Alice Hadchouel

Identification of SPOCK2 as a susceptibility gene for bronchopulmonary dysplasia

RATIONALE Bronchopulmonary dysplasia is the most common chronic respiratory disease in premature infants. Genetic factors might contribute to bronchopulmonary dysplasia susceptibility. OBJECTIVES To identify genetic variants involved in bronchopulmonary dysplasia through a genome-wide association study. METHODS We prospectively evaluated 418 premature neonates (gestational age <28 wk), of whom 22% developed bronchopulmonary dysplasia. Two discovery series were created, using a DNA pooling strategy in neonates from white and African ancestry. Polymorphisms associated with the disease were confirmed in an independent replication population. Genes were then explored by fine mapping and associations were replicated in an external Finnish population of 213 neonates. Validated genes expression patterns were studied in rat lung, after air or hyperoxia exposure. MEASUREMENTS AND MAIN RESULTS SPOCK2 gene was identified by both discovery series. The most significant polymorphism (rs1245560; P = 1.66 × 10(-7)) was confirmed by individual genotyping, and in the replication population (P = 0.002). Fine mapping confirmed the association of rs1245560 with bronchopulmonary dysplasia in both white and African populations with adjusted odds ratios of 2.96 (95% confidence interval [CI], 1.37-6.40) and 4.87 (95% CI, 1.88-12.63), respectively. In white neonates, rs1049269 was also associated with the disease (odds ratio, 3.21; 95% CI, 1.51-6.82). These associations were replicated in the Finnish population. In newborn rat lungs, SPOCK2 mRNA levels markedly increased during the alveolar stage of lung development. After rat exposure to hyperoxia, SPOCK2 expression increased relative to air-exposed controls. CONCLUSIONS We identified SPOCK2 as a new possible candidate susceptibility gene for bronchopulmonary dysplasia. Its lung expression pattern points toward a potential role in alveolarization.

Biallelic Mutations of Methionyl-tRNA Synthetase Cause a Specific Type of Pulmonary Alveolar Proteinosis Prevalent on Réunion Island

Methionyl-tRNA synthetase (MARS) catalyzes the ligation of methionine to tRNA and is critical for protein biosynthesis. We identified biallelic missense mutations in MARS in a specific form of pediatric pulmonary alveolar proteinosis (PAP), a severe lung disorder that is prevalent on the island of Réunion and the molecular basis of which is unresolved. Mutations were found in 26 individuals from Réunion and nearby islands and in two families from other countries. Functional consequences of the mutated alleles were assessed by growth of wild-type and mutant strains and methionine-incorporation assays in yeast. Enzyme activity was attenuated in a liquid medium without methionine but could be restored by methionine supplementation. In summary, identification of a founder mutation in MARS led to the molecular definition of a specific type of PAP and will enable carrier screening in the affected community and possibly open new treatment opportunities.

Neonatal Outcomes of Prenatally Diagnosed Congenital Pulmonary Malformations

BACKGROUND AND OBJECTIVE: Congenital pulmonary malformations (CPM) are mostly recognized on prenatal ultrasound scans. In a minority of cases, they may impair breathing at birth. The factors predictive of neonatal respiratory distress are not well defined, but an understanding of these factors is essential for decisions concerning the need for the delivery to take place in a tertiary care center. The aim of this study was to identify potential predictors of respiratory distress in neonates with CPM. METHODS: We selected cases of prenatal diagnosis of hyperechoic and/or cystic lung lesions from RespiRare, the French prospective multicenter registry for liveborn children with rare respiratory diseases (2008–2013). Prenatal parameters were correlated with neonatal respiratory outcome. RESULTS: Data were analyzed for 89 children, 22 (25%) of whom had abnormal breathing at birth. Severe respiratory distress, requiring oxygen supplementation or ventilatory support, was observed in 12 neonates (13%). Respiratory distress at birth was significantly associated with the following prenatal parameters: mediastinal shift (P = .0003), polyhydramnios (P = .05), ascites (P = .0005), maximum prenatal malformation area (P = .001), and maximum congenital pulmonary malformation volume ratio (CVR) (P = .001). Severe respiratory distress, requiring oxygen at birth, was best predicted by polyhydramnios, ascites, or a CVR >0.84. CONCLUSIONS: CVR >0.84, polyhydramnios, and ascites increased the risk of respiratory complications at birth in fetuses with CPM, and especially of severe respiratory distress, requiring oxygen supplementation or more intensive intervention. In such situations, the delivery should take place in a tertiary care center.

Shall all congenital cystic lung malformations be removed? the case in favour.

The need to systematically remove congenital cystic lung lesions is based on three main arguments. First, cystic malformations are often considered as congenital cystic adenomatoid malformations (CCAM), while other less favorable diagnoses are possible, such as pleuropulmonary blastoma. Only postsurgical pathological analysis allows diagnosis. Second, there are clinical and biological arguments for considering macrocystic lesions as likely to degenerate. The only prevention is surgical removal. Finally, there is no recommendation on how to follow these children, in the absence of removal, causing unnecessary family stress. This seems unjustified, compared to a feasibility of thoracoscopic removal in most cases.

Long term respiratory outcomes of congenital diaphragmatic hernia, esophageal atresia, and cardiovascular anomalies

Intrathoracic congenital malformations may be associated with long-term pulmonary morbidity. This certainly is the case for congenital diaphragmatic hernia, esophageal atresia and cardiac and aortic arch abnormalities. These conditions have variable degrees of impaired development of both the airways and lung vasculature, with a postnatal impact on lung function and bronchial reactivity. Pulmonary complications are themselves frequently associated to non-pulmonary morbidities, including gastrointestinal and orthopaedic complications. These are best recognized in a structured multidisciplinary follow-up clinic so that they can be actively managed.

Pulmonary alveolar proteinosis in children on La Réunion Island: a new inherited disorder?

BackgroundPulmonary alveolar proteinosis (PAP) is very rare in children. Only a few small series have been published, with little information about long-term progression. The objective of our study was to describe the clinical, radiological and pathological features, and the long-term course of PAP in a cohort of 34 children from La Réunion Island.MethodsData were retrospectively collected from medical files. Radiological and pathological elements were reviewed by two pediatric radiologists and three pathologists, respectively.ResultsThirteen cases were familial and 32/34 (94%) cases were family connected. Disease onset occurred in the first six months of life in 82% of the patients. Thoracic computed tomography scans showed the typical “crazy-paving” pattern in 94% of cases. Respiratory disease was associated with a liver disorder, with the detection of liver enlargement at diagnosis in 56% of cases. The course of the disease was characterized by frequent progression to chronic respiratory insufficiency, accompanied by the appearance of cholesterol granulomas and pulmonary fibrosis. Overall prognosis was poor, with a mortality of 59% and an overall five-year survival rate from birth of 64%. Whole-lung lavages were performed in 21 patients, with no significant effect on survival. Liver disease progressed to cirrhosis in 18% of children, with no severe complication.ConclusionsPAP in children from la Réunion Island is characterized by an early onset, associated liver involvement, poor prognosis and frequent progression to lung fibrosis, despite whole-lung lavages treatment. The geographic clustering of patients and the detection of many familial links between most of the cases strongly suggest a genetic etiology, with an autosomal recessive mode of inheritance.

Eosinophilic pneumonias in children: A review of the epidemiology, diagnosis, and treatment.

Pediatric eosinophilic pneumonias (EPs) are characterized by a significant infiltration of the alveolar spaces and lung interstitium by eosinophils, with conservation of the lung structure. In developed countries, EPs constitute exceptional entities in pediatric care. Clinical symptoms may be transient (Löffler syndrome), acute (<1 month and mostly <7 days), or chronic (>1 month). Diagnosis relies on demonstration of alveolar eosinophilia on bronchoalveolar lavage, whether or not associated with blood eosinophilia. EPs are a heterogeneous group of disorders divided into: (i) secondary forms (seen mainly in parasitic infections, allergic bronchopulmonary aspergillosis, and drug reactions); and (ii) primary forms (eosinophilic granulomatosis with polyangiitis, hypereosinophilic syndrome, idiopathic chronic eosinophilic pneumonia, and idiopathic acute eosinophilic pneumonia). Despite their rarity, the etiological approach to EP must be well‐defined as some causes can be rapidly life‐threatening without initiation of the proper treatment. This approach (i) eliminates secondary forms, with comprehensive history taking and minimal biological assessment, (ii) is oriented in primary forms by the acute or chronic setting, and the existence of extrapulmonary symptoms. Treatment of primary forms has traditionally relied on corticosteroids, usually with a dramatic response. Specific treatments or the adjunction of corticosteroid‐sparing treatment or immunosuppressors are currently being evaluated in order to improve the prognosis and the side effects associated with corticosteroid treatment in a pediatric setting. Pediatr Pulmonol. 2016;51:203–216.

Idiopathic eosinophilic pneumonia in children: the French experience

BackgroundIdiopathic eosinophilic pneumonia is extremely rare in children and adults. We present herein the first series describing the specificities of idiopathic chronic (ICEP) and acute (IAEP) eosinophilic pneumonia in children.MethodsWe retrospectively analyzed all cases of ICEP and IAEP in children that were retrieved from French Reference Centers for rare pediatric lung diseases.ResultsFive cases of pediatric ICEP were identified. Corticosteroid or immunosuppressive therapy dramatically improved the outcome in three cases. The remaining two cases had a persistent interstitial pattern with progressive development of cystic airspace lesions. Three cases of IAEP in adolescents were reported, with one requiring four days of extracorporeal membrane oxygenation.ConclusionICEP is a rare disease with a polymorphic clinical presentation in children. We identified patients with persistent interstitial patterns progressing to cystic airspace regions, for which the boundaries with idiopathic interstitial pneumonias are difficult to establish. We therefore propose a specific pediatric definition and classification algorithm. IAEP in children remains an inflammatory reaction of the lung to an acute toxic exposure, mainly tobacco, as in adults. International studies are required to comprehensively assess the various clinical forms of the disease as well as the appropriate therapeutic regimens.

Pathomechanisms of Congenital Cystic Lung Diseases: Focus on Congenital Cystic Adenomatoid Malformation and Pleuropulmonary Blastoma

It is well established that a number of birth defects are associated with improper formation of the respiratory tract. Important progress has been made in the identification of components of the regulatory networks controlling lung morphogenesis. They comprise a variety of soluble factors, receptors, transcription factors, and miRNAs. However, the underlying molecular mechanisms remain unsolved and fundamental questions, such as those related to lung branching are still unanswered. Congenital cystic lung diseases consist of a heterogeneous group of rare lung diseases mainly detected prenatally and characterized by airway dilatation. Despite their apparent phenotypic heterogeneity, these malformations are proposed to be related to a common malformation sequence occurring during lung branching morphogenesis.

Respiratory Morbidity in Infants Born With a Congenital Lung Malformation

In a multicenter cohort of children with congenital lung malformation, this study evaluates the frequency of respiratory symptoms and factors associated to their occurrence. BACKGROUND AND OBJECTIVES: The actual frequency of respiratory symptoms related to congenital pulmonary malformations (CPMs) remains undetermined. The goal of this study was to prospectively evaluate the respiratory symptoms occurring in infants with prenatally diagnosed CPMs, identify factors associated with the occurrence of these symptoms, and evaluate their resolution after surgery. METHODS: Infectious and noninfectious respiratory symptoms were prospectively collected in a French multicenter cohort of children with CPMs. RESULTS: Eighty-five children were followed up to the mean age of 2.1 ± 0.4 years. Six children (7%) underwent surgery during the first 28 days of life. Of the 79 remaining children, 33 (42%) had respiratory symptoms during infancy before any surgery. Wheezing was the dominant symptom (24 of 79 [30%]), and only 1 infant had documented infection of the cystic lobe. Symptoms were more frequent in children with noncystic CPMs, prenatally (P = .01) or postnatally (P < .03), and with postnatally hyperlucent CPMs (P < .01). Sixty-six children underwent surgery during the follow-up period, and 40% of them displayed symptoms after the intervention. Six children had documented pneumonia during the postoperative period. At the end of the follow-up, pectus excavatum was observed in 10 children, significantly associated with thoracotomy (P < .02) or with surgery before the age of 6 months (P < .002). CONCLUSIONS: CPMs are frequently associated with wheezing episodes. Surgery had no significant impact on these symptoms but was associated with a paradoxical increase in pulmonary infections, as well as an increased risk of pectus excavatum after thoracotomy.