128.].

CHARGE syndrome patient with novel CHD7 mutation presenting with severe laryngomalacia and feeding difficulty.

We report a case of CHARGE syndrome with atypical phenotype and a novel mutation in the CHD7 gene. Laryngomalacia and swallowing difficulties are prominent features in this case. These are commonly found in patients with CHARGE syndrome and are well described in previous studies. However, with the traditional diagnostic criteria, diagnosis is difficult without the presence of coloboma or choanal atresia. Early diagnosis is possible with the aid of clinical genetics. The current diagnostic criteria would need to be broadened with the inclusion of pathogenic CHD7 variant status as a major criterion. Further research on the function of CHD7 gene may also give us more insight on the pathogenic mechanism of various clinical features of CHARGE syndrome.

Parent survey of sleep problems among children with CHARGE syndrome.

Sleep problems are common among children, especially those with developmental disabilities, visual impairments, and behavioral problems. Past research has indicated a particularly high prevalence of clinically-relevant sleep problems for children with CHARGE syndrome, who often possess all three of these qualities. To gather additional information regarding the nature of these sleep problems and how they are most commonly treated amongst parents, an explorative survey was conducted with 30 parents of children with CHARGE syndrome with comorbid sleep problems using the Sleep Disturbance Scale for Children, as well as demographic and sleep questionnaires developed for use in this study. Our findings indicated that problems of sleep initiation and maintenance were most commonly reported, consistent with previous research. Parents most often reported the following factors suspected of contributing to sleep problems: self-regulation difficulties, teeth grinding, hormonal imbalance, problem behaviors, and anxiety. The most commonly administered treatments were reported to be the use of positive bedtime routines, melatonin treatment, the use of a weighted blanket, and prescription medications, respectively. While parents reported overall that they felt all three of these intervention strategies were slightly effective at improving their child's sleep problem, the use of positive bedtime routines and melatonin treatment were perceived as more effective by parents. These results aid professionals in the selection of future research and intervention strategies to recommend for parents of children with CHARGE syndrome.

Chemical screens in a zebrafish model of CHARGE syndrome identifies small molecules that ameliorate disease-like phenotypes in embryo.

CHARGE syndrome is an autosomal dominant congenital disorder caused primarily by mutations in the CHD7 gene. Using a small molecule screen in a zebrafish model of CHARGE syndrome, we identified 4 compounds that rescue embryos from disease-like phenotypes. Our screen yielded DAPT, a Notch signaling inhibitor that could ameliorate the craniofacial, cranial neuronal and myelination defects in chd7 morphant zebrafish embryos. We discovered that Procainamide, an inhibitor of DNA methyltransferase 1, was able to recover the pattern of expression of isl2a, a cranial neuronal marker while also reducing the effect on craniofacial cartilage and myelination. M344, an inhibitor of Histone deacetylases had a strong recovery effect on craniofacial cartilage defects and could also modestly revert the myelination defects in zebrafish embryos. CHIC-35, a SIRT1 inhibitor partially restored the expression of isl2a in cranial neurons while causing a partial reversion of myelination and craniofacial cartilage defects. Our results suggest that a modular approach to phenotypic rescue in multi-organ syndromes might be a more successful approach to treat these disorders. Our findings also open up the possibility of using these compounds for other disorders with shared phenotypes.

An intronic mutation in Chd7 creates a cryptic splice site, causing aberrant splicing in a mouse model of CHARGE syndrome.

Alternate splicing is a critical regulator of gene expression in eukaryotes, however genetic mutations can cause erroneous splicing and disease. Most recorded splicing disorders are caused by mutations of splice donor/acceptor sites, however intronic mutations can affect splicing. Clinical exome analyses largely ignore intronic sequence, limiting the detection of mutations to within coding regions. We describe 'Trooper', a novel mouse model of CHARGE syndrome harbouring a pathogenic point mutation in Chd7. The mutation is 18 nucleotides upstream of exon 10 and creates a cryptic acceptor site, causing exon skipping and partial intron retention. This mutation, though detectable in exome sequence, was initially dismissed by computational filtering due to its intronic location. The Trooper strain exhibited many of the previously described CHARGE-like anomalies of CHD7 deficient mouse lines; including hearing impairment, vestibular hypoplasia and growth retardation. However, more common features such as facial asymmetry and circling were rarely observed. Recognition of these characteristic features prompted manual reexamination of Chd7 sequence and subsequent validation of the intronic mutation, highlighting the importance of phenotyping alongside exome analyses. The Trooper mouse serves as a valuable model of atypical CHARGE syndrome and reveals a molecular mechanism that may underpin milder clinical presentation of the syndrome.