Genetic considerations in recurrent congenital diaphragmatic hernia in two siblings

Endothelial-to-Mesenchymal Transition in Human and Murine Models of Congenital Diaphragmatic Hernia

INTRODUCTION

Congenital diaphragmatic hernia (CDH) is a complex congenital disorder, characterized by pulmonary hypertension (PH) and hypoplasia. PH secondary to CDH (CDH-PH) features devastating morbidity and mortality (25-30%) among neonates. An unmet need is determining mechanisms triggering CDH-PH to save infants. Prior data suggest abnormal remodeling of the pulmonary vascular extracellular matrix (ECM), presumed to be driven by endothelial-to-mesenchymal transition (EndoMT), hinders postnatal vasodilation and limits anti-PH therapy in CDH. There are limited data on the role of EndoMT in CDH-PH.

METHODS

The purpose of the study was to investigate how EndoMT contributes to CDH-PH by identifying cells undergoing EndoMT noted by alpha smooth muscle actin (α-SMA) expression in human umbilical vein endothelial cells (HUVECs) and lung tissue obtained from murine pups using the nitrofen model. N = 8 CDH, N = 8 control HUVECs were stained for α-SMA and CD31 after being exposed for 24 h to TGFB, a known EndoMT promoter. N = 8 nitrofen, N = 8 control murine pup lungs were also stained for α-SMA and CD31. α-SMA and CD31 expression was quantified in HUVECs and murine tissue using Fiji imaging software and normalized to the total number of cells per slide noted by DAPI staining.

RESULTS

CDH HUVECs demonstrated a 1.1-fold increase in α-SMA expression (p = 0.02). The murine model did not show statistical significance between nitrofen and control pup lungs; however, there was a 0.4-fold increase in α-SMA expression with a 0.8-fold decrease in CD31 expression in the nitrofen pup lungs when compared to controls.

CONCLUSION

These results suggest that EndoMT could potentially play a role in the ECM remodeling seen in CDH-PH.

What should we tell parents? Congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is characterized by a defect in the muscle dividing the thoracic and abdominal cavities. This leads to herniation of the abdominal organs into the thorax and a disturbance of lung development. Two-thirds of cases are identified by prenatal ultrasound in the second trimester, which should prompt referral to a tertiary center for prognosis assessment and counseling by a multidisciplinary team familiar with this condition. In this review, we summarize evidence on prenatal diagnosis and postnatal management of CDH. There is a focus on information that should be provided to expecting parents during prenatal counseling.

Familial severe congenital diaphragmatic hernia: left herniation in one sibling and bilateral herniation in another

Familial congenital diaphragmatic hernia (CDH) is extremely rare; it comprises about 2% of all CDH cases. The empirical risk is about 2%, increasing to 10% in a family with two affected children. This report describes severe CDH in two siblings who had been diagnosed prenatally. The female newborn diagnosed with left CDH prenatally was born at 38 weeks of gestation. Despite surgical repair and intensive treatment, she died 10 days after birth. Her younger brother was born at 39 weeks of gestation after being diagnosed with bilateral CDH prenatally, and died 75 min after birth. Both infants had neither other congenital anomaly nor chromosomal abnormalities. Their parents are healthy without consanguinity. Their first daughter and the fourth child have no congenital anomalies.

Fryns syndrome a presentation of two siblings with congenital diaphragmatic hernia

INTRODUCTION

Congenital diaphragmatic hernia (CDH) is a congenital malformation that has a reported incidence ranging from 2.4 to 4.1 in 10,000 births. Despite advances in neonatal care, a mortality rate of 33% is still reported with isolated CDH, predominantly due to hypoxic respiratory failure secondary to pulmonary hypoplasia. Fryns syndrome is the most common autosomal recessive syndrome associated with CDH, reported in up to 10% of patients with CDH, comprising CDH, pulmonary hypoplasia, craniofacial abnormalities, distal limb hypoplasia and internal malformations.

CASE PRESENTATION

We present two siblings with lethal CDH born within a 30 month period. The clinical course in these two infants is described and the possible mode of inheritance for CDH in this family is reviewed.

CONCLUSION

In spite of lacking many advanced chromosomal evaluations in our institute we recommended for further investigation into isolated and particularly familial cases may lead to the identification of genetic abnormalities detectable with FISH assay, locus-specific DNA probes, or other new techniques. There remains an ongoing need for careful clinical review and blood banking of cases of CDH to allow better insight into the genetic causes of severe fetal anomalies such as CDH.