The Genomics of Congenital Diaphragmatic Hernia: A 10-Year Retrospective Review

Observed/Expected Lung-To-Head Ratio and Total Lung Volumes That Identify Fetuses With Severe Congenital Diaphragmatic Hernia in a North American Fetal Center

OBJECTIVE

To define the ultrasound observed/expected lung-to-head ratio (O/E LHR) and magnetic resonance imaging (MRI) observed/expected total lung volume (O/E TLV) cut-offs associated with survival and lack of extracorporeal membrane oxygenation (ECMO) utilization to determine the most severe cohort that may benefit from fetal intervention.

METHODS

Retrospective review of patients with a prenatal diagnosis of isolated left or right congenital diaphragmatic hernia (L CDH, R CDH) seen and delivered at our level III fetal center from January 2013-July 2023. Data were extracted from our clinical outcome database. Characteristics of survivors and non-survivors were compared for both the L CDH and R CDH groups. For both O/E LHR and O/E TLV, the Youden criteria were then used to determine a good sensitivity and specificity for predicting survival and ECMO utilization for L and R CDH, respectively, in Receiver Operator Characteristic (ROC) curve analysis.

RESULTS

340 patients were included in the study, including 283 (83.2%) with L CDH and 57 (16.8%) with R CDH. The median [interquartile range, IQR] O/E LHR for L and R CDH was 37.9 [28.7-47.3] and 49.0 [40.0-64.5], respectively. The median O/E TLV for L and R CDH was 36.0 [28.0-48.0] and 25.3 [23.6-29.8], respectively. For survival, an O/E LHR of 28.1% and O/E TLV of 34.0% and an O/E LHR of 46.8% and O/E TLV of 17.6% were the best cut-offs for L and R CDH, respectively. For ECMO utilization, an O/E LHR of 32.8% and O/E TLV of 35.3% and an O/E LHR of 47.0% and O/E TLV of 22.0% were the best cut-offs for L and R CDH, respectively.

CONCLUSION

We report the best ultrasound O/E LHR and MRI TLV cut-offs associated with survival and lack of ECMO utilization in our cohort.

Update on Management and Outcomes of Congenital Diaphragmatic Hernia

Infants with congenital diaphragmatic hernia (CDH) benefit from comprehensive multidisciplinary teams that have experience in caring for the unique and complex issues associated with CDH. Despite prenatal referral to specialized high-volume centers, advanced ventilation strategies and pulmonary hypertension management, and extracorporeal membrane oxygenation, mortality and morbidity remain high. These infants have unique and complex issues that begin in fetal and infant life, but persist through adulthood. Here we will review the literature and share our clinical care pathway for neonatal care and follow up. While many advances have occurred in the past few decades, our work is just beginning to continue to improve the mortality, but also importantly the morbidity of CDH.

Common variants increase risk for congenital diaphragmatic hernia within the context of de novo variants

Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly often accompanied by other structural anomalies and/or neurobehavioral manifestations. Rare de novo protein-coding variants and copy-number variations contribute to CDH in the population. However, most individuals with CDH remain genetically undiagnosed. Here, we perform integrated de novo and common-variant analyses using 1,469 CDH individuals, including 1,064 child-parent trios and 6,133 ancestry-matched, unaffected controls for the genome-wide association study. We identify candidate CDH variants in 15 genes, including eight novel genes, through deleterious de novo variants. We further identify two genomic loci contributing to CDH risk through common variants with similar effect sizes among Europeans and Latinx. Both loci are in putative transcriptional regulatory regions of developmental patterning genes. Estimated heritability in common variants is ∼19%. Strikingly, there is no significant difference in estimated polygenic risk scores between isolated and complex CDH or between individuals harboring deleterious de novo variants and individuals without these variants. The data support a polygenic model as part of the CDH genetic architecture.

Delivery Room Management of Infants with Surgical Conditions

Delivery room resuscitation of infants with surgical conditions can be complex and depends on an experienced and cohesive multidisciplinary team whose performance is more important than that of any individual team member. Existing resuscitation algorithms were not developed for infants with congenital anomalies, and delivery room resuscitation is largely dictated by expert opinion extrapolating physiologic expectations from infants without anomalies. As prenatal diagnosis rates improve, there is an increased ability to plan for the unique delivery room needs of infants with surgical conditions. In this review, we share expert opinion, including our center's delivery room management for neonatal noncardiac surgical conditions, and highlight knowledge gaps and the need for further studies and evidence-based practice to be incorporated into the delivery room care of infants with surgical conditions. Future research in this area is essential to move from an expert-based approach to a data-driven approach to improve and individualize delivery room resuscitation of infants with surgical conditions.

Further evidence that the neurodevelopmental gene FBXW7 predisposes to Wilms tumor

Somatic variants in the NOTCH pathway regulator FBXW7 are frequently seen in a variety of malignancies. Heterozygous loss-of-function germline variants in FBXW7 have recently been described as causative for a neurodevelopmental syndrome. Independently, FBXW7 was also considered as a susceptibility gene for Wilms tumor due to a few observations of heterozygous germline variants in patients with Wilms tumor. Whether the same FBXW7 variants are implicated in both, neurodevelopmental delay and Wilms tumor formation, remained unclear. By clinical testing, we now observed a patient with neurodevelopmental delay due to a de novo constitutional mosaic FBXW7 splice site pathogenic variant who developed Wilms tumor. In the tumor, we identified a second hit frameshift variant in FBXW7. Immunohistochemical staining was consistent with mosaic loss of FBXW7 protein expression in the tumor. Our data support the role of constitutional FBXW7 pathogenic variants in both, neurodevelopmental disorder and the etiology of Wilms tumor. Therefore, Wilms tumor screening should be considered in individuals with constitutional or germline pathogenic variants in FBXW7 and associated neurodevelopmental syndrome.

Diagnosis and management of congenital diaphragmatic hernia: a 2023 update from the Canadian Congenital Diaphragmatic Hernia Collaborative

OBJECTIVE

The Canadian Congenital Diaphragmatic Hernia (CDH) Collaborative sought to make its existing clinical practice guideline, published in 2018, into a 'living document'.

DESIGN AND MAIN OUTCOME MEASURES

Critical appraisal of CDH literature adhering to Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Evidence accumulated between 1 January 2017 and 30 August 2022 was analysed to inform changes to existing or the development of new CDH care recommendations. Strength of consensus was also determined using a modified Delphi process among national experts in the field.

RESULTS

Of the 3868 articles retrieved in our search that covered the 15 areas of CDH care, 459 underwent full-text review. Ultimately, 103 articles were used to inform 20 changes to existing recommendations, which included aspects related to prenatal diagnosis, echocardiographic evaluation, pulmonary hypertension management, surgical readiness criteria, the type of surgical repair and long-term health surveillance. Fifteen new CDH care recommendations were also created using this evidence, with most related to the management of pain and the provision of analgesia and neuromuscular blockade for patients with CDH.

CONCLUSIONS

The 2023 Canadian CDH Collaborative's clinical practice guideline update provides a management framework for infants and children with CDH based on the best available evidence and expert consensus.

Effects of 1.5-T versus 3-T magnetic resonance imaging in fetuses: is there a difference in postnatal neurodevelopmental outcome? Evaluation in a fetal population with left-sided congenital diaphragmatic hernia

BACKGROUND

The utilization of 3-T magnetic field strength in obstetric imaging is increasingly common. It is important to ensure that magnetic resonance (MR) imaging with higher magnetic field strength is safe for the fetus. Comparison of neurodevelopmental outcome in neonates undergoing prenatal MR imaging with 1.5-T versus 3-T is of interest but has not yet been examined.

OBJECTIVE

We hypothesized no clinically meaningful difference in neurodevelopmental outcome between fetuses undergoing 1.5-T versus 3-T fetal MR imaging. As imaging a normal fetus for research purposes is illegal in Pennsylvania, this study was conducted in a population of fetuses with left congenital diaphragmatic hernia (left-CDH).

MATERIALS AND METHODS

A retrospective review of neurodevelopmental outcome of fetuses with left-CDH scanned at 1.5-T (n=75) versus 3-T (n=25) magnetic field strength between July of 2012 and December of 2019 was performed. Neurodevelopmental outcomes were assessed using the Bayley Scales of Infant Development, 3rd Edition (BSID-III).

RESULTS

There were no statistical differences in median age of assessment (1.5-T: 18 [12, 25] versus 3-T: 21 [11, 26], P=0.79), in mean BSID-III cognitive (1.5-T: 91 ± 14 versus 3-T: 90 ± 16, P=0.82), language (1.5-T: 92 ± 20 versus 3-T: 91 ± 20, P=0.91), and motor composite (1.5-T: 89 ± 15 versus 3-T: 87 ± 18, P=0.59) scores, subscales scores (for all, P>0.50), or in risk of abnormal neuromuscular exam (P=0.29) between neonates with left-CDH undergoing a 1.5-T versus 3-T MR imaging during fetal life. Additionally, the distribution of patients with average, mildly delayed, and severely delayed BSID-III scores was similar between the two groups (for all, P>0.50). The overall distribution of the composite scores in this CDH population was similar to the general population independent of exposure to 1.5-T or 3-T fetal MR imaging. Two 3-T patients (8%) and five 1.5-T patients (7%) scored within the significant delayed range for all BSID-III domains. Subjects with lower observed-to-expected fetal lung volume (O/E FLV) and postnatal need for ECMO had lower cognitive, language, motor, and subscales scores (for all, P<0.03) regardless of being imaged at 1.5-T versus 3-T.

CONCLUSION

This preliminary study suggests that, compared to 1.5-T MR imaging, fetal exposure to 3-T MR imaging does not increase the risk of neurodevelopmental impairment in fetuses with left-CDH. Additional MR imaging studies in larger CDH cohorts and other fetal populations are needed to replicate and extend the present findings.

Identifying phenotypic expansions for congenital diaphragmatic hernia plus (CDH+) using DECIPHER data

Congenital diaphragmatic hernia (CDH) can occur in isolation or in conjunction with other birth defects (CDH+). A molecular etiology can only be identified in a subset of CDH cases. This is due, in part, to an incomplete understanding of the genes that contribute to diaphragm development. Here, we used clinical and molecular data from 36 individuals with CDH+ who are cataloged in the DECIPHER database to identify genes that may play a role in diaphragm development and to discover new phenotypic expansions. Among this group, we identified individuals who carried putatively deleterious sequence or copy number variants affecting CREBBP, SMARCA4, UBA2, and USP9X. The role of these genes in diaphragm development was supported by their expression in the developing mouse diaphragm, their similarity to known CDH genes using data from a previously published and validated machine learning algorithm, and/or the presence of CDH in other individuals with their associated genetic disorders. Our results demonstrate how data from DECIPHER, and other public databases, can be used to identify new phenotypic expansions and suggest that CREBBP, SMARCA4, UBA2, and USP9X play a role in diaphragm development.

Evidence for an association between Coffin-Siris syndrome and congenital diaphragmatic hernia

Coffin-Siris syndrome (CSS) is an autosomal dominant neurodevelopmental syndrome that can present with a variety of structural birth defects. Pathogenic variants in 12 genes have been shown to cause CSS. Most of these genes encode proteins that are a part of the mammalian switch/sucrose non-fermentable (mSWI/SNF; BAF) complex. An association between genes that cause CSS and congenital diaphragmatic hernia (CDH) has been suggested based on case reports and the analysis of CSS and CDH cohorts. Here, we describe an unpublished individual with CSS and CDH, and we report additional clinical information on four published cases. Data from these individuals, and a review of the literature, provide evidence that deleterious variants in ARID1B, ARID1A, SMARCB1, SMARCA4, SMARCE1, ARID2, DPF2, and SMARCC2, which are associated with CSS types 1-8, respectively, are associated with the development of CDH. This suggests that additional genetic testing to identify a separate cause of CDH in an individual with CSS may be unwarranted, and that comprehensive genetic testing for individuals with non-isolated CDH should include an evaluation of CSS-related genes. These data also suggest that the mSWI/SNF (BAF) complex may play an important role in diaphragm development.