Congenital heart defects in CHARGE: The molecular role of CHD7 and effects on cardiac phenotype and clinical outcomes

Fbrsl1 is required for heart development in Xenopus laevis and de novo variants in FBRSL1 can cause human heart defects

De novo truncating variants in fibrosin-like 1 (FBRSL1), a member of the AUTS2 gene family, cause a disability syndrome, including organ malformations such as heart defects. Here, we use Xenopus laevis to investigate whether Fbrsl1 plays a role in heart development. Xenopus laevis fbrsl1 is expressed in tissues relevant for heart development, and morpholino-mediated knockdown of Fbrsl1 results in severely hypoplastic hearts. Our data suggest that Fbrsl1 is required for the development of the first heart field, which contributes to the ventricle and the atria, but not for the second heart field, which gives rise to the outflow tract. The morphant heart phenotype could be rescued using a human N-terminal FBRSL1 isoform that contains an alternative exon, but lacks the AUTS2 domain. N-terminal isoforms carrying patient variants failed to rescue. Interestingly, a long human FBRSL1 isoform, harboring the AUTS2 domain, also did not rescue the morphant heart defects. Thus, our data suggest that different FBRSL1 isoforms may have distinct functions and that only the short N-terminal isoform, appears to be critical for heart development.

Variants in FOXC1 and FOXC2 identified in patients with conotruncal heart defects

Conotruncal heart defects (CTD), subtypes of congenital heart disease, result from abnormal cardiac outflow tract development (OFT). FOXC1 and FOXC2 are closely related members of the forkhead transcription factor family and play essential roles in the development of OFT. We confirmed their expression pattern in mouse and human embryos, identifying four variants in FOXC1 and three in FOXC2 by screening these two genes in 605 patients with sporadic CTD. Western blot demonstrated expression levels, while Dual-luciferase reporter assay revealed affected transcriptional abilities for TBX1 enhancer in two FOXC1 variants and three FOXC2 variants. This might result from the altered DNA-binding abilities of mutant proteins. These results indicate that functionally impaired FOXC1 and FOXC2 variants may contribute to the occurrence of CTD.

In-Depth Genomic Analysis: The New Challenge in Congenital Heart Disease

The use of next-generation sequencing has provided new insights into the causes and mechanisms of congenital heart disease (CHD). Examinations of the whole exome sequence have detected detrimental gene variations modifying single or contiguous nucleotides, which are characterised as pathogenic based on statistical assessments of families and correlations with congenital heart disease, elevated expression during heart development, and reductions in harmful protein-coding mutations in the general population. Patients with CHD and extracardiac abnormalities are enriched for gene classes meeting these criteria, supporting a common set of pathways in the organogenesis of CHDs. Single-cell transcriptomics data have revealed the expression of genes associated with CHD in specific cell types, and emerging evidence suggests that genetic mutations disrupt multicellular genes essential for cardiogenesis. Metrics and units are being tracked in whole-genome sequencing studies.

Human Genetics of Atrial Septal Defect

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

Co-Occurrence of Sensorineural Hearing Loss and Congenital Heart Disease: Etiologies and Management

OBJECTIVES/HYPOTHESIS

The co-occurrence of sensorineural hearing loss (SNHL) and congenital heart disease (CHD) is a rare condition with complex etiologies. The purpose of this study is to assess the etiologies, clinical features, and outcomes of cochlear implant (CI) in this patient population.

STUDY DESIGN

Case series and literature review.

METHODS

Clinical data of children who were diagnosed with SNHL and CHD and received CIs at a tertiary hospital from 2016 to 2021 were retrospectively analyzed. A literature review was performed to identify patients with SNHL and CHD.

FINDINGS

Of the 382 children who underwent cochlear implantation at our center, eight (2.1%) were diagnosed with SNHL and CHD. A literature review identified 1525 patients from 254 studies; the database therefore consisted of 1533 patients. The most common genetic etiologies of co-occurring SNHL and CHD were CHARGE syndrome (36.3%), Turner syndrome (8.4%), 22q11.2 deletion (3.0%), Noonan syndrome (2.9%), and Down syndrome (2.5%), whereas the most common non-genetic etiologies were congenital rubella syndrome (22.9%) and SNHL after early cardiac surgery (5.5%). Most of the patients presented with congenital, bilateral, severe-profound SNHL requiring early rehabilitation. Of the 126 children who received CIs at a median age of 2.5 years, half showed delayed speech development at last follow-up.

CONCLUSIONS

Co-occurring SNHL and CHD is a rare condition with complex etiologies. Timely hearing intervention with long-term follow-up and proper timing of heart surgery is essential for these children.

LEVEL OF EVIDENCE

4, case series Laryngoscope, 134:400-409, 2024.

Uncovering the Genetic Basis of Congenital Heart Disease: Recent Advancements and Implications for Clinical Management

Congenital heart disease (CHD) is the most prevalent hereditary disorder, affecting approximately 1% of all live births. A reduction in morbidity and mortality has been achieved with advancements in surgical intervention, yet challenges in managing complications, extracardiac abnormalities, and comorbidities still exist. To address these, a more comprehensive understanding of the genetic basis underlying CHD is required to establish how certain variants are associated with the clinical outcomes. This will enable clinicians to provide personalized treatments by predicting the risk and prognosis, which might improve the therapeutic results and the patient's quality of life. We review how advancements in genome sequencing are changing our understanding of the genetic basis of CHD, discuss experimental approaches to determine the significance of novel variants, and identify barriers to use this knowledge in the clinics. Next-generation sequencing technologies are unravelling the role of oligogenic inheritance, epigenetic modification, genetic mosaicism, and noncoding variants in controlling the expression of candidate CHD-associated genes. However, clinical risk prediction based on these factors remains challenging. Therefore, studies involving human-induced pluripotent stem cells and single-cell sequencing help create preclinical frameworks for determining the significance of novel genetic variants. Clinicians should be aware of the benefits and implications of the responsible use of genomics. To facilitate and accelerate the clinical integration of these novel technologies, clinicians should actively engage in the latest scientific and technical developments to provide better, more personalized management plans for patients.

Complete Isolation of Left Innominate Artery in a Patient With CHARGE Syndrome: Case Presentation and Review of Reported Cases

We report a rare case of complete isolation of the left innominate artery in a child with CHARGE (coloboma, heart defects, atresia choanae, growth retardation, genital abnormalities, and ear abnormalities) syndrome. This anatomical cluster had been undetected for a relatively large period of time and the patient was referred to us with an incomplete diagnosis even after multiple medical evaluations and a thoracic surgery during the neonatal period. In conclusion, to the best of our knowledge, this is the first case of a complete isolation of left innominate artery treated with a transcatheter approach.

Insights into the Cardiac Phenotype in 9p Deletion Syndrome: A Multicenter Italian Experience and Literature Review

Chromosome 9p deletion syndrome is a rare autosomal dominant disorder presenting with a broad spectrum of clinical features, including congenital heart defects (CHDs). To date, studies focused on a deep characterization of cardiac phenotype and function associated with this condition are lacking. We conducted a multicentric prospective observational study on a cohort of 10 patients with a molecular diagnosis of 9p deletion syndrome, providing a complete cardiological assessment through conventional echocardiography and tissue Doppler imaging echo modality. As a result, we were able to demonstrate that patients with 9p deletion syndrome without major CHDs may display subclinical cardiac structural changes and left-ventricle systolic and diastolic dysfunction. Albeit needing validation in a larger cohort, our findings support the idea that a complete cardiac assessment should be performed in patients with 9p deletion syndrome and should be integrated in the context of a long-term follow-up.

Diagnostic potential of the amniotic fluid cells transcriptome in deciphering mendelian disease: a proof-of-concept

RNA sequencing (RNA-seq) is emerging in genetic diagnoses as it provides functional support for the interpretation of variants of uncertain significance. However, the use of amniotic fluid (AF) cells for RNA-seq has not yet been explored. Here, we examined the expression of clinically relevant genes in AF cells (n = 48) compared with whole blood and fibroblasts. The number of well-expressed genes in AF cells was comparable to that in fibroblasts and much higher than that in blood across different disease categories. We found AF cells RNA-seq feasible and beneficial in prenatal diagnosis (n = 4) as transcriptomic data elucidated the molecular consequence leading to the pathogenicity upgrade of variants in CHD7 and COL1A2 and revising the in silico prediction of a variant in MYRF. AF cells RNA-seq could become a reasonable choice for postnatal patients with advantages over fibroblasts and blood as it prevents invasive procedures.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09459-5.

Patent ductus arteriosus in a late preterm neonate: think congenital hypopituitarism

A late preterm female neonate presented with initial respiratory distress and heart murmur attributed to a haemodynamically significant patent ductus arteriosus (hsPDA) not responding to two courses of ibuprofen. Thyroid function performed for prolonged neonatal jaundice at 3 weeks of life suggested central hypothyroidism. Subsequent adrenocorticotropic hormone stimulation test showing hypocortisolism and MRI revealing adenohypophysis hypoplasia confirmed the diagnosis of congenital hypopituitarism (CH). Commencement of hydrocortisone followed by thyroxine replacement coincided with clinical closure of the hsPDA within 72 hours of treatment. Hypothyroidism and hypocortisolism may have contributed to persistent hsPDA. Thyroid hormone increases cytochrome P450 activity, endothelin-1 and fibronectin expression. Hydrocortisone decreases sensitivity of ductus arteriosus to PGE2 These mechanisms have been postulated to cause ductal constriction and closure. Our case supports this association. hsPDA in a term and near-term neonate with a protracted disease course or associated midline defects should prompt the clinician to suspect CH (hypothyroidism and/or hypocortisolism).

Genetic mouse models of autism spectrum disorder present subtle heterogenous cardiac abnormalities

Autism spectrum disorder (ASD) and congenital heart disease (CHD) are linked on a functional and genetic level. Most work has investigated CHD‐related neurodevelopmental abnormalities. Cardiac abnormalities in ASD have been less studied. We investigated the prevalence of cardiac comorbidities relative to ASD genetic contributors. Using high frequency ultrasound imaging, we screened 9 ASD‐related genetic mouse models (Arid1b^(+/−), Chd8^(+/−), 16p11.2 (deletion), Sgsh^(+/−), Sgsh^(−/−), Shank3 Δexon 4–9^(+/−), Shank3 Δexon 4–9^(−/−), Fmr1^(−/−), Vps13b^(+/−)), and pooled wild‐type littermates (WTs). We measured heart rate (HR), aorta diameter (AoD), thickness and thickening of the left‐ventricular (LV) anterior and posterior walls, LV chamber diameter, fractional shortening, stroke volume and cardiac output, mitral inflow Peak E and A velocity ratio, ascending aorta velocity time integral (VTI). Mutant groups presented small‐scale alterations in cardiac structure and function compared to WTs (LV anterior wall thickness and thickening, chamber diameter and fractional shortening, HR). A greater number of significant differences was observed among mutant groups than between mutant groups and WTs. Mutant groups differed primarily in structural measures (LV chamber diameter and anterior wall thickness, HR, AoD). The mutant groups with most differences to WTs were 16p11.2 (deletion), Fmr1^(−/−), Arid1b^(+/−). The mutant groups with most differences from other mutant groups were 16p11.2 (deletion), Sgsh^(+/−), Fmr1^(−/−). Our results recapitulate the associated clinical findings. The characteristic ASD heterogeneity was recapitulated in the cardiac phenotype. The type of abnormal measures (morphological, functional) can highlight common underlying mechanisms. Clinically, knowledge of cardiac abnormalities in ASD can be essential as even non‐lethal abnormalities impact normal development.

Harnessing the Power of Stem Cell Models to Study Shared Genetic Variants in Congenital Heart Diseases and Neurodevelopmental Disorders

Advances in human pluripotent stem cell (hPSC) technology allow one to deconstruct the human body into specific disease-relevant cell types or create functional units representing various organs. hPSC-based models present a unique opportunity for the study of co-occurring disorders where “cause and effect” can be addressed. Poor neurodevelopmental outcomes have been reported in children with congenital heart diseases (CHD). Intuitively, abnormal cardiac function or surgical intervention may stunt the developing brain, leading to neurodevelopmental disorders (NDD). However, recent work has uncovered several genetic variants within genes associated with the development of both the heart and brain that could also explain this co-occurrence. Given the scalability of hPSCs, straightforward genetic modification, and established differentiation strategies, it is now possible to investigate both CHD and NDD as independent events. We will first overview the potential for shared genetics in both heart and brain development. We will then summarize methods to differentiate both cardiac & neural cells and organoids from hPSCs that represent the developmental process of the heart and forebrain. Finally, we will highlight strategies to rapidly screen several genetic variants together to uncover potential phenotypes and how therapeutic advances could be achieved by hPSC-based models.

[Cochlear implant and surgical intervention for CHARGE syndrome with laryngeal airway lesions]

Objective:To evaluate the clinical efficacy of surgical intervention for laryngeal airway lesions with concurrent cochlear implantation in CHARGE syndrome concomitant laryngeal airway lesions, and provide clinical data for cochlear implantation in children with CHARGE syndrome concomitant laryngeal airway lesions. Methods:The medical records of five cases diagnosed with CHARGE syndrome were retrospectively reviewed, two of them treated with surgical intervention for laryngeal airway lesions and concurrent cochlear implantation. One child treated with balloon dilatation of laryngeal stenosis and Cochlear implant, and another case received with modified supraglottoplasty for laryngeal malacia and Cochlear implant. Results:Two cases of CHARGE syndrome concomitant laryngeal airway disease, who underwent Cochlear implant and concurrent surgical intervention, recovered well after treatment. The remining three cases treated with Cochlear implant, who previously received deformity-correction surgery. All of the five cases presented with CHD7 mutation. Conclusion:Cochlear implant concurrent with surgical intervention of laryngeal airway lesions for the treatment of CHARGE syndrome concomitant laryngeal airway disease was safe and efficient, which could be a treatment option for children in this situation.

T-Cell Immunodeficiencies With Congenital Alterations of Thymic Development: Genes Implicated and Differential Immunological and Clinical Features

Combined Immunodeficiencies (CID) are rare congenital disorders characterized by defective T-cell development that may be associated with B- and NK-cell deficiency. They are usually due to alterations in genes expressed in hematopoietic precursors but in few cases, they are caused by impaired thymic development. Athymia was classically associated with DiGeorge Syndrome due to TBX1 gene haploinsufficiency. Other genes, implicated in thymic organogenesis include FOXN1, associated with Nude SCID syndrome, PAX1, associated with Otofaciocervical Syndrome type 2, and CHD7, one of the genes implicated in CHARGE syndrome. More recently, chromosome 2p11.2 microdeletion, causing FOXI3 haploinsufficiency, has been identified in 5 families with impaired thymus development. In this review, we will summarize the main genetic, clinical, and immunological features related to the abovementioned gene mutations. We will also focus on different therapeutic approaches to treat SCID in these patients.

CHARGE syndrome

The article provides literature data and description of the clinical case of CHARGE syndrome with an autosomal – dominant type of inheritance in a child of 3 years and 7 months. The name of the syndrome is formed by the first letters of the characteristic congenital malformations: “C” (coloboma) – optic disc coloboma, “H” (heart defects) – cardiovascular abnormalities, “A” (atresia of choanae) – atresia or stenosis of choan, “R” (retardation of growth and development) – growth deficit, developmental delay, “G” (genital anomalies) – genital anomalies, “E” (ear abnormalities and sensorineural hearing loss) – hearing organ abnormalities. A feature of the clinical case is the early diagnosis of CHARGE syndrome, manifested by bilateral optic disc coloboma; unilateral paresis of the facial nerve; congenital heart disease (open aortic duct); retardation of growth, psychomotor and psycho-speech development; cryptorchidism; bilateral anomaly of the outer ear (short, wide, absence of the lobe and external curl), sensorineural hearing loss; bilateral renal hypopalasia, chronic kidney disease.

The state of congenital heart disease

In this special issue of the American Journal of Medical Genetics Part C, we focus on the "State of Congenital Heart Disease." We anticipate that after viewing this journal, the reader will be up-to-date on the epidemiology of congenital heart disease (CHD), the genetic basis of CHD, ethical concerns, and the global impact of CHD. And most importantly, we are confident that this special issue conveys the message that CHD is complex and that much work is still needed in genetic and genomic research.