Rare and de novo variants in 827 congenital diaphragmatic hernia probands implicate LONP1 as candidate risk gene.

Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly that is often accompanied by other anomalies. Although the role of genetics in the pathogenesis of CDH has been established, only a small number of disease-associated genes have been identified. To further investigate the genetics of CDH, we analyzed de novo coding variants in 827 proband-parent trios and confirmed an overall significant enrichment of damaging de novo variants, especially in constrained genes. We identified LONP1 (lon peptidase 1, mitochondrial) and ALYREF (Aly/REF export factor) as candidate CDH-associated genes on the basis of de novo variants at a false discovery rate below 0.05. We also performed ultra-rare variant association analyses in 748 affected individuals and 11,220 ancestry-matched population control individuals and identified LONP1 as a risk gene contributing to CDH through both de novo and ultra-rare inherited largely heterozygous variants clustered in the core of the domains and segregating with CDH in affected familial individuals. Approximately 3% of our CDH cohort who are heterozygous with ultra-rare predicted damaging variants in LONP1 have a range of clinical phenotypes, including other anomalies in some individuals and higher mortality and requirement for extracorporeal membrane oxygenation. Mice with lung epithelium-specific deletion of Lonp1 die immediately after birth, most likely because of the observed severe reduction of lung growth, a known contributor to the high mortality in humans. Our findings of both de novo and inherited rare variants in the same gene may have implications in the design and analysis for other genetic studies of congenital anomalies.

Extracorporeal life support without systemic anticoagulation: a nitric oxide-based non-thrombogenic circuit for the artificial placenta in an ovine model.

BACKGROUND: Clinical translation of the extracorporeal artificial placenta (AP) is impeded by the high risk for intracranial hemorrhage in extremely premature newborns. The Nitric Oxide Surface Anticoagulation (NOSA) system is a novel non-thrombogenic extracorporeal circuit. This study aims to test the NOSA system in the AP without systemic anticoagulation. METHODS: Ten extremely premature lambs were delivered and connected to the AP. For the NOSA group, the circuit was coated with DBHD-N2O2/argatroban, 100 ppm nitric oxide was blended into the sweep gas, and no systemic anticoagulation was given. For the Heparin control group, a non-coated circuit was used and systemic anticoagulation was administered. RESULTS: Animals survived 6.8 ± 0.6 days with normal hemodynamics and gas exchange. Neither group had any hemorrhagic or thrombotic complications. ACT (194 ± 53 vs. 261 ± 86 s; p < 0.001) and aPTT (39 ± 7 vs. 69 ± 23 s; p < 0.001) were significantly lower in the NOSA group than the Heparin group. Platelet and leukocyte activation did not differ significantly from baseline in the NOSA group. Methemoglobin was 3.2 ± 1.1% in the NOSA group compared to 1.6 ± 0.6% in the Heparin group (p < 0.001). CONCLUSIONS: The AP with the NOSA system successfully supported extremely premature lambs for 7 days without significant bleeding or thrombosis. IMPACT: The Nitric Oxide Surface Anticoagulation (NOSA) system provides effective circuit-based anticoagulation in a fetal sheep model of the extracorporeal artificial placenta (AP) for 7 days. The NOSA system is the first non-thrombogenic circuit to consistently obviate the need for systemic anticoagulation in an extracorporeal circuit for up to 7 days. The NOSA system may allow the AP to be implemented clinically without systemic anticoagulation, thus greatly reducing the intracranial hemorrhage risk for extremely low gestational age newborns. The NOSA system could potentially be applied to any form of extracorporeal life support to reduce or avoid systemic anticoagulation.

The role of fetal hemoglobin in the artificial placenta: A premature ovine model.

INTRODUCTION: A radical paradigm shift in the treatment of premature infants failing conventional treatment is to recreate fetal physiology using an extracorporeal Artificial Placenta (AP). The aim of this study is to evaluate the effects of changing fetal hemoglobin percent (HbF%) on physiology and circuit function during AP support in an ovine model. METHODS: Extremely premature lambs (n = 5) were delivered by cesarean section at 117-121 d estimated gestational age (EGA) (term = 145d), weighing 2.5 ± 0.35 kg. Lambs were cannulated using 10-14Fr cannulae for drainage via the right jugular vein and reinfusion via the umbilical vein. Lambs were intubated and lungs were filled with perfluorodecalin to a meniscus with a pressure of 5-8 cm H2O. The first option for transfusion was fetal whole blood from twins followed by maternal red blood cells. Arterial blood gases were used to titrate AP support to maintain fetal blood gas values. RESULTS: The mean survival time on circuit was 119.6 ± 39.5 h. Hemodynamic parameters and lactate were stable throughout. As more adult blood transfusions were given to maintain hemoglobin at 10 mg/dL, the HbF% declined, reaching 40% by post operative day 7. The HbF% was inversely proportional to flow rates as higher flows were required to maintain adequate oxygen saturation and perfusion. CONCLUSIONS: Transfusion of adult blood led to decreased fetal hemoglobin concentration during AP support. The HbF% was inversely proportional to flow rates. Future directions include strategies to decrease the priming volume and establishing a fetal blood bank to have blood rich in HbF.

A single institution's experience with the management of peripheral bronchial atresia.

PURPOSE: Peripheral bronchial atresia is a pulmonary abnormality diagnosed on postnatal computed tomography after prenatal imaging reveals a congenital lung lesion. Debate regarding management of this abnormality prompted us to review our institution's practice patterns and outcomes. METHODS: All patients diagnosed with bronchial atresia were assessed from 6/2014 to 7/2020. Pediatric radiologists were surveyed to delineate computed tomography criteria used to diagnose peripheral bronchial atresia. Criteria were applied in an independent blinded review of postnatal imaging. Data for patients determined to have peripheral bronchial atresia and at least an initial pediatric surgical evaluation were analyzed. RESULTS: Twenty-eight patients with bronchial atresia received at least an initial pediatric surgical evaluation. Expectant management was planned for 22/28 (79%) patients. Two patients transitioned from an expectant management strategy to an operative strategy for recurrent respiratory infections; final pathology revealed bronchial atresia in both. Six patients were initially managed operatively; final pathology revealed bronchial atresia (n = 3) or congenital lobar overinflation (n = 3). CONCLUSIONS: Peripheral bronchial atresia can be safely managed expectantly. A change in symptoms is suspicious for alternate lung pathology, warranting further workup and consideration for resection. LEVEL OF EVIDENCE: Level IV.

Switching to centrifugal pumps may decrease hemolysis rates among pediatric ECMO patients.

Recent advances in ECLS technology have led to the adoption of centrifugal pumps for the majority of patients worldwide. Despite several advantages of centrifugal pumps, they remain controversial because a number of studies have shown increased rates of hemolysis. The aim of this study was to assess the impact of transitioning from roller to centrifugal pumps on hemolysis rates at our center. A retrospective analysis of all pediatric ECMO patients at a single center between 2005 and 2017 was undertaken. Hemolysis was defined as a plasma free hemoglobin >50 mg/dL. Multivariable logistic regression was performed correcting for several factors to determine risk factors for hemolysis and analyze outcomes among patients with hemolysis. Significant findings were those with p < 0.05. A total of 590 patients were identified during the study period. Multivariable logistic regression for risk factors for hemolysis showed roller pumps (OR 1.92, CI 1.11-3.33) and ECMO duration (OR 1.002 per hour, CI 1.00-1.01) to be significant factors. Rates of hemolysis significantly improved following conversion from roller to centrifugal pumps, with significantly lower rates of hemolysis in 2012, 2015, 2016, and 2017 when compared to the historical average with roller pumps from 2005 to 2009 (34.7%). Additionally, hemolysis was associated with an increased risk of death (OR 3.59, CI 2.05-6.29) when correcting for other factors. These data suggest decreasing rates of hemolysis with centrifugal pumps compared to roller pumps. Since hemolysis was also associated with increased risk of death, these data support the switch from roller to centrifugal pumps at ECMO centers.

De novo variants in congenital diaphragmatic hernia identify MYRF as a new syndrome and reveal genetic overlaps with other developmental disorders.

Congenital diaphragmatic hernia (CDH) is a severe birth defect that is often accompanied by other congenital anomalies. Previous exome sequencing studies for CDH have supported a role of de novo damaging variants but did not identify any recurrently mutated genes. To investigate further the genetics of CDH, we analyzed de novo coding variants in 362 proband-parent trios including 271 new trios reported in this study. We identified four unrelated individuals with damaging de novo variants in MYRF (P = 5.3x10(-8)), including one likely gene-disrupting (LGD) and three deleterious missense (D-mis) variants. Eight additional individuals with de novo LGD or missense variants were identified from our other genetic studies or from the literature. Common phenotypes of MYRF de novo variant carriers include CDH, congenital heart disease and genitourinary abnormalities, suggesting that it represents a novel syndrome. MYRF is a membrane associated transcriptional factor highly expressed in developing diaphragm and is depleted of LGD variants in the general population. All de novo missense variants aggregated in two functional protein domains. Analyzing the transcriptome of patient-derived diaphragm fibroblast cells suggest that disease associated variants abolish the transcription factor activity. Furthermore, we showed that the remaining genes with damaging variants in CDH significantly overlap with genes implicated in other developmental disorders. Gene expression patterns and patient phenotypes support pleiotropic effects of damaging variants in these genes on CDH and other developmental disorders. Finally, functional enrichment analysis implicates the disruption of regulation of gene expression, kinase activities, intra-cellular signaling, and cytoskeleton organization as pathogenic mechanisms in CDH.

Fetal Surgery in the Primate 4.0: A New Technique 30 Years Later.

INTRODUCTION: Open fetal surgery requires a hemostatic hysterotomy that minimizes membrane separation. For over 30 years, the standard of care for hysterotomy in the gravid uterus has been the AutoSuture Premium Poly CS*-57 stapler. OBJECTIVE: In this study, we sought to test the feasibility of hysterotomy in a rhesus monkey model with the Harmonic ACE®+7 Shears. METHODS: A gravid rhesus monkey underwent midgestation hysterotomy at approximately 90 days of gestation (2nd trimester; term = 165 ± 10 days) using the Harmonic ACE®+7 Shears. A two-layer uterine closure was completed and the dam was monitored by ultrasound intermittently throughout the pregnancy. At 58 days after hysterotomy (near term), a final surgery was performed to evaluate the uterus and hysterotomy site. RESULTS: A 3.5-cm hysterotomy was completed in 2 min 7 s. The opening was hemostatic and the membranes were sealed. Immediately after closure and throughout the pregnancy, ultrasound revealed intact membranes without separation and normal amniotic fluid levels. At term, the scar was well healed without signs of thinning or dehiscence. CONCLUSIONS: The Harmonic ACE®+7 Shears produced a hemostatic midgestation hysterotomy with membrane sealing in the rhesus monkey model. Importantly, healing was acceptable.

Likely damaging de novo variants in congenital diaphragmatic hernia patients are associated with worse clinical outcomes.

PURPOSE: Congenital diaphragmatic hernia (CDH) is associated with significant mortality and long-term morbidity in some but not all individuals. We hypothesize monogenic factors that cause CDH are likely to have pleiotropic effects and be associated with worse clinical outcomes. METHODS: We enrolled and prospectively followed 647 newborns with CDH and performed genomic sequencing on 462 trios to identify de novo variants. We grouped cases into those with and without likely damaging (LD) variants and systematically assessed CDH clinical outcomes between the genetic groups. RESULTS: Complex cases with additional congenital anomalies had higher mortality than isolated cases (P = 8 × 10-6). Isolated cases with LD variants had similar mortality to complex cases and much higher mortality than isolated cases without LD (P = 3 × 10-3). The trend was similar with pulmonary hypertension at 1 month. Cases with LD variants had an estimated 12-17 points lower scores on neurodevelopmental assessments at 2 years compared with cases without LD variants, and this difference is similar in isolated and complex cases. CONCLUSION: We found that the LD genetic variants are associated with higher mortality, worse pulmonary hypertension, and worse neurodevelopment outcomes compared with non-LD variants. Our results have important implications for prognosis, potential intervention and long-term follow up for children with CDH.

Calculating Observed-to-Expected Total Fetal Lung Volume in CDH Fetuses in Twin Gestation: Is There a Better Way?

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a potentially lethal birth defect, and identifying prenatal predictors of outcome is important. Observed-to-expected total fetal lung volume (o/e TFLV) has been shown to be a predictor of severity and useful in risk stratification but is variable due to different TFLV formulas. OBJECTIVES: To calculate o/e TFLV for CDH patients part of a twin gestation using the unaffected sibling as an internal control and comparing these values to those calculated using published formulas for TFLV. METHODS: Seven twin gestations with one fetus affected by CDH were identified between 2006 and 2017. The lung volume for each twin was calculated using magnetic resonance imaging (MRI), and o/e TFLV was calculated using the unaffected twin's TFLV. This percentage was then compared to the o/e TFLV calculated using published formulas. RESULTS: Lung volumes in the unaffected twins were within normal ranges at the lower end of the spectrum. No single TFLV formula was found to correlate perfectly. Intraclass correlation coefficient estimate was most consistent for o/e TFLV calculated with the Meyers formula and supported by Bland-Altman plots. CONCLUSIONS: O/e TFLV measured in CDH/non-CDH twin gestations using the unaffected sibling demonstrated agreement with o/e TFLV calculated using the Meyers formula. We urge the fetal community to standardize the method, use, and interpretation of fetal MRI in the prenatal evaluation of CDH.

Prenatal Dilated Rectum: Do We Need to Worry?

BACKGROUND: Advances in prenatal imaging is increasing detection of abnormally dilated bowel. There is no literature to date defining the criteria for a dilated rectum or its association with postnatal pathology. The aim of this study is to investigate the clinical significance of a prenatally identified dilated rectum. METHODS: A retrospective review was performed of all cases of "dilated bowel" on prenatal ultrasound between January 2000 and December 2017 at a single institution. We excluded ventral wall defects from review and sought to include only cases of a prominent or dilated rectum. Collected data included prenatal bowel measurements, postnatal diagnoses, need for surgical intervention, and outcomes. Descriptive statistics were applied. RESULTS: One hundred and ninety-three cases of prenatal "dilated bowel" were identified in which 12 (6.2%) had specifically visualized a prominent or dilated rectum. Nine of these (75.0%) had no rectal or intestinal abnormality on postnatal evaluation and were discharged feeding and defecating normally. The remaining three cases exhibited clinical pathology necessitating additional management: (1) meconium plug, (2) jejunal atresia with cecal perforation, and (3) rectal perforation with retroperitoneal abscess. All three had rectal biopsies with identification of ganglionated submucosa. CONCLUSIONS: Although a prenatal dilated rectum is a normal variant in the vast majority of cases, it may be associated with a gastrointestinal abnormality requiring surgical intervention. Interestingly, there were no cases of Hirschsprung's disease or anorectal malformations in this cohort. These results, in conjunction with continued efforts to identify and define rectal dilation, are useful for prenatal counseling and postnatal evaluation.

An Early Investigation into Possible Alternatives to Stapled Hysterotomy in Open Fetal Surgery.

PURPOSE: We hypothesized that surgical energy could be used to create hysterotomies in open fetal surgery. STUDY DESIGN: Initial studies compared the LigaSure Impact and Harmonic ACE + 7 Shears in the efficiency of hysterotomy and thermal damage. Pregnant ewes at an estimated gestational age (EGA) of 116 to 120 days (term = 145; n = 7) underwent hysterotomy using either device. Hysterotomy edges were resected, and thermal injury extent was determined by histopathological assessment. Upon determining a superior device, subsequent studies compared this to the AutoSuture Premium Poly CS*-57 Stapler in uterine healing. Pregnant ewes (n = 6) at an EGA of 87 to 93 days underwent 6-cm hysterotomy in each gravid horn with either the stapler (n = 5) or Harmonic (n = 5) followed by closure and animal recovery. After 37 to 42 days, uterine healing was assessed by evaluating tensile strength and histopathology. RESULTS: Thermal damage was more extensive with the LigaSure (n = 11 hysterotomies) than with the Harmonic (n = 11; 5.6 ± 1 vs. 3.1 ± 0.6 mm; p < 0.0001);therefore, the Harmonic was selected for healing studies. Gross scar appearance and tensile strength were the same between the Harmonic and stapler. The stapler caused more fibrosis (4/7 samples with "moderate" fibrosis vs. 0/8 with the Harmonic; p = 0.02). CONCLUSION: The Harmonic ACE + 7 caused less thermal injury than the LigaSure Impact and performed similar to the CS*-57 Stapler in uterine healing with continued gestation.

Outcomes of fetuses with primary hydrothorax that undergo prenatal intervention (prenatal intervention for hydrothorax).

BACKGROUND: Primary hydrothorax is a congenital anomaly affecting 1 in 10,000-15,000 pregnancies. The natural history of this condition is variable with some fetuses having spontaneous resolution and others showing progression. The associated pulmonary hypoplasia leads to increased perinatal morbidity and mortality. Optimal prenatal intervention remains controversial. METHODS: After obtaining the Institutional Review Board approval, a retrospective review of all patients evaluated for a fetal pleural effusion in the Fetal Diagnosis and Treatment Center at The University of Michigan, between 2006 and 2016 was performed. Cases with secondary etiologies for an effusion or when families decided to pursue elective termination were excluded. RESULTS: Pleural effusions were identified in 175 patients. Primary hydrothorax was diagnosed in 15 patients (8%). The effusions were bilateral in 13/15 cases (86%) and 10/15 (66%) had hydrops at presentation. All 15 patients with primary hydrothorax underwent prenatal intervention. Thoracentesis was performed in 14/15 cases (93%). Shunt placement was performed in 10/15 cases (66%). Shunt migration was seen in four patients (40%) and all of these underwent prenatal shunt replacement. Overall survival was 76%. The rates of prematurity and preterm premature rupture of membranes were 69% and 35%, respectively. CONCLUSIONS: Fetal intervention for the treatment of primary hydrothorax is effective, and it appears to confer a survival advantage. Both the fetuses and the mothers tolerated the procedures well. Preterm labor and preterm premature rupture of membranes remain an unsolved problem. Further studies are needed to understand the mechanisms behind the development of fetal hydrothorax.

Early Delivery of Sacrococcygeal Teratoma with Intraspinal Extension.

Sacrococcygeal teratoma (SCT) with intraspinal extension is rare. There is a risk of paraplegia associated with prolonged spinal cord compression. We present the case of an infant with a prenatal diagnosis of an SCT with a large intraspinal component that was causing compression of the lower spinal cord. Ultrasound at 33 weeks showed bilateral lower extremity and foot movement without hydrops or cardiac failure. Multidisciplinary decision was made to administer betamethasone and proceed with Cesarean delivery at 34 weeks. A vigorous live-born female was delivered and a multilevel laminectomy was performed at day of life 4. The pelvic resection was performed at 4 months. Pathology revealed mature teratoma. She had an uncomplicated postoperative course, is ambulatory, continent of stool, and has no evidence of recurrence. We conclude that intraspinal extension of SCT should be evaluated prenatally with ultrasound and fetal MRI. If there is concern for spinal cord compression, early delivery and urgent decompressive laminectomy may diminish the neurologic sequelae of prolonged spinal cord compression. Since these cases are rare, risks of prematurity need to be weighed against the neurologic risks. These infants should be treated with a multidisciplinary approach.

Increased burden of de novo predicted deleterious variants in complex congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) is a serious birth defect that accounts for 8% of all major birth anomalies. Approximately 40% of cases occur in association with other anomalies. As sporadic complex CDH likely has a significant impact on reproductive fitness, we hypothesized that de novo variants would account for the etiology in a significant fraction of cases. We performed exome sequencing in 39 CDH trios and compared the frequency of de novo variants with 787 unaffected controls from the Simons Simplex Collection. We found no significant difference in overall frequency of de novo variants between cases and controls. However, among genes that are highly expressed during diaphragm development, there was a significant burden of likely gene disrupting (LGD) and predicted deleterious missense variants in cases (fold enrichment = 3.2, P-value = 0.003), and these genes are more likely to be haploinsufficient (P-value = 0.01) than the ones with benign missense or synonymous de novo variants in cases. After accounting for the frequency of de novo variants in the control population, we estimate that 15% of sporadic complex CDH patients are attributable to de novo LGD or deleterious missense variants. We identified several genes with predicted deleterious de novo variants that fall into common categories of genes related to transcription factors and cell migration that we believe are related to the pathogenesis of CDH. These data provide supportive evidence for novel genes in the pathogenesis of CDH associated with other anomalies and suggest that de novo variants play a significant role in complex CDH cases.

A definition of gentle ventilation in congenital diaphragmatic hernia: a survey of neonatologists and pediatric surgeons.

Ventilation practices have changed significantly since the initial reports in the mid 1980 of successful use of permissive hypercapnia and spontaneous ventilation [often called gentle ventilation (GV)] in infants with congenital diaphragmatic hernia (CDH). However, there has been little standardization of these practices or of the physiologic limits that define GV. We sought to ascertain among Diaphragmatic Hernia Research and Exploration; Advancing Molecular Science (DHREAMS) centers' GV practices in the neonatal management of CDH. Pediatric surgeons and neonatologists from DHREAMS centers completed an online survey on GV practices in infants with CDH. The survey gathered data on how individuals defined GV including ventilator settings, blood gas parameters and other factors of respiratory management. A total of 87 respondents, from 12 DHREAMS centers completed the survey for an individual response rate of 53% and a 92% center response rate. Approximately 99% of the respondents defined GV as accepting higher carbon dioxide (PCO2) and 60% of the respondents also defined GV as accepting a lower pH. There was less consensus about the use of sedation and neuromuscular blocking agents in GV, both within and across the centers. Acceptable pH and PCO2 levels are broader than the goal ranges. Despite a lack of formal standardization, the results suggest that GV practice is consistently defined as the use of permissive hypercapnia with mild respiratory acidosis and less consistently with the use of sedation and neuromuscular blocking agents. GV is the reported practice of surveyed neonatologists and pediatric surgeons in the respiratory management of infants with CDH.

Hepatoduodenal ligament teratoma with immature elements.

Pediatric germ cell tumors comprise 1-3% of all malignant pediatric tumors and are found in variable locations. We present the case of a term 3.7 kg neonate who was found to have a giant liver mass at birth, later determined to be an immature teratoma arising from the hepatoduodenal ligament. This case report and images add to the limited literature a very rare presentation of a teratoma.

Novel Application of Laparoscopic Ultrasound for Fetoscopic Laser Ablation in Twin-Twin Transfusion Syndrome with Complete Anterior Placenta.

Fetoscopic laser coagulation of the placental communicating vessels has become the standard treatment for monochorionic/diamniotic twin pregnancies complicated by severe twin-twin transfusion syndrome. Fetoscopic trocar placement can be performed with transabdominal ultrasound guidance with a posterior placenta and most anterior placentas that have a safe avascular window for entry. However, trocar insertion is challenging in cases of a complete anterior placenta without an avascular window. Current techniques to deal with this situation include mini-laparotomy with exteriorization to allow for dorsal entry, percutaneous lateral entry under transabdominal ultrasound/Doppler guidance, and laparoscopic assisted access with direct visualization of trocar entry. We describe a modified technique of laparoscopic assisted fetoscopic trocar placement using a laparoscopic ultrasound probe, which allows for precise, real-time guidance of trocar placement.

Surveillance of fetal lung lesions using the congenital pulmonary airway malformation volume ratio: natural history and outcomes.

OBJECTIVES: The congenital pulmonary airway malformation volume ratio (CVR) is a widely used sonographic measure of relative mass size in fetuses with lung malformations. The purposes of this study were to examine serial CVR measurements to understand longitudinal growth patterns and to determine correlation with postnatal imaging. METHODS: An institutional review board-approved retrospective review was performed on fetuses referred for an echogenic lung malformation between 2002 and 2014. For each fetus, the CVR was prospectively calculated using 2D ultrasound and followed with advancing gestation. RESULTS: Based on 40 fetuses, the mean initial CVR was 0.51 ± 0.07 at 20.5 ± 0.3 weeks of gestation. The CVR increased after 24 weeks of gestation (p = 0.0014), peaking at a CVR of 0.96 ± 0.11 at 25.5 ± 0.05 weeks, followed by a significant decrease in the CVR to 0.43 ± 0.07 prior to term (p < 0.0001). However, approximately one third showed no appreciable increase in size. The mean CVR was significantly correlated with postnatal chest computed tomography (CT) size dimensions (p = 0.0032) and likelihood for lung resection (p = 0.0055). CONCLUSIONS: Fetal lung malformations tend to follow one of two distinct growth patterns, characterized by either (1) a maximal CVR between 25 and 26 weeks of gestation or (2) minimal change in relative growth. The mean CVR correlates with postnatal CT size and operative management.

Effect of Perflubron-induced lung growth on pulmonary vascular remodeling in congenital diaphragmatic hernia.

PURPOSE: Congenital diaphragmatic hernia (CDH) involves lung hypoplasia and pulmonary hypertension (PH). Post-natal Perflubron ventilation induces lung growth. This phenomenon is called Perflubon-induced lung growth (PILG). However, it does not appear to ameliorate PH in CDH. We aim to determine the effect of PILG on pulmonary vascular remodeling in neonates with CDH and PH requiring extracorporeal membrane oxygenation (ECMO). METHODS: Lung tissue from four patients was obtained, three treated with PILG + ECMO, and one maintained on conventional ventilation + ECMO (control). The distribution of collagen was assessed with Masson's trichrome stain. Immunohistochemistry was done to assess cell proliferation and immunofluorescence to assess vascular morphology. RESULTS: Comparing PILG vs. control, there was an increase in vessel wall diameter (6.85 µm, 10.28 µm, and 10.35 µm vs. 4.34 µm), increase in collagen thickness in two PILG patients (35.66 µm, 14.23 µm, and 38.46 µm vs. 22.16 µm), and decrease in lumen diameter despite similar total area (48.99 µm, 41.74 µm, and 36.32 µm vs. 51.56 µm) for each PILG patient vs. the control patient, respectively. CONCLUSION: PILG does not appear to improve pulmonary vascular remodeling that occurs with PH. The findings are descriptive and will require larger samples to validate the significance of the findings. Overall, further studies will be required to identify the mechanistic causes of PH in CDH to create effective treatments.

Whole exome sequencing identifies de novo mutations in GATA6 associated with congenital diaphragmatic hernia.

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a common birth defect affecting 1 in 3000 births. It is characterised by herniation of abdominal viscera through an incompletely formed diaphragm. Although chromosomal anomalies and mutations in several genes have been implicated, the cause for most patients is unknown. METHODS: We used whole exome sequencing in two families with CDH and congenital heart disease, and identified mutations in GATA6 in both. RESULTS: In the first family, we identified a de novo missense mutation (c.1366C>T, p.R456C) in a sporadic CDH patient with tetralogy of Fallot. In the second, a nonsense mutation (c.712G>T, p.G238*) was identified in two siblings with CDH and a large ventricular septal defect. The G238* mutation was inherited from their mother, who was clinically affected with congenital absence of the pericardium, patent ductus arteriosus and intestinal malrotation. Deep sequencing of blood and saliva-derived DNA from the mother suggested somatic mosaicism as an explanation for her milder phenotype, with only approximately 15% mutant alleles. To determine the frequency of GATA6 mutations in CDH, we sequenced the gene in 378 patients with CDH. We identified one additional de novo mutation (c.1071delG, p.V358Cfs34*). CONCLUSIONS: Mutations in GATA6 have been previously associated with pancreatic agenesis and congenital heart disease. We conclude that, in addition to the heart and the pancreas, GATA6 is involved in development of two additional organs, the diaphragm and the pericardium. In addition, we have shown that de novo mutations can contribute to the development of CDH, a common birth defect.