Incidence of alveolar capillary dysplasia in severe idiopathic persistent pulmonary hypertension of the newborn

Clinical Relevance of Rapid FOXF1-Targeted Sequencing in Patients Suspected of Alveolar Capillary Dysplasia With Misalignment of Pulmonary Veins

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a lethal congenital lung disorder that presents shortly after birth with respiratory failure and therapy-resistant pulmonary hypertension. It is associated with heterozygous point mutations and genomic deletions that involve the FOXF1 gene or its upstream regulatory region. Patients are unresponsive to the intensive treatment regimens and suffer unnecessarily because ACDMPV is not always timely recognized and histologic diagnosis is invasive and time consuming. Here, we demonstrate the usefulness of a noninvasive, fast genetic test for FOXF1 variants that we previously developed to rapidly diagnose ACDMPV and reduce the time of hospitalization.

Ultrasound findings in neonates with alveolar capillary dysplasia with misalignment of the pulmonary veins: report of two cases

Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACDMPV) is a rare congenital pulmonary disease that affects newborns. Most patients with ACDMPV are born at full term and are healthy. The main clinical manifestations are refractory pulmonary hypertension and pulmonary failure with gastrointestinal, urinary, or cardiac malformations. ACDMPV often progresses rapidly, but no conventional biological or imaging tests other than genetic testing are available for its diagnosis. Lung biopsy is currently the gold standard for diagnosis. We herein report two cases of ACDMPV confirmed by pathological examination and discuss their ultrasonographic findings.

Pulmonary alveolar capillary dysplasia in infants: A rare and deadly missed diagnosis

The pulmonary alveolocapillary dysplasia (ACD) with pulmonary vein misalignment (PVM) is a rare condition characterized by a congenital anomaly of the development of the pulmonary parenchyma. We present a case of an 8-month-old infant who died quickly from acute respiratory failure complicating an unknown ACD. We also describe its epidemiological characteristics in infants and we discuss the diagnosis's difficulties. In this case, a pulmonary arterial hypertension was decompensated by an infection. A medico-legal autopsy was performed. As for the Histological examination, it showed the features of ACD/PVM.

Histopathologic and Genetic Features of Alveolar Capillary Dysplasia with Atypical Late Presentation and Prolonged Survival

Alveolar capillary dysplasia typically presents with neonatal pulmonary hypertension and early mortality. However, there is growing evidence for a subset of disease with atypical late onset and/or prolonged survival. Here, we present the variable clinical, genetic, and pathology findings of 4 such patients.

[Clinicopathological analysis of pulmonary vascular disease in 38 neonates died of respiratory failure]

We reviewed the data of 38 neonates who died of respiratory failure. Paraffin sections of the autopsy lung samples were examined with HE staining or immunolabeling for CD34, CD68 and CK to observe the development of the pulmonary vessels and detect potential pulmonary vascular diseases (PVDs). Five cases were identified to have PVDs, including pulmonary hypertensive vascular remodeling in 3 cases and alveolar capillary dysplasia in 2 cases. The result indicated that PVD was one of the important reasons for respiratory failure in these neonates.

Pre-cannulation lung biopsy shortens ECMO course

We describe the clinical course of an infant with respiratory failure who underwent lung biopsy prior to cannulation for undergoing extracorporeal membrane oxygenation (ECMO). Pathology revealed alveolar capillary dysplasia, and ECMO was discontinued. Rapid diagnosis allowed for closure and saved resources. We recommend considering early biopsy in infants with atypical pulmonary hypertension.

Alveolar Capillary Dysplasia with Congenital Misalignment of Pulmonary Vessels

Alveolar capillary dysplasia with misalignment of pulmonary vessels is an uncommon congenital cause of persistent pulmonary hypertension of the newborn. It is universally fatal, and diagnosis is entirely dependent upon surgical lung biopsy. We present a case of alveolar capillary dysplasia with misalignment of pulmonary vessels occurring in a full-term neonate, emphasizing that early involvement of the thoracic surgeon for a histological diagnosis allows expensive and ineffective treatments to be avoided.

Recurrence of alveolar capillary dysplasia with misalignment of pulmonary veins in two consecutive siblings

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare, developmental lung disorder, which has been increasingly reported. This entity usually presents as neonatal persistent pulmonary hypertension that is unresponsive to treatment, and is known to be uniformly fatal. Recent discoveries in the genetic field, and intensive treatments, may change the natural course of this disease, permitting easier diagnosis and giving new hope for the dismal prognosis. The authors present two cases of siblings, with two years of difference, from different fathers - one of them was a first-degree and the other a second-degree cousin of the mother. Both patients were full-term babies born apparently without malformations and were sent to the nursery. Both siblings near 35 hours of age presented severe respiratory failure due to pulmonary hypertension. The outcome was fatal in both cases and at autopsy ACD/MPV was diagnosed. The authors call attention to this entity in the differential diagnosis of acute respiratory distress in early life.

Novel FOXF1 mutations in sporadic and familial cases of alveolar capillary dysplasia with misaligned pulmonary veins imply a role for its DNA binding domain

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare and lethal developmental disorder of the lung defined by a constellation of characteristic histopathological features. Nonpulmonary anomalies involving organs of gastrointestinal, cardiovascular, and genitourinary systems have been identified in approximately 80% of patients with ACD/MPV. We have collected DNA and pathological samples from more than 90 infants with ACD/MPV and their family members. Since the publication of our initial report of four point mutations and 10 deletions, we have identified an additional 38 novel nonsynonymous mutations of FOXF1 (nine nonsense, seven frameshift, one inframe deletion, 20 missense, and one no stop). This report represents an up to date list of all known FOXF1 mutations to the best of our knowledge. Majority of the cases are sporadic. We report four familial cases of which three show maternal inheritance, consistent with paternal imprinting of the gene. Twenty five mutations (60%) are located within the putative DNA-binding domain, indicating its plausible role in FOXF1 function. Five mutations map to the second exon. We identified two additional genic and eight genomic deletions upstream to FOXF1. These results corroborate and extend our previous observations and further establish involvement of FOXF1 in ACD/MPV and lung organogenesis.

16q24.1 microdeletion in a premature newborn: usefulness of array-based comparative genomic hybridization in persistent pulmonary hypertension of the newborn

OBJECTIVE

Report of a 16q24.1 deletion in a premature newborn, demonstrating the usefulness of array-based comparative genomic hybridization in persistent pulmonary hypertension of the newborn and multiple congenital malformations.

DESIGN

Descriptive case report.

SETTING

Genetic department and neonatal intensive care unit of a tertiary care children's hospital.

INTERVENTIONS

None.

PATIENT

We report the case of a preterm male infant, born at 26 wks of gestation. A cardiac malformation and bilateral hydronephrosis were diagnosed at 19 wks of gestation. Karyotype analysis was normal, and a 22q11.2 microdeletion was excluded by fluorescence in situ hybridization analysis. A cesarean section was performed due to fetal distress. The patient developed persistent pulmonary hypertension unresponsive to mechanical ventilation and nitric oxide treatment and expired at 16 hrs of life.

MEASUREMENTS AND MAIN RESULTS

An autopsy revealed partial atrioventricular canal malformation and showed bilateral dilation of the renal pelvocaliceal system with bilateral ureteral stenosis and annular pancreas. Array-based comparative genomic hybridization analysis (Agilent oligoNT 44K, Agilent Technologies, Santa Clara, CA) showed an interstitial microdeletion encompassing the forkhead box gene cluster in 16q24.1. Review of the pulmonary microscopic examination showed the characteristic features of alveolar capillary dysplasia with misalignment of pulmonary veins. Some features were less prominent due to the gestational age.

CONCLUSIONS

Our review of the literature shows that alveolar capillary dysplasia with misalignment of pulmonary veins is rare but probably underreported. Prematurity is not a usual presentation, and histologic features are difficult to interpret. In our case, array-based comparative genomic hybridization revealed a 16q24.1 deletion, leading to the final diagnosis of alveolar capillary dysplasia with misalignment of pulmonary veins. It emphasizes the usefulness of array-based comparative genomic hybridization analysis as a diagnostic tool with implications for both prognosis and management decisions in newborns with refractory persistent pulmonary hypertension and multiple congenital malformations.

Abnormal microRNA expression in Ts65Dn hippocampus and whole blood: contributions to Down syndrome phenotypes

Down syndrome (DS; trisomy 21) is one of the most common genetic causes of intellectual disability, which is attributed to triplication of genes located on chromosome 21. Elevated levels of several microRNAs (miRNAs) located on chromosome 21 have been reported in human DS heart and brain tissues. The Ts65Dn mouse model is the most investigated DS model with a triplicated segment of mouse chromosome 16 harboring genes orthologous to those on human chromosome 21. Using ABI TaqMan miRNA arrays, we found a set of miRNAs that were significantly up- or downregulated in the Ts65Dn hippocampus compared to euploid controls. Furthermore, miR-155 and miR-802 showed significant overexpression in the Ts65Dn hippocampus, thereby confirming results of previous studies. Interestingly, miR-155 and miR-802 were also overexpressed in the Ts65Dn whole blood but not in lung tissue. We also found overexpression of the miR-155 precursors, pri- and pre-miR-155 derived from the miR-155 host gene, known as B cell integration cluster, suggesting enhanced biogenesis of miR-155. Bioinformatic analysis revealed that neurodevelopment, differentiation of neuroglia, apoptosis, cell cycle, and signaling pathways including ERK/MAPK, protein kinase C, phosphatidylinositol 3-kinase, m-TOR and calcium signaling are likely targets of these miRNAs. We selected some of these potential gene targets and found downregulation of mRNA encoding Ship1, Mecp2 and Ezh2 in Ts65Dn hippocampus. Interestingly, the miR-155 target gene Ship1 (inositol phosphatase) was also downregulated in Ts65Dn whole blood but not in lung tissue. Our findings provide insights into miRNA-mediated gene regulation in Ts65Dn mice and their potential contribution to impaired hippocampal synaptic plasticity and neurogenesis, as well as hemopoietic abnormalities observed in DS.

Alveolar capillary dysplasia

Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) is a rare, fatal developmental lung disorder of neonates and infants. This review aims to address recent findings in the etiology and genetics of ACD/MPV and to raise awareness of this poorly known disease, which may also present as milder, unclassified forms. Successively discussed are what is known about the epidemiology, pathogenesis, pathophysiology, diagnostic indicators and approaches, genetic testing, treatment, and cases of delayed onset. The review concludes with suggestions for future directions to answer the many unknowns about this disorder.

Misplaced pulmonary arteries in an adult patient with pulmonary hypertension

Misalignment of pulmonary vessels, with or without alveolar capillary dysplasia, is a rare cause of persistent pulmonary hypertension in the newborn. The prognosis is poor, with virtually all patients succumbing to unremitting hypoxaemic respiratory failure and death during the newborn period. We report the CT and histological findings of misplaced pulmonary arteries in a previously healthy young adult patient who presented with pulmonary arterial hypertension. Contiguous high-resolution spiral CT angiography showed small pulmonary arteries coursing within the interlobular septa and enlarged central pulmonary arteries. Surgical lung biopsy demonstrated anomalous muscularised pulmonary arteries in the interlobular septa. This is, to our knowledge, the first report of misplaced pulmonary arteries presenting in an adult patient and may represent a forme fruste of the neonatal vascular anomaly. A possible association with pulmonary arterial hypertension is also suggested in this case.

Capillary apposition and density in the diagnosis of alveolar capillary dysplasia

AIM

Alveolar capillary dysplasia (ACD) is a rare disorder, typically presenting with persistent pulmonary hypertension of the newborn. The aim was to characterise further the histological features of patients suspected of having ACD and to correlate histopathological features with outcome.

METHODS AND RESULTS

Three pathologists retrospectively reviewed 21 surgical lung biopsy specimens (SLBx) where ACD entered the differential diagnosis. Semi-quantitative assessment showed that there was a spectrum of muscular arterial hypertrophy, capillary apposition to epithelium and capillary density within the interstitium, with the latter being more disordered in ACD. Misalignment of pulmonary vessels was also frequently seen. Four of 19 patients survived beyond the neonatal period, these having higher degrees of capillary apposition and density. Associated extrapulmonary abnormalities were common, most frequently with ACD.

CONCLUSION

Poor capillary apposition and density, allied with medial arterial hypertrophy and misalignment of pulmonary vessels are the strongest diagnostic features of ACD. Of the four patients alive, all had high capillary apposition and density, suggesting that these features may be of prognostic value. SLBx remains useful in such cases as it may help predict patients who survive the neonatal period and also identify patients with disorders that are not primarily vascular anomalies.

Pulmonary arterial hypertension from a pediatric perspective

This review of pediatric pulmonary arterial hypertension provides a framework within which to view pulmonary hypertension in children. Classification schemes, including the latest recommendations from the World Health Organization, are discussed, and the histopathology of severe pulmonary hypertension is reviewed. New information is provided regarding idiopathic and familial forms of the disease. Specific childhood etiologies, including persistent pulmonary hypertension of the newborn and congenital heart disease, are reviewed. Additionally, we examine the role of collagen vascular diseases, portal hypertension, and viruses in the pathogenesis of severe pulmonary arterial hypertension.

A neonate with coexisting congenital cystic adenomatoid malformation of the lung and alveolar capillary dysplasia: a case report with review of literature

OBJECTIVE

First report of a term neonate with coexistent congenital cystic adenomatoid malformation (CCAM) of the lung and alveolar capillary dysplasia (ACD).

METHODS AND DESIGN

Case report and literature review. Our institutional review board waived the need for consent.

SETTING

We describe a term neonate with antenatally diagnosed CCAM and persistent pulmonary hypertension of the newborn (PPHN) who underwent right upper lobe resection on day 9 of life. Histology confirmed CCAM but closer examination also showed ACD. Postoperatively pulmonary hypertension persisted despite high-frequency oscillation and inhaled nitric oxide, and she was placed on extracorporeal membrane oxygenation. Due to the lack of any improvement, intensive care treatment was withdrawn 4 days later.

CONCLUSIONS

This is the first description of an association between these two rare malformations. Although a causative link between CCAM and ACD is possible, it is unlikely. ACD should always be considered as a cause of severe PPHN when persistent beyond 10 days, even if another etiology of PPHN is present.

Atrial septostomy improves survival in select patients with pulmonary hypertension

BACKGROUND

Atrial septostomy is a palliative treatment for patients with pulmonary hypertension (PHTN) refractory to vasodilator therapy. Limited data exist in the pediatric population and in patients with repaired congenital heart defects.

METHODS

We performed a retrospective analysis of hemodynamic and symptomatic changes in patients with PHTN who underwent an atrial septostomy at our institution.

RESULTS

Forty-six atrial septostomies were performed on 43 patients. Patient ages ranged from 0.3 to 30 years (median 12.5). Of 43 patients, 29 had primary PHTN, 10 had PHTN associated with repaired congenital heart defects, and 4 had other secondary causes of PHTN. Mean baseline pulmonary vascular resistance was 35 +/- 17 Wood units, and mean pulmonary artery pressure was 74 +/- 19 mm Hg. Patients surviving > or = 30 days had immediate improvement in cardiac index (from 2.3 to 2.9 L x min(-1) x m(-2), P < .0001), right atrial pressure (RAp) (from 9.9 to 8.3 mm Hg, P < .05), and oxygen delivery (from 424 to 491 mL O2 per minute, P < .01), with a decrease in systemic oxygen saturation (from 93% to 86%, P < .001). Pulmonary artery pressure was unchanged (P = .3). New York Heart Association class and symptoms of syncope improved (P < .01). Event-free survival at 1, 2, and 3 years was 84%, 77%, and 69%, respectively. Using the National Institutes of Health Registry model, predicted survival probability significantly improved (P < .001). Ten patients (22%) died within 30 days of catheterization. Mortality was associated with preceding decompensations in the intensive care unit (6/10, P < .001) and a higher RAp (21.4 vs 9.8 mm Hg, P < .001).

CONCLUSIONS

Atrial septostomy provides symptomatic and hemodynamic improvement in cardiac index and RAp. Risk of septostomy is increased in patients with preceding decompensation or a RAp > 18 mm Hg.

Congenital alveolar capillary dysplasia and associated gastrointestinal anomalies

Congenital alveolar capillary dysplasia is a rare cause of irreversible pulmonary hypertension with 100% mortality. We present three cases of congenital alveolar capillary dysplasia with associated gastrointestinal abnormalities. Three full-term neonates presented with pulmonary hypertension needing ventilatory support by oscillation. Of the three, two neonates subsequently needed extracorporeal membrane oxygenation. Abdominal distension associated with bilious aspirates was the gastrointestinal manifestation. One child had duodenal atresia and anorectal anomaly, one with intestinal malrotation and the other with a rare combination of intestinal malrotaion and total colonic Hirschsprung's disease. All three infants succumbed to pulmonary hypertension at mean age 34 days. The etiopathogenesis and pathology of this condition are discussed with a comprehensive review of the literature.

Late presentation of alveolar capillary dysplasia in an infant

OBJECTIVE

To report a case of late presentation of alveolar capillary dysplasia and misalignment of pulmonary veins.

DESIGN

Descriptive case report.

SETTING

Pediatric intensive care unit of a tertiary care children's hospital.

PATIENT

Seven-week-old female infant with severe hypoxemic respiratory failure.

CONCLUSION

Alveolar capillary dysplasia with misalignment of pulmonary veins is a cause of primary pulmonary hypertension in newborns that can rarely present past the newborn period. Early lung biopsy can be helpful in establishing the diagnosis and avoiding ineffective, futile, and expensive therapeutic interventions.

Misalignment of pulmonary vessels with alveolar capillary dysplasia: association with atrioventricular septal defect and quadricuspid pulmonary valve

Misalignment of pulmonary vessels (MPV) with alveolar capillary dysplasia (ACD) is a complex congenital vascular abnormality in newborn infants. This condition is often associated with persistent pulmonary hypertension, which leads to severe respiratory distress and finally to the death of the newborn. Here, two cases of MPV with ACD are reported that were associated with atrioventricular septal defects. Both cases showed a combination of a large atrial septal defect and a smaller subvalvular ventricular septal defect. In one newborn, the cardiac malformation was accompanied by a quadricuspid pulmonary valve. These cases emphasize the importance of considering MPV with ACD a possible cause for pulmonary hypertension in the newborn, especially when a concomitant atrioventricular septal defect could represent an alternative explanation for the pulmonary hypertension.

Alveolar capillary dysplasia: a six-year single center experience

Alveolar capillary dysplasia is a fatal disorder of the lung that requires lung biopsy for diagnosis. We reviewed the course of patients with alveolar capillary dysplasia following implementation of an early lung biopsy strategy between 1997-2002. We performed immunohisto-chemical studies on all tissue specimens. We diagnosed 7 cases of alveolar capillary dysplasia. We diagnosed 6/7 cases of alveolar capillary dysplasia pre-mortem by early lung biopsy. Median time between admission and lung biopsy was 6.5 days. All patients survived lung biopsy but died following withdrawal of active therapy after confirmation of the tissue diagnosis. In 1 patient we demonstrated histological findings of alveolar capillary dysplasia and congenital acinar dysplasia. Two patients were first cousins. One patient underwent pulmonary angiography with rapid filling of the pulmonary veins before passage of contrast through the capillary bed. Five patients were supported with extracorporeal membrane oxygenation and 2/5 patients survived decannulation. During the same period 8 patients required ECMO for acute hypoxic respiratory failure. Four out of 8 were diagnosed with alveolar capillary dysplasia.

CONCLUSIONS

Early lung biopsy was performed with low risk and high diagnostic yield for alveolar capillary dysplasia. Alveolar capillary dysplasia occurs frequently in neonates who require ECMO support for refractory pulmonary hypertension. We have added an additional familial case and suggest a novel angiographic finding.

Alveolar capillary dysplasia in an infant with trisomy 21

We present a case of an infant with Down syndrome (trisomy 21) who was affected by alveolar capillary dysplasia and other complications including endocardial cushion defect, hypothyroidism, and intrauterine growth restriction. The patient was the product of a third pregnancy to a 33-year-old woman with no significant risk factors. The child lived for 3 months, during which he developed intractable dyspnea, hypoxemia, and cardiac dysfunction and he eventually died from septicemia and multiorgan failure. In addition to the facial phenotypic features and cardiac anomalies, the autopsy revealed the characteristic microscopic pulmonary findings of alveolar capillary dysplasia with misalignment of pulmonary veins. This appears to be the first reported case of this anomaly associated with trisomy 21. In addition to the many reasons for pulmonary hypertension that occur in children with trisomy 21, alveolar capillary dysplasia may have to be included in the differential diagnosis although it appears to be a rare association.

Alveolar capillary dysplasia: a logical approach to a fatal disease

PURPOSE

The aim of the study was to review the authors' experience with alveolar capillary dysplasia (ACD), a cause of persistent pulmonary hypertension of the neonate (PPHN) caused by decreased alveolar units, dilated anomalous pulmonary veins, thick-walled arterioles, and thickened interalveolar septa.

METHODS

The records of all neonates with ACD were reviewed from Children's Hospital, Columbus, Ohio, and Sophia's Children's Hospital, Rotterdam, The Netherlands. The clinical characteristics and pathological findings are discussed.

RESULTS

Eight neonates were diagnosed with ACD from 1994 to 2002. Twenty-five percent (2/8) experienced respiratory distress immediately after birth, whereas 75% (6/8) had normal Apgar scores but deteriorated 1.5 hours to 30 days after birth. All infants required conventional ventilation initially; 50% (4/8) were placed on high-frequency oscillating ventilation and 87% (7/8) on extracorporeal membrane oxygenation. A premorbid diagnosis was established in 3 patients by open lung biopsy. The diagnosis of ACD was confirmed at autopsy in all patients.

CONCLUSIONS

ACD is a fatal disease that should be suspected in all neonates with respiratory failure and PPHN who fail conventional therapy. Prompt diagnosis helps to avoid prolongation of costly treatment modalities in a uniformly fatal disease. An algorithm is proposed in which neonates with PPHN who fail treatment with extracorporeal membrane oxygenation are managed by open lung biopsy.

Rescue of monocrotaline-induced pulmonary arterial hypertension using bone marrow-derived endothelial-like progenitor cells: efficacy of combined cell and eNOS gene therapy in established disease

Pulmonary arterial hypertension (PAH) is characterized by a progressive increase in pulmonary vascular resistance caused by narrowing and loss of pulmonary microvasculature, which in its late stages becomes refractory to traditional therapies. We hypothesized that bone marrow-derived endothelial progenitor cells (EPCs), which normally function to repair and regenerate blood vessels, would restore pulmonary hemodynamics and increase microvascular perfusion in the rat monocrotaline (MCT) model of PAH. Mononuclear cells were isolated from the bone marrow of syngeneic Fisher-344 rats by Ficoll gradient centrifugation and cultured for 7 to 10 days in endothelial growth medium. Fluorescently labeled endothelial-like progenitor cells (ELPCs) engrafted at the level of the distal pulmonary arterioles and incorporated into the endothelial lining in the MCT-injured lung. The administration of ELPCs 3 days after MCT nearly completely prevented the increase in right ventricular systolic pressure seen at 3 weeks with MCT alone (31.5+/-0.95 versus 48+/-3 mm Hg, respectively; P<0.001), whereas injection of skin fibroblasts had no protective effect (50.9+/-5.4 mm Hg). Delayed administration of progenitor cells 3 weeks after MCT prevented the further progression of PAH 2 weeks later (ie, 5 weeks after MCT), whereas only animals receiving ELPCs transduced with human endothelial NO-synthase (eNOS) exhibited significant reversal of established disease at day 35 (31+/-2 mm Hg, P<0.005) compared with day 21 (50+/-3 mm Hg). Fluorescent microangiography revealed widespread occlusion of pulmonary precapillary arterioles 3 weeks after MCT, whereas arteriolar-capillary continuity and microvascular architecture was preserved with the administration of syngeneic ELPCs. Moreover, the delivery of ELPCs to rats with established PAH resulted in marked improvement in survival, which was greatest in the group receiving eNOS-transduced cells. We conclude that bone marrow-derived ELPCs can engraft and repair the MCT-damaged lung, restoring microvasculature structure and function. Therefore, the regeneration of lung vascular endothelium by injection of progenitor cells may represent a novel treatment paradigm for patients with PAH.

Pulmonary pathology

Common causes of neonatal respiratory distress include meconium aspiration, pneumonia, persistent pulmonary hypertension of the newborn, pneumothorax and cystic adenomatoid malformation. Genomics and proteomics have enabled the recent recognition of several additional disorders that lead to neonatal death from respiratory disease. These are broadly classified as disorders of lung homeostasis and have pathological features of proteinosis, interstitial pneumonitis or lipidosis. These pathological changes result from inherited disorders of surfactant proteins or granulocyte-macrophage colony stimulating factor. Abnormal lung vascular development is the basis for another cause of fatal neonatal respiratory distress, alveolar capillary dysplasia with or without associated misalignment of veins. Diagnosis of these genetically transmitted disorders is important because of the serious implications for future siblings. There is also a critical need for establishing an archival tissue bank to permit future molecular biological studies.

Dysplasie alvéolo-capillaire avec défaut d’alignement des vaisseaux pulmonaires

Alveolar capillary dysplasia (ACD), with or without pulmonary vein misalignment is a uniformly fatal cause of persistent pulmonary hypertension and respiratory failure, first described in 1981. We report the case of ACD in a full term newborn with post mortem pathologic confirmation. Sixty five cases have been reported in the literature, most are sporadic, but a few cases of familial ACD suggest an autosomal recessive inheritance. In 55% of the reported cases of ACD other cardiovascular, digestive or urogenital anomalies were associated. ACD is presumed to be a primary capillary disorder. It affects full-term neonates who exhibit respiratory distress during the early post natal period due to pulmonary hypertension and die within 3 weeks of birth. Histologic findings include a decrease in the number of alveolar capillaries, which are placed centrally within the intralobular septa, ectatic veins accompany the bronchovascular bundles instead of being in their normal position in the interlobular septum, and muscularized pulmonary arteries extend to the distal level. Prognosis is very poor, intravenous prostacyclin with inhaled nitric oxide have been reported in the cases with the best survival.