The etiology of congenital diaphragmatic hernia: still largely unknown?

[Congenital diaphragmatic hernia : Imaging-from diagnosis to aftercare]

STANDARD RADIOLOGICAL METHODS

Fetal: Ultrasound and magnetic resonance imaging (MRI); postnatal: conventional X‑ray diagnostics, computed tomography (CT) and MRI.

METHODICAL INNOVATIONS

MRI-based lung ventilation and perfusion measurement.

PRACTICAL RECOMMENDATIONS

Lifelong follow-up care should be provided, in which radiology is part of the treatment team.

Radiomics-Assisted Computed Tomography-Based Analysis to Evaluate Lung Morphology Characteristics after Congenital Diaphragmatic Hernia

Purpose: Children with congenital diaphragmatic hernia suffer from long-term morbidity, including lung function impairment. Our study aims to analyze lung morphology characteristics via radiomic-assisted extraction of lung features in patients after congenital diaphragmatic hernia repair. Materials and Methods: 72 patients were retrospectively analyzed after approval by the local research ethics committee. All the image data were acquired using a third-generation dual-source CT (SOMATOM Force, Siemens Healthineers, Erlangen, Germany). Dedicated software was used for image analysis, segmentation, and processing. Results: Radiomics analysis of pediatric chest CTs of patients with status after CDH was possible. Between the ipsilateral (side of the defect) and contralateral lung, three shape features and two higher-order texture features were considered statistically significant. Contralateral lungs in patients with and without ECMO treatment showed significant differences in two shape features. Between the ipsilateral lungs in patients with and without the need for ECMO 1, a higher-order texture feature was depicted as statistically significant. Conclusions: By adding quantitative information to the visual assessment of the radiologist, radiomics-assisted feature analysis could become an additional tool in the future to assess the degree of lung hypoplasia in order to further improve the therapy and outcome of CDH patients.

Death by late presenting of diaphragmatic hernia in an infant: case report and review of the literature

Background

Congenital diaphragmatic hernia (CDH) is a congenital malformation of the diaphragm, resulting in the herniation of the abdominal organs into the thoracic cavity. If not properly diagnosed before or at birth, CDH represents a life-threatening pathology in infants and a major cause of death. We present a fatal case of congenital diaphragmatic hernia corresponding to Bochdalek hernia, discovered incidentally during a sudden death’s autopsy of an infant. To achieve a better view of the range of these anomalies, we also conducted a literature review on this subject describing the pathogenesis, manifestations, diagnosis, and autopsy contribution to addressing these CDH.

Case presentation

The case involved a 4-month-old female infant who presented sudden respiratory difficulties after breastfeeding. External examination found marked cyanosis with no evidence of trauma. Upon opening the chest cavity, the stomach, markedly distended, was occupying much of the left pleural cavity. The left lung was compressed and displaced superiorly, and the heart was also compressed and deviated to the right. This mediastinal deviation was due to an ascension of the stomach into the chest cavity through a 2 × 1.5 cm defect in the posterior left hemidiaphragm. Further examination remarked an ecchymotic appearance of the stomach portion entrapped in the hernia defect suggesting recent strangulation of the stomach. The lungs showed atelectasis with signs of pulmonary infection in the histology study.

Conclusions

CDH might be considered uncommon and not always mentioned in the list of sudden death in infant causes. Forensic pathologists should know of this malformation in order to apply the best autopsy techniques and thus allow positive feedback to pediatricians considering the possible legal implications.

Maternal dietary intake of vitamin A during pregnancy was inversely associated with congenital diaphragmatic hernia: the Japan Environment and Children's Study

The pathogenesis of congenital diaphragmatic hernia (CDH) is largely unknown; however, vitamin A seems to play a role in diaphragmatic development. Previous case-control studies reported that maternal dietary vitamin A intake was inversely associated with the risk of CDH. To our knowledge, however, there is no prospective evidence regarding this association. Our aim was to examine whether maternal intake of vitamin A was associated with CDH occurrence. Baseline data, from the Japan nationwide birth cohort study (2011-2014) of 89 658 mothers (mean age at delivery = 31·2 years) who delivered singleton live births, were analysed. We assessed dietary habits using an FFQ focused on the first trimester and estimated the daily intake of total vitamin A (retinol activity equivalents), retinol, provitamin A carotenoids and vegetables. The occurrence of CDH was ascertained from medical records. A total of forty cases of CDH were documented. The adjusted OR of CDH occurrence for the high total vitamin A intake category (median = 468 μg/d) was 0·6 (95 % CI 0·3, 1·2) with reference to the low intake category (230 μg/d). When we restricted to mothers with a prepregnancy BMI of 18·5-24·9 kg/m2, vitamin A intake was inversely associated with the risk of their children being born with CDH (OR 0·5, 95 % CI 0·2, 1·0). Even given the limited number of cases in the study, our findings provide additional evidence to link vitamin A with CDH.

Metabolic disturbances of the vitamin A pathway in human diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common life-threatening congenital anomaly resulting in high rates of perinatal death and neonatal respiratory distress. Some of the nonisolated forms are related to single-gene mutations or genomic rearrangements, but the genetics of the isolated forms (60% of cases) still remains a challenging issue. Retinoid signaling (RA) is critical for both diaphragm and lung development, and it has been hypothesized that subtle disruptions of this pathway could contribute to isolated CDH etiology. Here we used time series of normal and CDH lungs in humans, in nitrofen-exposed rats, and in surgically induced hernia in rabbits to perform a systematic transcriptional analysis of the RA pathway key components. The results point to CRPBP2, CY26B1, and ALDH1A2 as deregulated RA signaling genes in human CDH. Furthermore, the expression profile comparisons suggest that ALDH1A2 overexpression is not a primary event, but rather a consequence of the CDH-induced lung injury. Taken together, these data show that RA signaling disruption is part of CDH pathogenesis, and also that dysregulation of this pathway should be considered organ specifically.

Role of SOX2 in foregut development in relation to congenital abnormalities

The uptake of the two essential ingredients for life, oxygen and nutrients, occurs primarily through the oral cavity, but these two lifelines need to be separated with high accuracy once inside the body. The two systems, the gas exchange pulmonary system and the gastro-intestinal feeding system, are derived from the same primitive embryonic structure during development, the foregut, which need to be separated before birth. In certain newborns, this separation occurs not or insufficiently, leading to life threatening conditions, sometimes incompatible with life. The development of the foregut, trachea and lungs is influenced and coordinated by a multitude of signaling cascades and transcription factors. In this review, we will highlight the development of the foregut and pulmonary system and focus on associated congenital abnormalities in light of known genetic alterations with specific attention to the transcription factor SOX2.

Complex craniosynostosis is associated with the 2p15p16.1 microdeletion syndrome

In a screening project of patients with (complex) craniosynostosis using genomic arrays, we identified two patients with craniosynostosis and microcephaly with a deletion in the 2p15p16.1 chromosomal region. This region has been associated with a new microdeletion syndrome, for which patients have various features in common, including microcephaly and intellectual disability. Deletions were identified using Affymetrix 250K SNP array and further characterized by fluorescence in situ hybridization (FISH) analysis and qPCR. The deletions in our two patients overlapped within the 2p15p16.1 microdeletion syndrome area and were 6.8 and 6.9 Mb in size, respectively. FISH and qPCR confirmed the presence of only one copy in this region. Finemapping of the breakpoints indicated precise borders in our patients and were further finemapped in two other previously reported patients. Clinical features of patients with deletions in the 2p15p16.1 region vary. Including data from our patients, now eight out of nine reported patients have microcephaly, one of the major features, and all had intellectual disability. The current reported two patients add different forms of craniosynostosis to the clinical spectrum of this recently recognized microdeletion syndrome.

Lethal Bochdalek hernia in a three-year-old: pathological findings and medicolegal investigation in accusation of malpractice

Diaphragmatic hernias can be a pitfall for paediatric diagnostics, especially in the cases of late presentation, which can also have medico-legal ramifications as exposed. A three-year-old boy was taken to a children's hospital after an episode of abdominal pain and vomiting of food. A physical examination proved normal, with mild ketonuria being found and he was discharged. Three months later for the same signs and symptoms, he was taken once more to hospital, where he arrived in a state of cardiac arrest and died. A lawsuit was begun against the doctors who had examined him three months earlier. The autopsy found herniation of the abdominal organs into the left pleural cavity through a defect in the left hemidiaphragm. The cause of death was identified as cardiac tamponade caused by mechanical compression of multiple herniated abdominal organs. The histopathological examination revealed marked atelectasis of the left lung, with non-expansion of 60-90% of the alveoli which suggested an acute mechanism that proved fatal, and the doctors were acquitted. The features of this disease and the possible difficulties in its diagnosis highlight the need for the utmost attention in differential diagnosis, even at an age where the discovery of a diaphragmatic hernia is exceedingly rare.

A family-based paradigm to identify candidate chromosomal regions for isolated congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a developmental defect of the diaphragm that causes high newborn mortality. Isolated or non-syndromic CDH is considered a multifactorial disease, with strong evidence implicating genetic factors. As low heritability has been reported in isolated CDH, family-based genetic methods have yet to identify the genetic factors associated with the defect. Using the Utah Population Database, we identified distantly related patients from several extended families with a high incidence of isolated CDH. Using high-density genotyping, seven patients were analyzed by homozygosity exclusion rare allele mapping (HERAM) and phased haplotype sharing (HapShare), two methods we developed to map shared chromosome regions. Our patient cohort shared three regions not previously associated with CDH, that is, 2q11.2-q12.1, 4p13 and 7q11.2, and two regions previously involved in CDH, that is, 8p23.1 and 15q26.2. The latter regions contain GATA4 and NR2F2, two genes implicated in diaphragm formation in mice. Interestingly, three patients shared the 8p23.1 locus and one of them also harbored the 15q26.2 segment. No coding variants were identified in GATA4 or NR2F2, but a rare shared variant was found in intron 1 of GATA4. This work shows the role of heritability in isolated CDH. Our family-based strategy uncovers new chromosomal regions possibly associated with disease, and suggests that non-coding variants of GATA4 and NR2F2 may contribute to the development of isolated CDH. This approach could speed up the discovery of the genes and regulatory elements causing multifactorial diseases, such as isolated CDH.

Developmental and genetic aspects of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a frequent occurring cause of neonatal respiratory distress and occurs 1 in every 3,000 liveborns. Ventilatory support and pharmaceutical treatment of the co-occurring lung hypoplasia and pulmonary hypertension are insufficient in, respectively, 20% of isolated cases and 60% of complex ones leading to early perinatal death. The exact cause of CDH remains to be identified in the majority of human CDH patients and prognostic factors predicting treatment refraction are largely unknown. Their identification is hampered by the multifactorial and heterogenic nature of this congenital anomaly. However, application of high-resolution molecular cytogenetic techniques to patients' DNA now enables detection of chromosomal aberrations in 30% of the patients. Furthermore, recent insights in rodent embryogenesis pointed to a specific disruption of the early mesenchymal structures in the primordial diaphragm of CDH-induced offspring. Together, these data allowed for the introduction of new hypotheses on CDH pathogenesis, although many issues remain to be resolved. In this review, we have combined these new insights and remaining questions on diaphragm pathogenesis with a concise overview of the clinical, embryological, and genetic data available.

Congenital diaphragmatic hernia: still a moving target

The primary therapeutic target for congenital diaphragmatic hernia (CDH) patients has shifted from emergency surgical repair towards a non-operative emergency of the newborn treated by interdisciplinary teams. The increased understanding of the epidemiological and pathophysiological aspects of CDH have led to an improved knowledge and application of prenatal diagnosis, postnatal ventilation strategies, treatment of associated pulmonary hypertension and the role of extracorporeal membrane oxygenation therapy. In the surgical field, the perspectives have changed with delayed CDH repair, the introduction of minimally invasive surgery and use of prosthetic material for closure of large defects. With decreased mortality, long term multi-organ morbidity has increased in some survivors. In the near future, randomized controlled trials on different aspects of therapy will determine evidence-based optimal care.

[Congenital diaphragmatic hernia - mechanisms of pulmonary hypoplasia]

Congenital diaphragmatic hernia (CDH) is a common cause of severe neonatal respiratory distress. Mortality and morbidity are determined by the amount of pulmonary hypoplasia (PH) that occurs and by the development of therapy-resistant pulmonary hypertension. The pathogenesis and aetiology of CDH and its associated anomalies are still largely unknown despite all research efforts. The pathogenesis of CDH is based on an assumption linking herniation of abdominal viscera into the thorax with compression of the developing lung. PH, however, can also result from reduced distension of the developing lung secondary to impaired fetal breathing movements. Our understanding of CDH has also been aided by basic research with the use of dietary, teratogen-induced, and knockout models of CDH. These studies indicate that lung hypoplasia may involve disturbances of mitogenic signalling pathways fundamental to embryonic lung development. Recent data reveal the role of disruption of a retinoid-signalling pathway in the pathogenesis of CDH. Although multifactorial inheritance may best explain most cases of CDH in humans, much has been learned about the genetic factors that play a role in the development of CDH by studies of patients with CDH caused by specific genetic syndromes and chromosome anomalies. More research is warranted to improve our understanding of normal and abnormal lung development in relation to CDH. Such investigations will help in the design of new treatment strategies to improve the natural course or even to prevent this anomaly.

Comparable low-level mosaicism in affected and non affected tissue of a complex CDH patient

In this paper we present the detailed clinical and cytogenetic analysis of a prenatally detected complex Congenital Diaphragmatic Hernia (CDH) patient with a mosaic unbalanced translocation (5;12). High-resolution whole genome SNP array confirmed a low-level mosaicism (20%) in uncultured cells, underlining the value of array technology for identification studies. Subsequently, targeted Fluorescence In-Situ Hybridization in postmortem collected tissues demonstrated a similar low-level mosaicism, independently of the affected status of the tissue. Thus, a higher incidence of the genetic aberration in affected organs as lung and diaphragm cannot explain the severe phenotype of this complex CDH patient. Comparison with other described chromosome 5p and 12p anomalies indicated that half of the features presented in our patient (including the diaphragm defect) could be attributed to both chromosomal areas. In contrast, a few features such as the palpebral downslant, the broad nasal bridge, the micrognathia, microcephaly, abnormal dermatoglyphics and IUGR better fitted the 5p associated syndromes only. This study underlines the fact that low-level mosaicism can be associated with severe birth defects including CDH. The contribution of mosaicism to human diseases and specifically to congenital anomalies and spontaneous abortions becomes more and more accepted, although its phenotypic consequences are poorly described phenomena leading to counseling issues. Therefore, thorough follow-up of mosaic aberrations such as presented here is indicated in order to provide genetic counselors a more evidence based prediction of fetal prognosis in the future.

Genetics

For many years karyotyping has been a successful tool to identify chromosome aberrations in congenital malformations. It has proven to be a highly reliable technique for identifying numerical chromosome changes and structural chromosomal rearrangements, such as deletions, duplications, translocations, or inversions. However, karyotyping has limited resolution of 5-10 Mb and depends on the availability of metaphases. In the last decade, we have experienced the implementation of molecular cytogenetic techniques, resulting in the identification of chromosomal aberrations smaller than 5 Mbp. Because DNA is used as starting material also analysis of paraffin or frozen biopsies is possible. Several genes and loci have been identified, and careful genotype phenotype correlation has lead to the recognition of new syndromes. A further characterization of these new genes and loci involved in the etiology of congenital anomalies will lead to a better understanding of the underlying developmental pathways.