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Background: Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a lethal congenital lung disorder associated with heterozygous variants in the FOXF1 gene or its regulatory region. Patients with ACD/MPV unnecessarily undergo invasive and expensive treatments while awaiting a diagnosis. The aim of this study was to reduce the time to diagnose ACD/MPV by developing a targeted next-generation sequencing (NGS) panel that detects FOXF1 variants. Methods: A FOXF1-targeted NGS panel was developed for detection of mutations and large genomic alterations and used for retrospective testing of ACD/MPV patients and controls. Results were confirmed with Sanger sequencing and SNP array analysis. Results: Each amplicon of the FOXF1-targeted NGS panel was efficiently sequenced using DNA isolated from blood or cell lines of 15 ACD/MPV patients and 8 controls. Moreover, testing of ACD/MPV patients revealed six novel and six previously described pathogenic or likely pathogenic FOXF1 alterations. Conclusion: We successfully designed a fast and reliable targeted genetic test to detect variants in the FOXF1 gene and its regulatory region in one run. This relatively noninvasive test potentially prevents unnecessary suffering for patients and reduces the use of futile and expensive treatments like extra-corporeal membrane oxygenation. Impact: FOXF1-targeted NGS potentially prevents ACD/MPV patients from unnecessary suffering and expensive treatments.FOXF1-targeted NGS potentially reduces the number of misdiagnosis in ACD/MPV patients.Retrospective testing of ACD/MPV patients using FOXF1-targeted NGS revealed six novel pathogenic or likely pathogenic variants.

BACKGROUND: Alveolar capillary dysplasia (ACD) is a rare cause of severe pulmonary hypertension and respiratory failure in neonates. The onset of ACD is usually preceded by a short asymptomatic period. The condition is refractory to all available therapies as it irreversibly affects development of the capillary bed in the lungs. The diagnosis of ACD is based on histopathological evaluation of lung biopsy or autopsy tissue or genetic testing of FOXF1 on chromosome 16q24.1. Here, we describe the first two Polish patients with ACD confirmed by histopathological and genetic examination. CASE PRESENTATION: The patients were term neonates with high Apgar scores in the first minutes of life. They both were diagnosed prenatally with heart defects. Additionally, the first patient presented with omphalocele. The neonate slightly deteriorated around 12th hour of life, but underwent surgical repair of omphalocele followed by mechanical ventilation. Due to further deterioration, therapy included inhaled nitric oxide (iNO), inotropes and surfactant administration. The second patient was treated with prostaglandin E1 since birth due to suspicion of aortic coarctation (CoA). After ruling out CoA in the 3rd day of life, infusion of prostaglandin E1 was discountinued and immediately patient's condition worsened. Subsequent treatment included re-administration of prostaglandin E1, iNO and mechanical ventilation. Both patients presented with transient improvement after application of iNO, but died despite maximized therapy. They were histopathologically diagnosed post-mortem with ACD. Array comparative genomic hybridization in patient one and patient two revealed copy-number variant (CNV) deletions, respectively, ~ 1.45 Mb in size involving FOXF1 and an ~ 0.7 Mb in size involving FOXF1 enhancer and leaving FOXF1 intact. CONCLUSIONS: Both patients presented with a distinct course of ACD, extra-pulmonary manifestations and response to medications. Surgery and ceasing of prostaglandin E1 infusion should be considered as potential causes of this variability. We further highlight the necessity of thorough genetic testing and histopathological examination and propose immunostaining for CD31 and CD34 to facilitate the diagnostic process for better management of infants with ACD.

Background Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare disorder of pulmonary vascular abnormality with persistent pulmonary hypertension of the newborn. The symptom usually presents within hours after birth, leading to an early demise. Heterozygous de novo point mutations and genomic deletions of the FOXF1 (forkhead box F1) gene or its upstream enhancer have been identified in most patients with ACD/MPV. Most cases of ACD/MPV are sporadic; however, familial cases are also reported in 10% of patients. Case presentation We herein report a case of familial ACD/MPV that showed unusual glomeruloid proliferation of endothelial cells. In this family, three of the four siblings died within two to 3 days after birth because of persistent pulmonary hypertension and respiratory failure. Only the second child remains alive and healthy. An autopsy was performed for the third and fourth children, resulting in a diagnosis of ACD/MPV based on the characteristic features, including misalignment of smaller pulmonary veins and lymphangiectasis. In both of these children, glomeruloid endothelial proliferation of vessels was noted in the interlobular septa. The vessels were immunohistochemically positive for D2–40, CD31, Factor VIII, and ERG, suggestive of differentiation for both lymphatic and blood vessels. Conclusions Unusual glomeruloid endothelial proliferation was observed in a familial ACD/MPV case. This histologic feature has not been described previously in ACD/MPV or any other pulmonary disease. Although the histogenesis of this histologic feature is unclear, this finding may suggest that ACD/MPV is a compound vascular and lymphovascular system disorder that exhibits various histologic features.

This report demonstrates a late presenter and long-term survivor (38 months old) of alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) and with a heterozygous frameshift mutation in FOXF1. The mild phenotype may be due to his residual normal lung tissue as demonstrated in the chest computed tomography (CT) and histopathological findings.We report the longest survivor of ACD/MPV. The mild phenotype is most likely due to the patient's residual normal lung tissue.

BACKGROUND: Genetic variations associated with interstitial lung diseases (ILD) have not been extensively studied in Japanese infants. METHODS: Forty-three infants with unexplained lung dysfunction were studied. All 43, 22, and 17 infants underwent analyses of surfactant protein (SP)-C gene (SFTPC) and ATP-binding cassette A3 gene (ABCA3), SP-B gene (SFTPB), and SP-B western blotting, respectively. Two and four underwent assessment of granulocyte macrophage colony-stimulating factor-stimulating phosphorylation of signal transducer and activator of transcription-5 (pSTAT-5) and analyses of FOXF1 gene (FOXF1), respectively. RESULTS: ILD were diagnosed clinically in nine infants: four, three, and two had interstitial pneumonitis, hereditary pulmonary alveolar proteinosis (hPAP), and alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV), respectively. Genetic variations considered responsible were detected in six (67%) of the nine infants with ILD: three with hPAP (SFTPC p.Leu45Arg and p.Gln145fs, and ABCA3 p.Arg1583Trp/p.Val1495CysfsX21), two with interstitial pneumonitis (SFTPC p.Lys63Glu and p.Ser72Asn/p.Gly100Ala), and one with ACD/MPV (FOXF1 p.Leu300ArgfsX79). None showed SFTPB mutations or defects in pSTAT-5. The 17 bron-choalveolar lavage or tracheal aspirates contained enough SP-B protein. CONCLUSION: The SP-C abnormality was most prevalent, and SP-B deficiency was rare in Japanese infants with hereditary-ILD.

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare, fatal, congenital lung disorder involving abnormal development of the capillary vascular system around the alveoli of the lungs, which clinically presents as persistent pulmonary hypertension of the newborn (PPHN) refractory to treatment. It has been linked to the gene FOXF1 on chromosome 16q24.1–q24.2. Histopathological examination by lung biopsy is the gold standard for diagnosis. We present four cases of ACD/MPV who were referred for ECMO support with a diagnosis of PPHN with no apparent congenital anomalies. All the newborns had an overwhelming course, with PPHN and hypoxemia refractory to treatment. The diagnosis of ACD/MPV was established by ante-mortem lung biopsy in all cases. Intensive care treatment was withdrawn post diagnosis, with none of the four surviving. Early lung biopsy for a histological diagnosis allows expensive and ineffective treatment to be avoided. Lung biopsy can be performed with low risk and high-diagnostic yield for alveolar capillary dysplasia.

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.

Background: Full-term infants with severe and prolonged respiratory distress represent a diagnostic challenge. Plain radiographic findings may be nonspecific or similar to classic surfactant deficiency disease for infants with surfactant protein B deficiency and acinar dysplasia. Objectives: To describe the similar clinical-radiolgical patterns of two rare neonatal conditions. Materials and methods: Six newborn babies with severe respiratory distress at birth demonstrated clinical and radiographically prolonged and progressive diffuse pulmonary opacification. Results: All infants demonstrated hyperinflation of the lungs. The diffuse hazy opacification, which varied from mild (n=3) to moderate (n=3), progressed to severe diffuse opacification preceding death, which occurred at 12–36 days of life. Open lung biopsy confirmed the diagnosis of primary alveolar acinar dysplasia (AD) in four infants and surfactant protein B deficiency (SPBD) in two infants. Conclusions: In full-term babies with unexplained progressive respiratory distress from birth and progress of radiological changes, both AD and SPBD should be considered.

The term alveolar capillary dysplasia refers to complex vascular abnormalities which have recently been identified in some infants with persistent pulmonary hypertension. We report four cases admitted to our institution for severe pulmonary hypertension unresponsive to maximal cardiorespiratory support, including high-frequency ventilation, inhaled nitric oxide and extracorporeal membrane oxygenation. The four infants died of refractory hypoxaemia. The diagnosis of alveolar capillary dysplasia was established by necropsy. We have used these cases as an opportunity for a thorough review of the literature containing comments regarding aetiology, pathophysiology, clinical presentation, associated malformations and treatment trials. Conclusion: alveolar capillary dysplasia should be ruled out in all newborn infants presenting severe idiopathic pulmonary hypertension associated with malformations. Open lung biopsy may prevent from using costly, invasive and probably ineffective procedures such as extracorporeal membrane oxygenation.

The association of alveolar capillary dysplasia with misalignment of pulmonary veins (ACD-MPV) and ocular abnormalities has not been previously reported. We present a case of ACD-MPV and anterior segment dysgenesis of the eye in a full-term infant as well as a review of the relevant literature.

Alveolar capillary dysplasia (ACD), which is a rare and lethal congenital pulmonary anomaly found in newborns, begins its onset or causes deterioration of the infant's condition some time after birth. Various congenital anomalies in combination with ACD have been reported, except for subglottic stenosis. Therefore, we aim to report a novel association in a case of ACD with the combination of atypical duodenal atresia and subglottic stenosis. The male infant was scheduled for duodeno-duodenostomy because a double-bubble sign was observed on a chest radiograph. He arrived at the operating theater without any symptoms. After induction of general anesthesia, although mask ventilation was performed without difficulties throughout the entire procedure, oxygen saturation values of the upper and lower extremities dissociated after several attempts of intubation. Surgery was canceled because of instability of the respiratory condition. Respiratory insufficiency worsened progressively, and the infant died at 5 days of age. An autopsy confirmed ACD and revealed cartilaginous subglottic stenosis, which had made intubation difficult. This report highlights the hazards of the onset and worsening of ACD, and the importance of thorough echocardiography before surgery when atypical duodenal atresia is suspected. Anesthesiologists should also be prepared for the difficulty of intubation.

Congenital misalignment of pulmonary vessels (MPV) with alveolar capillary dysplasia is a rare condition consisting of anomalous veins in bronchovascular bundles, a decreased number of alveolar capillaries, and increased muscularization of pulmonary arterioles. In the literature, infants reported as having such a malformation developed respiratory distress with persistent pulmonary hypertension and ultimately died. We report the case of an infant with MPV and alveolar capillary dysplasia who was unresponsive to maximal cardiorespiratory support, including high-frequency oscillatory ventilation and inhaled nitric oxide; the infant died of pulmonary hemorrhage after 19 days, during venoarterial extracorporeal membrane oxygenation bypass. We conclude that the diagnosis of MPV and alveolar capillary dysplasia should be considered during autopsy of infants who have died of irreversible persistent pulmonary hypertension. If a lung biopsy in infants with prolonged refractory hypoxemia confirms such diagnosis before death, expensive and invasive treatments such as extracorporeal membrane oxygenation could be avoided.

We describe two neonates with a lethal form of pulmonary maldevelopment. Both infants had bilateral dysplastic immature lungs with poor capillary formation and lack of alveolar development. This rare entity should be considered in the differential diagnosis of a newborn infant with mild diffuse radiographic pulmonary abnormality and severe respiratory distress.

The Potential Role for Cardiac Catheterization in the Pre-Mortem Diagnosis of Alveolar Capillary Dysplasia 1668

Alveolar capillary dysplasia (ACD) has assumed clinical importance because of the associated pulmonary hypertension that fails to respond to ECMO. We present two term infants with ACD and congenital heart disease who both failed ECMO therapy. The lungs were filled and fixed postmortem with 10% formalin at 24 cm H2O pressure. Tissue blocks from the left lung were later fixed with glutaraldehyde, cut 1 mm thick and stained with toluidine blue to assess alveolar capillary density. Regular 5-μm sections were stained with hematoxylin and eosin for lung histology. The two infants had pulmonary lobules with round, immature air spaces, lined by cuboidal epithelium separated by hypocapillarized thickened walls (ACD). One infant also had small malpositioned veins accompanying small pulmonary arteries (misalignment of the pulmonary veins; MPV), cortriatrium, and a hypoplastic left heart. The other had no MPV, pulmonary lymphangiectasia, right lung isomerism, and double outlet right ventricle. In conclusion, ACD may occur with and without MPV, possibly depending upon the stage of development during which the abnormality occurs. Eighty-five percent of infants with ACD have additional congenital abnormalities. ACD with and without MPV should be suspected in those newborns with persistent pulmonary hypertension, especially when congenital abnormalities are present.