Interstitial lung disease in newborns

Epidemiology of childhood interstitial lung disease in France: the RespiRare cohort

INTRODUCTION

Interstitial lung disease in children (chILD) are rare and mostly severe lung diseases. Very few epidemiological data are available in limited series of patients. The aim of this study was to assess the prevalence and incidence of chILD in France.

METHODS

We performed within the RespiRare network a multicentre retrospective observational study in patients with chILD from 2000 to 2022 and a prospective evaluation of chILD's incidence between February 2022 and 2023.

RESULTS

chILD was reported in 790 patients in 42 centres. The estimated 2022 prevalence in France was 44 /million children (95% CI 40.76 to 47.46) and the computed incidence was 4.4 /million children (95% CI 3.44 to 5.56). The median age at diagnosis was 3 months with 16.9% of familial forms. Lung biopsy and genetic analyses were performed in 23.4% and 76.9%, respectively. The most frequent chILD aetiologies in the <2 years group were surfactant metabolism disorders (16.3%) and neuroendocrine cell hyperplasia of infancy (11.8%), and in the 2-18 years group diffuse alveolar haemorrhage (12.2%), connective tissue diseases (11.4%), hypersensitivity pneumonitis (8.8%) and sarcoidosis (8.8%). The management included mainly oxygen therapy (52%), corticosteroid pulses (56%), oral corticosteroids (44%), azithromycin (27.2%), enteral nutrition (26.9%), immunosuppressants (20.3%) and hydroxychloroquine (15.9%). The 5-year survival rate was 57.3% for the patients diagnosed before 2 years and 86% between 2 and 18 years.

CONCLUSION

This large and systematic epidemiological study confirms a higher incidence and prevalence of chILD than previously described. In order to develop international studies, efforts are still needed to optimise the case collection and to harmonise diagnostic and management practices.

Interstitial lung disease in the newborn

Although relatively rare, interstitial lung diseases may present with respiratory distress in the newborn period. Most commonly these include developmental and growth disorders, disorders of surfactant synthesis and homeostasis, pulmonary interstitial glycogenosis, and neuroendocrine cell hyperplasia of infancy. Although the diagnosis of these disorders is sometimes made based on clinical presentation and imaging, due to the significant overlap between disorders and phenotypic variability, lung biopsy or, increasingly genetic testing is needed for diagnosis. These diseases may result in significant morbidity and mortality. Effective medical treatment options are in some cases limited and/or invasive. The genetic basis for some of these disorders has been identified, and with increased utilization of exome and whole genome sequencing even before lung biopsy, further insights into their genetic etiologies should become available.

Defining the Typical Course of Persistent Pulmonary Hypertension of the Newborn: When to Think Beyond Reversible Causes

OBJECTIVES

To describe the typical clinical course of reversible persistent pulmonary hypertension of the newborn (PPHN) from perinatal etiologies and compare that with the clinical course of PPHN due to underlying fetal developmental etiologies.

STUDY DESIGN

This was a single-center, retrospective cohort study of liveborn newborns either born or transferred to our facility for higher level of care between 2015 and 2020 with gestational age ≥35 weeks and a clinical diagnosis of PPHN in the electronic health record. Newborns with complex congenital heart disease and congenital diaphragmatic hernia were excluded. Using all data available at time of collection, newborns were stratified into 2 groups by PPHN etiology - perinatal and fetal developmental causes. Primary outcomes were age at initiation, discontinuation, and total duration of extracorporeal life support, mechanical ventilation, supplemental oxygen, inhaled nitric oxide, inotropic support, and prostaglandin E1. Our secondary outcome was age at echocardiographic resolution of pulmonary hypertension. Groups were compared by t-test. Time-to-event Kaplan Meier curves described and compared (log-rank test) discontinuation of each therapy.

RESULTS

Sixty-four (72%) newborns had perinatal etiologies whereas 24 (28%) had fetal developmental etiologies. The resolution of perinatal PPHN was more rapid compared with fetal developmental PPHN. By 10 days of age, more neonates were off inotropes (98% vs 29%, P < .01), decannulated from extracorporeal life support (100% vs 0%, P < .01), extubated (75% vs 37%, P < .01), and had echocardiographic resolution of PH (35% vs 7%, P = .02).

CONCLUSIONS

An atypical PPHN course, characterized by persistent targeted therapies in the second week of life, warrants further work-up for fetal developmental causes.

Neonatal-onset pulmonary alveolar proteinosis is a phenotype associated with poor outcomes in surfactant protein-C disorder

BACKGROUND

Surfactant protein C (SP-C) disorder is a major component of hereditary interstitial lung disease (HILD) among Japanese. The correlation between clinical outcomes and the phenotype/genotype of SP-C disorder has not been evaluated comprehensively. The current study aimed to evaluate the phenotype/genotype correlated with poor outcomes in patients with SP-C disorder.

METHODS

Sequencing analysis of SFTPC in 291 candidates with HILD was performed. The phenotype and genotype correlated with poor outcomes were examined. The log-rank test was used to compare the probability of good outcomes between two patient groups.

RESULTS

Twenty patients were diagnosed with SP-C disorder. Of nine patients with neonatal-onset disease, four and five presented with pulmonary alveolar proteinosis (PAP) and interstitial pneumonitis (IP), respectively. The remaining 11 patients with late-onset disease had IP. In total, four and 16 patients had PAP and IP phenotypes, respectively. Four of nine patients with neonatal-onset disease died, and one survived after lung transplant. Further, 1 of 11 patients with late-onset disease died. Four patients with neonatal-onset PAP had a significantly lower probability of good outcomes than the remaining patients. Two patients with neonatal-onset PAP had the p.Leu45Arg variant, one died and the another survived after lung transplant. Of eight patients with variants in the BRICHOS domain, one with frame shift variant located in exon 4, one with variant located at the splicing acceptor site of exon 4, and one with variant located at the splicing donor site of exon 4 died.

CONCLUSION

Neonatal-onset PAP was a phenotype predicting poor outcomes in patients with SP-C disorder. The p.Leu45Arg variant and splicing disorder of exon 4 might be genotypes predicting poor outcomes in patients with SP-C disorder.

Human pluripotent stem cell modeling of alveolar type 2 cell dysfunction caused by ABCA3 mutations

Mutations in ATP-binding cassette A3 (ABCA3), a phospholipid transporter critical for surfactant homeostasis in pulmonary alveolar type II epithelial cells (AEC2s), are the most common genetic causes of childhood interstitial lung disease (chILD). Treatments for patients with pathological variants of ABCA3 mutations are limited, in part due to a lack of understanding of disease pathogenesis resulting from an inability to access primary AEC2s from affected children. Here, we report the generation of AEC2s from affected patient induced pluripotent stem cells (iPSCs) carrying homozygous versions of multiple ABCA3 mutations. We generated syngeneic CRISPR/Cas9 gene-corrected and uncorrected iPSCs and ABCA3-mutant knockin ABCA3:GFP fusion reporter lines for in vitro disease modeling. We observed an expected decreased capacity for surfactant secretion in ABCA3-mutant iPSC-derived AEC2s (iAEC2s), but we also found an unexpected epithelial-intrinsic aberrant phenotype in mutant iAEC2s, presenting as diminished progenitor potential, increased NFκB signaling, and the production of pro-inflammatory cytokines. The ABCA3:GFP fusion reporter permitted mutant-specific, quantifiable characterization of lamellar body size and ABCA3 protein trafficking, functional features that are perturbed depending on ABCA3 mutation type. Our disease model provides a platform for understanding ABCA3 mutation-mediated mechanisms of alveolar epithelial cell dysfunction that may trigger chILD pathogenesis.

Lung biopsies in infants and children in critical care situation

INTRODUCTION

Lung biopsy is considered as the last step investigation for diagnosing lung diseases; however, its indication must be carefully balanced with its invasiveness. The present study aims to evaluate the diagnostic yield of lung biopsy in critically ill patients hospitalized in the pediatric intensive care unit (ICU).

MATERIAL AND METHODS

Children who underwent a lung biopsy in the ICU between 1995 and 2022 were included. Biopsies performed in the operating room and post-mortem biopsies were excluded.

RESULTS

Thirty-one patients were included, with a median age of 18 days (2 days to 10.8 years); 21 (67.7%) were newborns. All patients required invasive mechanical ventilation, 26 (89.7%) had a pulmonary hypertension, and 22 (70.9%) were placed under extracorporeal membrane oxygenation (ECMO). The lung biopsy led to a diagnosis in 81% of the patients. The diagnostic reliability seemed to decrease with age (95% in newborns, 71% in 1 month to 2 years and 0/3 patients aged over 2 years old). Diffuse developmental disorders of the lung accounted for 15 (49%) patients, primarily alveolar capillary dysplasia, followed by surfactant disorders in 5 (16%) patients. Complications occurred in 9/31 (29%) patients including eight under ECMO, with massive hemorrhages in seven cases.

DISCUSSION AND CONCLUSION

In critical situations, lung biopsy should be performed. Lung biopsy is a reliable diagnostic procedure for neonates in critical situation when a diffuse developmental disorder of the lung is suspected. The majority of lung biopsy complication was associated with the use of ECMO. The prospective evaluation of the complications of such procedure under ECMO, and particularly over 10 days of ECMO and in children over 2-year-old remains to be ascertained.

A promoterless AAV6.2FF-based lung gene editing platform for the correction of surfactant protein B deficiency

Surfactant protein B (SP-B) deficiency is a rare genetic disease that causes fatal respiratory failure within the first year of life. Currently, the only corrective treatment is lung transplantation. Here, we co-transduced the murine lung with adeno-associated virus 6.2FF (AAV6.2FF) vectors encoding a SaCas9-guide RNA nuclease or donor template to mediate insertion of promoterless reporter genes or the (murine) Sftpb gene in frame with the endogenous surfactant protein C (SP-C) gene, without disrupting SP-C expression. Intranasal administration of 3 × 1011 vg donor template and 1 × 1011 vg nuclease consistently edited approximately 6% of lung epithelial cells. Frequency of gene insertion increased in a dose-dependent manner, reaching 20%-25% editing efficiency with the highest donor template and nuclease doses tested. We next evaluated whether this promoterless gene editing platform could extend survival in the conditional SP-B knockout mouse model. Administration of 1 × 1012 vg SP-B-donor template and 5 × 1011 vg nuclease significantly extended median survival (p = 0.0034) from 5 days in the untreated off doxycycline group to 16 days in the donor AAV and nuclease group, with one gene-edited mouse living 243 days off doxycycline. This AAV6.2FF-based gene editing platform has the potential to correct SP-B deficiency, as well as other disorders of alveolar type II cells.

A rare presentation of childhood interstitial lung disease attributed to KDM3B gene mutation: a case report

Childhood Interstitial Lung Disease (chILD) encompasses various respiratory conditions affecting children's lung airspaces and tissues, with diverse causes. One rare cause involves structural vascular changes. We describe a case of a 10-year-old boy diagnosed with chILD who exhibited specific dysmorphic features, developmental delay, and intellectual disability. He was diagnosed with severe pulmonary arterial hypertension (PAH) due to venous thromboembolic disease, an unusual underlying condition for chILD. A Whole Exome Sequence showed mutations in KDM3B and SIN3A genes, respectively responsible for Diets-Jongmans syndrome (DIJOS) and Witteveen-Kolk syndrome (WITKOS). Both syndromes can explain our patient´s phenotype and KDM3B mutation has been previously described to be associated with PAH. Our case suggests a potential association between KDM3B mutation and PAH leading to chILD. It also enriches the knowledge of genotypic diversity in KDM3B and SIN3A genes as well as the spectrum of clinical associations with DIJOS and WITKOS syndromes.

Lung biopsy in infants with severe bronchopulmonary dysplasia

INTRODUCTION

Lung biopsy is infrequently performed in the population of infants with severe bronchopulmonary dysplasia (BPD). Yet, its presentation may overlap with other infant diffuse lung diseases, including those within the spectrum of childhood interstitial lung diseases (chILD). Lung biopsy might differentiate between these entities or identify those with an extremely poor prognosis. Both might alter the clinical management of some infants diagnosed with BPD.

METHODS

In this tertiary referral center, we drew on a retrospective cohort of 308 preterm infants with severe BPD. Of these, nine underwent lung biopsy between 2012 and 2017. We aimed to assess the indication for lung biopsy, the prior clinical history, safety of the procedure, and describe the biopsy findings. Finally, we considered management decisions in relation to the biopsy results in these patients.

RESULTS

All nine infants undergoing biopsy survived the procedure. The mean gestational age and birth weight of the nine patients were 30 ± 3 (range 27-34) weeks and 1421 ± 571 (range 611-2140) grams. All infants received serial echocardiograms to assess pulmonary hypertension, genetic testing, and computed tomography angiography (CTA) before biopsy. In all nine patients moderate to severe alveolar simplification was present and eight had some degree of pulmonary interstitial glycogenosis (PIG) ranging from focal to diffuse. Following biopsy, two infants with PIG received high dose systemic steroids and two separate infants had care redirected.

CONCLUSION

In our cohort, lung biopsy was safe and well tolerated. Findings from lung biopsy may aid decision making in selected patients as a part of a step-wise diagnostic algorithm.

Interstitial Lung Disease in Neonates: A Long Road Is Being Paved

Background: Interstitial lung disease (ILD) is one of the most difficult conditions in pulmonology due to difficulties in diagnosing, classifying, and treating this condition. They require invasive approaches to diagnose (e.g., lung biopsy), non-applicable methods (e.g., lung function tests in newborns), or potentially non-accessible methods (e.g., genetic testing in not-well-equipped facilities, and several weeks are required for results to be announced). They represent a heterogeneous group of diseases in which the alveolar epithelium, parenchyma, and capillaries of the lungs are damaged, which leads to changes in the pulmonary interstitium, proliferation of connective tissue, and thickening of the alveolar-capillary membranes and alveolar septa. These changes are accompanied by impaired oxygen diffusion, progressive respiratory failure, and radiographic signs of bilateral dissemination. Although adult and child classifications for ILD have evolved over the years, classification for ILD in neonates remains a challenge. Case presentation: Here we discuss ILD in neonates briefly, and report two rare cases of ILD (a male white neonate, two-day-old with fibrosing alveolitis, and another male white neonate, one-day old with desquamative interstitial pneumonitis), with these diagnoses initially thought to be presented only in adulthood. Lung biopsy and histopathological findings of the two neonates have shown mononuclear cells in the alveolar spaces, and thickening of the alveolar walls confirmed the diagnosis of fibrosing alveolitis in one neonate, and desquamation of the large mononuclear cells in the intra-alveolar space in the other neonate, with the diagnosis of desquamative interstitial pneumonitis being confirmed. Interstitial lung disease lacks a consensus guideline on classification and diagnosis in neonates, rendering it one of the greatest challenges to pediatricians and neonatologists with remarkable morbidity and mortality rates. Conclusions: Fibrosing alveolitis and desquamative interstitial pneumonitis (DIP) are not adult-only conditions, although rare in neonates, histopathological examination and clinical practice can confirm the diagnosis. Based on our clinical practice, prenatal and maternal conditions may serve as potential risk factors for developing IDL in neonates, and further studies are needed to prove this hypothesis.

Persistent Tachypnoea in Early Infancy: A Clinical Perspective

Tachypnoea in the newborn is common. It may arise from the many causes of the respiratory distress syndrome such as hyaline membrane disease, transient tachypnoea of the newborn, meconium aspiration etc. Congenital heart disease rarely presents with early tachypnoea on day one or two, in contrast to the early presentation of cyanosis, unless there is "pump" (ventricular) failure such as may occur in a cardiomyopathy/myocarditis, or as a result of severe obstruction to either ventricle. Space-occupying lesions within the chest, for example from a diaphragmatic hernia or a congenital cystic adenomatoid malformation, may present with early tachypnoea, as can a metabolic cause resulting in acidosis. The aim of this paper, however, is to focus on infants where the tachypnoea persists or develops beyond the newborn period, at times with minimal signs but occasionally with serious underlying pathology. They include causes that may have originated in the newborn but then persist; for example, arising from pulmonary hypoplasia or polycythemia. Many congenital cardiac abnormalities, particularly those causing left sided obstructive lesions, or those due to an increasing left to right shunt from large communications between the systemic and pulmonary circulations, need be considered. Respiratory causes, for example arising from aspiration, primary ciliary dyskinesia, cystic fibrosis, or interstitial lung disease, may lead to ongoing tachypnoea. Infective causes such as bronchiolitis or infantile wheeze generally are readily recognisable. Finally, there are a few infants who present with persistent tachypnoea over the first few weeks/months of their life who remain well and have normal investigations with the tachypnoea gradually resolving. How should one approach infants with persistent tachypnoea?

Molecular Function and Contribution of TBX4 in Development and Disease

Over the past decade, recognition of the profound impact of the TBX4 (T-box 4) gene, which encodes a member of the evolutionarily conserved family of T-box-containing transcription factors, on respiratory diseases has emerged. The developmental importance of TBX4 is emphasized by the association of TBX4 variants with congenital disorders involving respiratory and skeletal structures; however, the exact role of TBX4 in human development remains incompletely understood. Here, we discuss the developmental, tissue-specific, and pathological TBX4 functions identified through human and animal studies and review the published TBX4 variants resulting in variable disease phenotypes. We also outline future research directions to fill the gaps in our understanding of TBX4 function and of how TBX4 disruption affects development.

Diagnostic workup of childhood interstitial lung disease

Childhood interstitial lung diseases (chILDs) are rare and heterogeneous diseases with significant morbidity and mortality. An accurate and quick aetiological diagnosis may contribute to better management and personalised treatment. On behalf of the European Respiratory Society Clinical Research Collaboration for chILD (ERS CRC chILD-EU), this review summarises the roles of the general paediatrician, paediatric pulmonologists and expert centres in the complex diagnostic workup. Each patient's aetiological chILD diagnosis must be reached without prolonged delays in a stepwise approach from medical history, signs, symptoms, clinical tests and imaging, to advanced genetic analysis and specialised procedures including bronchoalveolar lavage and biopsy, if necessary. Finally, as medical progress is fast, the need to revisit a diagnosis of "undefined chILD" is stressed.

Disruption of Cdyl gene impairs mouse lung epithelium differentiation and maturation

CDYL is a chromodomain protein that has been identified as a transcriptional co-repressor that is primarily involved in the formation of repressor complexes which coordinate histone modifications to repress gene transcription. However, most functions and mechanisms of action of the CDYL protein are unknown. In this study, we show that Cdyl-/- mice died of respiratory distress immediately at birth because of distinct abnormalities in distal lung morphogenesis which was characterized by thickened septal and expiratory alveolus atelectasis. Furthermore, Cdyl deletion in mice led to excessive proliferation of immature epithelial cells and an arrest in alveolar epithelium cell differentiation in late gestation which were associated with decreased secretion of mature surfactant proteins in alveolus. Microarray analysis showed that Cdyl gene deletion influenced the expression of genes regulating neuroactive ligand-receptor interactions, cell adhesion, and cell cycle. We validated that Cdyl repressed the transcriptional activity of Cks1 in vitro. In conclusion, Cdyl gene participates in the perinatal respiratory epithelium differentiation and maturation that is important for normal lung function at birth.

Congenital Cystic Adenomatoid Malformation (CCAM) Type II: A Rare Case of Sudden Infant Death

Congenital cystic adenomatoid malformation (CCAM) is a developmental lesion of the lungs and terminal respiratory structures, which is characterized by pseudocysts, lesions, and cystically dilated airways. CCAM is also known as congenital pulmonary airway malformation (CPAM). Various classification systems for CCAM have been described, and based on a recent classification, CCAMs are classified morphologically into five different types (Type 0, I, II, III, and IV) based on lesion sizes. The most common manifestation of CCAM in neonates and children is respiratory distress (RD). Spontaneous pneumothorax is a rare manifestation of CCAM. In this case report, we discuss a CCAM type-II case of a 38-day-old female infant with a radiological post-mortem diagnosis of a large left-side spontaneous pneumothorax. The gross examination of the lungs revealed multiple emphysematous air bubbles up to 0.5 cm in diameter, and the histological examination revealed focal pleural fibrosis, accompanied by thickened septa and atelectasis. In this scenario, the routine use of prenatal ultrasonography would be important to obtain a timely prenatal diagnosis. At the same time, improvements in surgical techniques, as well as greatly improved imaging techniques, have improved the outcome of these patients. Finally, it is important to remark on the importance of autopsy in the case of sudden infant death with a suspected CCAM.

Interstitial Lung Disease in Children: “Specific Conditions of Undefined Etiology” Becoming Clearer

Background: Children’s interstitial lung disease (chILD) is a rare group of pediatric lung diseases affecting the lung interstitium diffusely. In this work, we focused our attention on a specific infant group of chILD, also known as “specific conditions of undefined aetiology”, including pulmonary interstitial glycogenosis (PIG) and neuroendocrine cell hyperplasia of infancy (NEHI). Methods: PubMed was searched to conduct this narrative review. We searched for articles in English using the following keywords: (1) neuroendocrine cell hyperplasia of infancy; (2) NEHI; (3) pulmonary interstitial glycogenosis; (4) PIG; (5) chILD. Results: An increasing interest and insight into these two conditions have been reported. The updated literature suggests that it is possible to look at these disorders as a continuum of diseases, rather than two different entities, since they share a pulmonary dysmaturity. Conclusions: NEHI and PIG are featured by dysmaturity of airway development and consequent respiratory distress. Understanding the underlying pathogenic mechanisms would lead to identifying new targeted therapies to ameliorate the mortality and morbidity of these rare conditions.

Haploinsufficiencies of FOXF1, FOXC2 and FOXL1 genes originated from deleted 16q24.1q24.2 fragment related with alveolar capillary dysplasia with misalignment of pulmonary veins and lymphedema-distichiasis syndrome: relationship to phenotype

Objective

We describe a fetus with a 2.12-Mb terminal deleted fragment in 16q associated with alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) and lymphedema-distichiasis syndrome (LDS) and intend to provide a comprehensive prenatal management strategy for the fetuses with ACDMPV and LDS through reviewing other similar published studies.

Methods

The fetus presented a series of diverse structural malformations including congenital cardiovascular, genitourinary and gastro-intestinal anomalies in ultrasound at 23 + 5 weeks of gestation (GA). Amniocentesis was conducted for karyotype analysis and copy number variation sequencing (CNV-seq) after informed consent.

Results

The fetal karyotype was 46,XX, however the result of CNV-seq showed an approximately 2.12-Mb deletion in 16q24.1q24.2 (85220000-87340000) × 1 indicating pathogenicity.

Conclusion

Genomic testing should be recommend as a first line diagnostic tool for suspected ACDMPV and/or LDS or other genetic syndromes for the fetuses with structural abnormalities in clinical practice.

Variable expressivity in a four-generation ACDMPV family with a non-coding hypermorphic SNV in trans to the frameshifting FOXF1 variant

Heterozygous single nucleotide variants (SNVs) or copy-number variant deletions involving FOXF1 or its distant lung-specific enhancer on chromosome 16q24.1 have been identified in 80-90% of patients with Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV), a lethal neonatal lung developmental disorder. We describe a four-generation family with a deceased ACDMPV neonate, her sibling from the electively terminated pregnancy, healthy mother with a history of pulmonary arterial hypertension (PAH), an unaffected aunt, an aunt deceased due to findings consistent with ACDMPV, and a reportedly unaffected grandmother, all with the frameshifting variant c.881_902dup (p.Gly302Profs*46) in FOXF1, and a deceased great-grandmother with a history of PAH. Genome sequencing analyses in the proband's unaffected mother revealed a non-coding putative regulatory SNV rs560517434-A within the lung-specific distant FOXF1 enhancer in trans to the FOXF1 frameshift mutation. Functional testing of this variant using an in vitro luciferase reporter assay showed that it increased FOXF1 promoter activity 10-fold. Our studies further demonstrate that non-coding SNVs in the FOXF1 enhancer region can rescue the lethal ACDMPV phenotype and support the compound inheritance gene dosage model.

Distribution of Presepsin, Krebs von den Lungen 6, and Surfactant Protein A in Umbilical Cord Blood

Presepsin is an early indicator of infection, and Krebs von den Lungen 6 (KL-6) and Surfactant Protein A (SP-A) are related to the pathogenesis of pulmonary infection and fibrosis. This study aimed to establish reference intervals (RIs) of presepsin, KL-6, and SP-A levels and to evaluate the possible influence of neonatal and maternal factors on presepsin, KL-6, and SP-A levels in umbilical cord blood (UCB). Among a total of 613 UCB samples, the outliers were removed. The RIs for presepsin, KL-6, and SP-A levels were defined using non-parametric percentile methods according to the Clinical and Laboratory Standards Institute guidelines (EP28-A3C). These levels were analyzed according to neonatal and maternal factors: neonatal sex, gestational age (GA), birth weight (BW), Apgar score, delivery mode, the presence of premature rupture of membranes (PROM), gestational diabetes mellitus (GDM), and pre-eclampsia. Presepsin, KL-6, and SP-A levels showed non-parametric distributions and left-skewed histograms. The RIs of presepsin, KL-6, and SP-A levels were 64.9–428.3 pg/mL, 43.0–172.0 U/mL, and 2.1–36.1 ng/mL, respectively. Presepsin, KL-6, and SP-A levels did not show significant differences according to sex, GA, BW, Apgar score, delivery mode, PROM, GDM, and pre-eclampsia. The median level and 97.5th centile RI of KL-6 showed a slight increase with increased GA. We established RIs for presepsin, KL-6, and SP-A levels in large-scaled UCB samples. Further investigation would be needed to determine the clinical significance.

The role of exome sequencing in childhood interstitial or diffuse lung disease

BACKGROUND

Children's interstitial and diffuse lung disease (chILD) is a complex heterogeneous group of lung disorders. Gene panel approaches have a reported diagnostic yield of ~ 12%. No data currently exist using trio exome sequencing as the standard diagnostic modality. We assessed the diagnostic utility of using trio exome sequencing in chILD. We prospectively enrolled children meeting specified clinical criteria between 2016 and 2020 from 16 Australian hospitals. Exome sequencing was performed with analysis of an initial gene panel followed by trio exome analysis. A subset of critically ill infants underwent ultra-rapid trio exome sequencing as first-line test.

RESULTS

36 patients [median (range) age 0.34 years (0.02-11.46); 11F] were recruited from multiple States and Territories. Five patients had clinically significant likely pathogenic/pathogenic variants (RARB, RPL15, CTCF, RFXANK, TBX4) and one patient had a variant of uncertain significance (VIP) suspected to contribute to their clinical phenotype, with VIP being a novel gene candidate.

CONCLUSIONS

Trio exomes (6/36; 16.7%) had a better diagnostic rate than gene panel (1/36; 2.8%), due to the ability to consider a broader range of underlying conditions. However, the aetiology of chILD in most cases remained undetermined, likely reflecting the interplay between low penetrant genetic and environmental factors.

Endotypes of Prematurity and Phenotypes of Bronchopulmonary Dysplasia: Toward Personalized Neonatology

Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, is increasingly recognized as the consequence of a pathological reparative response of the developing lung to both antenatal and postnatal injury. According to this view, the pathogenesis of BPD is multifactorial and heterogeneous with different patterns of antenatal stress (endotypes) that combine with varying postnatal insults and might distinctively damage the development of airways, lung parenchyma, interstitium, lymphatic system, and pulmonary vasculature. This results in different clinical phenotypes of BPD. There is no clear consensus on which are the endotypes of prematurity but the combination of clinical information with placental and bacteriological data enables the identification of two main pathways leading to birth before 32 weeks of gestation: (1) infection/inflammation and (2) dysfunctional placentation. Regarding BPD phenotypes, the following have been proposed: parenchymal, peripheral airway, central airway, interstitial, congestive, vascular, and mixed phenotype. In line with the approach of personalized medicine, endotyping prematurity and phenotyping BPD will facilitate the design of more targeted therapeutic and prognostic approaches.

Case Report: Report of Two Cases of Interstitial Lung Disease Caused by Novel Compound Heterozygous Variants in the ABCA3 Gene

Interstitial lung disease (ILD) is a heterogeneous group of pulmonary disorders involving the lung interstitium and distal airways, also known as diffuse lung disease. The genetic defects resulting in alveolar surfactant protein dysfunction are a rare cause of ILD in pediatric patients. We report two unrelated pediatric patients with shortness of breath, dyspnea and hypoxemia, and the chest CT findings including patchy ground-glass opacity in both lung fields, suggestive of diffuse ILD. One patient was a full-term male infant who had shortness of breath a few hours after the birth, and then developed into severe respiratory distress syndrome (RDS). Whole exome sequencing revealed novel compound heterozygous variants in the ABCA3 gene (NM_001,089.3): paternally inherited c.4035+5G > A and c.668T > C (p.M223T), and maternally inherited c.1285+4A > C. The second patient was a 34-month-old boy with onset of chronic repeated cough and hypoxemia at 9 months of age. We unveiled novel compound heterozygous ABCA3 variants (c.704T > C, p.F235S; c.4037_4040del, p.T1346Nfs*15) in this patient. Surfactant protein dysfunction due to bi-allelic mutations in the ABCA3 gene was the cause of ILD in two patients. The novel mutations found in this study expanded the spectrum of known mutations in the ABCA3 gene.

Interstitial lung disease in infancy and early childhood: a clinicopathological primer

Children's interstitial lung disease (chILD) encompasses a wide and heterogeneous spectrum of diseases substantially different from that of adults. Established classification systems divide chILD into conditions more prevalent in infancy and other conditions occurring at any age. This categorisation is based on a multidisciplinary approach including clinical, radiological, genetic and histological findings. The diagnostic evaluation may include lung biopsies if other diagnostic approaches failed to identify a precise chILD entity, or if severe or refractory respiratory distress of unknown cause is present. As the majority of children will be evaluated and diagnosed outside of specialist centres, this review summarises relevant clinical, genetic and histological findings of chILD to provide assistance in clinical assessment and rational diagnostics.

ILD of childhood is comparable by name only to lung disease in adults. A dedicated interdisciplinary team is required to achieve the best possible outcome. This review summarises the current clinicopathological criteria and associated genetic alterations.https://bit.ly/3mpxI3b

Congenital interstitial lung diseases: What the anesthesiologist needs to know

Congenital interstitial lung diseases can affect both adults and children. Pediatric congenital interstitial lung diseases generally carry high risk for morbidly and mortality and include congenital alveolar capillary dysplasia with misalignment of pulmonary veins, congenital alveolar dysplasia, acinar dysplasia, congenital pulmonary lymphangiectasis, diffuse pulmonary lymphangiomatosis, neuroendocrine cell hyperplasia of infancy, pulmonary hemosiderosis, pulmonary alveolar proteinosis, and pulmonary interstitial glycogenosis. Given their usual non-specific clinical presentation, they are frequently misdiagnosed and recognized late, particularly in children who have been apparently healthy for several years (eg, diffuse pulmonary lymphangiomatosis). Some diseases have a very poor prognosis, whereas others have a benign course with appropriate treatment. The current manuscript reviews congenital interstitial lung diseases that typically affect neonates and young children and may be encountered by the pediatric anesthesiologist.

Treatment of Respiratory Distress Syndrome with Single Recombinant Polypeptides that Combine Features of SP-B and SP-C

Treatment of respiratory distress syndrome (RDS) with surfactant replacement therapy in prematurely born infants was introduced more than 30 years ago; however, the surfactant preparations currently in clinical use are extracts from animal lungs. A synthetic surfactant that matches the currently used nature-derived surfactant preparations and can be produced in a cost-efficient manner would enable worldwide treatment of neonatal RDS and could also be tested against lung diseases in adults. The major challenge in developing fully functional synthetic surfactant preparations is to recapitulate the properties of the hydrophobic lung surfactant proteins B (SP-B) and SP-C. Here, we have designed single polypeptides that combine properties of SP-B and SP-C and produced them recombinantly using a novel solubility tag based on spider silk production. These Combo peptides mixed with phospholipids are as efficient as nature-derived surfactant preparations against neonatal RDS in premature rabbit fetuses.

Childhood Interstitial Lung Disease Masquerading as Post COVID-19 Respiratory Distress

Childhood interstitial lung diseases (chILD) are a set of illnesses affecting the bronchoalveolar spaces and the cellular compartment of the lungs. In the neonatal period, they are mainly classified under disorders of development, growth, surfactant dysfunction, and others of unknown causes distinctive in infancy. One of the most common causes is the deficiency of triphosphate binding cassette transporter A3 (ABCA3) protein. It activates impairment in the function of surfactants, resulting in respiratory distress in term infants, which is lethal in many cases and in some other cases leads to interstitial lung disease.

We herein present a case of a 14-month-old boy with a peculiar case of ABCA3 protein deficiency that was masked at birth with COVID-19 infection and then presented with shortness of breath and poor feeding at the age of three months. The child was treated with macrolides, steroids, and hydroxychloroquine, with which he survived beyond the age of one year.

A novel synonymous ABCA3 variant identified in a Chinese family with lethal neonatal respiratory failure

Background

Lethal respiratory failure is primarily caused by a deficiency of pulmonary surfactant, and is the main cause of neonatal death among preterm infants. Pulmonary surfactant metabolism dysfunction caused by variants in the ABCA3 gene is a rare disease with very poor prognosis. Currently, the mechanisms associated with some ABCA3 variants have been determined, including protein mistrafficking and impaired phospholipid transport. However, some novel variants and their underlying pathogenesis has not been fully elucidated yet. In this study we aimed to identify the genetic features in a family with lethal respiratory failure.

Methods

We studied members of two generations of a Chinese family, including a female proband, her parents, her monozygotic twin sister, and her older sister. Trio whole exome sequencing (WES) were used on the proband and her parents to identify the ABCA3 variants. Sanger sequencing and real-time quantitative polymerase chain reaction (PCR) were used on the monozygotic twin sister of proband to validate the ABCA3 synonymous variant and exon deletion, respectively. The potential pathogenicity of the identified synonymous variant was predicted using the splice site algorithms dbscSNV11_AdaBoost, dbscSNV11_RandomForest, and Human Splicing Finder (HSF).

Results

All patients showed severe respiratory distress, which could not be relieved by mechanical ventilation, supplementation of surfactant, or steroid therapy, and died at an early age. WES analysis revealed that the proband had compound heterozygous ABCA3 variants, including a novel synonymous variant c.G873A (p.Lys291Lys) in exon 8 inherited from the mother, and a heterozygous deletion of exons 4–7 inherited from the father. The synonymous variant was consistently predicted to be a cryptic splice donor site that may lead to aberrant splicing of the pre-mRNA by three different splice site algorithms. The deletion of exons 4–7 of the ABCA3 gene was determined to be a likely pathogenic variant. The variants were confirmed in the monozygotic twin sister of proband by Sanger sequencing and qPCR respectively. The older sister of proband was not available to determine if she also carried both ABCA3 variants, but it is highly likely based on her clinical course.

Conclusions

We identified a novel synonymous variant and a deletion in the ABCA3 gene that may be responsible for the pathogenesis in patients in this family. These results add to the known mutational spectrum of the ABCA3 gene. The study of ABCA3 variants may be helpful for the implementation of patient-specific therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01098-4.

Possible association between SP-C mutations and lung cancer: Two case reports and review of literature

Surfactant protein C (SP-C) is one of four surfactant proteins produced by type II pneumocytes. Mutations in surfactant protein A are strongly associated with development of lung cancer. Mutations in the SP-C gene are rare and are associated with interstitial lung disease in the pediatric age group. We describe two patients with SP-C mutations who developed lung cancer. Both patients had concurrent interstitial lung disease, although the clinical phenotype was variable. In both cases, mutations were in translated region of the SP-C gene; one in the BRICHOS domain and the other in the transmembrane domain. Our paper suggests that patients with SP-C mutations can be at increased risk for the development of lung cancer, and it's reasonable to follow them routinely.

Severe herpes virus 6 interstitial pneumonia in an infant with three variants in genes predisposing to lung disease

Infections due to human herpesvirus 6 (HHV-6) are frequent during early childhood. Usually, they have a favorable clinical course. Conversely, HHV-6 congenital infections occur in about 1% of neonates and may present with more severe clinical pictures. HHV-6 can be found in lung tissues and bronchoalveolar lavage (BAL) samples from patients with pneumonia and in immunocompromised patients can cause mild to severe pneumonia. In neonates, the role of HHV-6 in the genesis of severe pneumonia is poorly defined still now. We describe a healthy infant with a late-onset (15 days of life) severe interstitial pneumonia and heavy HHV-6 genome load, persistently detected in its BAL fluid. The baby underwent high-frequency oscillatory ventilation, hydroxychloroquine, steroids, and ganciclovir for 6 weeks and at 9 months she died. Next-generation sequencing of genes known to cause neonatal respiratory insufficiency revealed the presence of a "probably pathogenetic" heterozygous variant in the autosomal recessive DRC1 gene, a heterozygous variant of unknown significance (VUS) in the autosomal recessive RSPH9 gene, and a heterozygous VUS in the autosomal recessive MUC5B gene. HHV-6 infection should be considered in the differential diagnosis of late-onset severe respiratory distress in neonates and the co-occurrence of genetic predisposing factors or modifiers should be tested by specific molecular techniques. The intensity of HHV-6 genome load in BAL fluid could be an indicator of the response to antiviral therapy.

Non-immune hydrops fetalis secondary to congenital chylothorax with diffuse interstitial lung disease: a diagnostic conundrum

A Chinese male infant was born at 35 weeks weighing 2935 g to a mother with polyhydramnios and prenatal hydrops fetalis. He developed marked respiratory distress secondary to bilateral congenital chylothorax and required pleural drainage, high frequency oscillation and inhaled nitric oxide therapy. He was extubated to non-invasive ventilation by day 14. There was no bacterial or intrauterine infection, haematologic, chromosomal or cardiac disorder. He was exclusively fed medium-chain triglyceride formula. High-resolution CT showed diffuse interstitial lung disease. He received a dexamethasone course for chronic lung disease to facilitate supplemental oxygen weaning. A multidisciplinary team comprising neonatology, pulmonology, haematology, interventional radiology and thoracic surgery considered congenital pulmonary lymphangiectasia as the most likely diagnosis and advised open lung biopsy, lymphangiography or scintigraphy for diagnostic confirmation should symptoms of chylothorax recur. Fortunately, he was weaned off oxygen at 5 months of life, and tolerated human milk challenge at 6 months of life and grew well.

Oliver McFarlane syndrome: two new cases and a review of the literature

BACKGROUND

Oliver McFarlane syndrome is a rare syndrome. Clinical presentations include trichomegaly, chorioretinal degeneration, pituitary hormone deficits, and neurological manifestations. Genetic analysis has recently placed this syndrome within the group of PNPLA6-related disorders. Here, we describe two new individuals and review the previously published cases.

MATERIALS AND METHODS

Clinical investigations were carried out in accordance with local guidelines and clinical information was retrieved from medical records. Genetic studies were carried out using next-generation sequencing based clinical exome sequencing. A PubMed literature search was performed with a review of the published clinical cases of Oliver McFarlane syndrome.

RESULTS

Our first individual was a 36-year-old woman with 32 years of follow up and our second individual was a 3-year-old boy. Both individuals were born preterm and presented with prolonged neonatal respiratory distress, trichomegaly, early growth retardation, retinopathy and sparse depigmented hair. So far, none of our cases have demonstrated cognitive impairment or progressive neurological symptoms, but the child revealed persistent abnormal lung structure. Both individuals were compound heterozygous for pathogenic PNPLA6 variants, one of which was novel. We found other 31 clinically documented published cases.

CONCLUSIONS

Our two new unrelated cases of Oliver McFarlane Syndrome demonstrate early ophthalmological and systemic findings of this rare syndrome and the progressive nature of the retinopathy with a long follow-up. PNPLA6-related disorders are a phenotypically highly heterogenous group where alterations in the phosphatidylcholine metabolism can lead to manifestations in different tissues with no clear genotype-phenotype correlation.

Hydroxychloroquine, a successful treatment for lung disease in ABCA3 deficiency gene mutation: a case report

Background

Pulmonary surfactant is a complex mixture of lipids and specific proteins that stabilizes the alveoli at the end of expiration. Mutations in the gene coding for the triphosphate binding cassette transporter A3 (ABCA3), which facilitates the transfer of lipids to lamellar bodies, constitute the most frequent genetic cause of severe neonatal respiratory distress syndrome and chronic interstitial lung disease in children. Hydroxychloroquine can be used as an effective treatment for this rare severe condition.

Case presentation

We report a late preterm Bosnian baby boy (36 weeks) who suffered from a severe form of respiratory distress syndrome with poor response to intensive conventional management and whole exome sequencing revealed homozygous ABCA3 mis-sense mutation. The baby showed remarkable improvement of the respiratory condition after the initiation of Hydroxychloroquine, Azithromycin and Corticosteroids with the continuation of Hydroxychloroquine as a monotherapy till after discharge from the hospital.

Conclusion

Outcome in patients with ABCA3 mutations is variable ranging from severe irreversible respiratory failure in early infancy to chronic interstitial lung disease in childhood (ChILD) usually with the need for lung transplantation in many patients surviving this rare disorder. Hydroxychloroquine through its anti-inflammatory effects or alteration of intra-cellular metabolism may have an effect in treating cases of ABCA3 gene mutations.

[Interstitial lung disease in infancy and early childhood]

Diffuse interstitial lung disease of infancy (chILD) shows a spectrum of disease substantially different from that of adults. Established classification systems divide chILD into conditions that are more prevalent in infancy and conditions that occur at any age. The classification is based on a multidisciplinary approach including clinical, radiological, genetic, and histological findings. Lung biopsies become necessary if other diagnostic investigations have not identified a precise chILD or if severe or refractory respiratory distress of unknown cause is present. As the majority of pediatric lung biopsies will be received first by pathologists outside of specialist centers this review summarizes relevant clinical and histological findings of chILD.

Looking at the developing lung in single-cell resolution

Lung development is a complicated and delicate process, facilitated by spatially and temporarily coordinated cross talk of up to 40 cell types. Developmental origin and heterogeneity of lung cell lineages in context of lung development have been a focus of research efforts for decades. Bulk RNA and protein measurements, RNA and protein labeling, and lineage tracing techniques have been traditionally employed. However, the complex and heterogeneous nature of lung tissue presents a particular challenge when identifying subtle changes in gene expression in individual cell types. Rapidly developing single-cell RNA sequencing (scRNA-seq) techniques allow for unbiased and robust assessment of complex cellular dynamics during biological processes in unprecedented ways. Discovered a decade ago, scRNA-seq has been applied in respiratory research to understand lung cellular composition and to identify novel cell types. Still, very few studies to date have addressed the single-cell transcriptome in healthy or aberrantly developing lung. In this review, we discuss principal discoveries with scRNA-seq in the field of prenatal and postnatal lung development. In addition, we examine challenges and expectations, and propose future steps associated with the use of scRNA-seq to study developmental lung diseases.

The Impact of Rapid Exome Sequencing on Medical Management of Critically Ill Children

OBJECTIVES

To evaluate the clinical usefulness of rapid exome sequencing (rES) in critically ill children with likely genetic disease using a standardized process at a single institution. To provide evidence that rES with should become standard of care for this patient population.

STUDY DESIGN

We implemented a process to provide clinical-grade rES to eligible children at a single institution. Eligibility included (a) recommendation of rES by a consulting geneticist, (b) monogenic disorder suspected, (c) rapid diagnosis predicted to affect inpatient management, (d) pretest counseling provided by an appropriate provider, and (e) unanimous approval by a committee of 4 geneticists. Trio exome sequencing was sent to a reference laboratory that provided verbal report within 7-10 days. Clinical outcomes related to rES were prospectively collected. Input from geneticists, genetic counselors, pathologists, neonatologists, and critical care pediatricians was collected to identify changes in management related to rES.

RESULTS

There were 54 patients who were eligible for rES over a 34-month study period. Of these patients, 46 underwent rES, 24 of whom (52%) had at least 1 change in management related to rES. In 20 patients (43%), a molecular diagnosis was achieved, demonstrating that nondiagnostic exomes could change medical management in some cases. Overall, 84% of patients were under 1 month old at rES request and the mean turnaround time was 9 days.

CONCLUSIONS

rES testing has a significant impact on the management of critically ill children with suspected monogenic disease and should be considered standard of care for tertiary institutions who can provide coordinated genetics expertise.

Novel homozygous missense mutation in ABCA3 protein leading to severe respiratory distress in term infant

The term baby presented with respiratory distress with X-ray pictures consistent as hyaline membrane disease (HMD). Baby was ventilated and treated with surfactant. Because of the persistence of high ventilation needs with X-ray pictures consistent with HMD with a transient response to surfactant every time, the possibility of an inherited disorder of surfactant metabolism was kept. Whole-exome sequencing revealed a novel homozygous missense mutation in the gene for ATP binding cassette transporter protein A3. The baby died after 100 days of ventilation.

A Newly Observed Mutation of the ABCA3 Gene Causing Lethal Respiratory Failure of a Full-Term Newborn: A Case Report

Respiratory distress syndrome caused by a secondary surfactant deficiency is one of the most common diagnoses requiring admission to the Neonatal Intensive Care Unit. We illustrate the case of a term female newborn without prenatal and peripartal risks. There had been significant signs of respiratory distress 4 h after delivery. The condition gradually worsened to the point of needing oscillatory ventilation. The most common infectious and non-infectious causes were excluded. Considering the course of illness, a congenital surfactant deficiency was suspected. There nevertheless was no significant improvement after administration of surfactant. Following a short period of palliative care, the child died at 34 days of age due to respiratory failure. DNA diagnostics revealed compound heterozygosity of ABCA3 functional mutations leading to the p.Pro147Leu and p.Pro246Leu exchanges. The second identified mutation of ABCA3 c.737C>T had not to date been described in connection with primary surfactant deficiency.

Recognizing genetic disease: A key aspect of pediatric pulmonary care

Advancement in technology has improved recognition of genetic etiologies of disease, which has impacted diagnosis and management of rare disease patients in the pediatric pulmonary clinic. This review provides an overview of genetic conditions that are likely to present with pulmonary features and require extensive care by the pediatric pulmonologist. Increased familiarity with these conditions allows for improved care of these patients by reducing time to diagnosis, tailoring management, and prompting further investigation into these disorders.

Interstitial lung diseases in children

Interstitial lung disease (ILD) in children (chILD) is a heterogeneous group of rare respiratory disorders that are mostly chronic and associated with high morbidity and mortality. The pathogenesis of the various chILD is complex and the diseases share common features of inflammatory and fibrotic changes of the lung parenchyma that impair gas exchanges. The etiologies of chILD are numerous. In this review, we chose to classify them as ILD related to exposure/environment insults, ILD related to systemic and immunological diseases, ILD related to primary lung parenchyma dysfunctions and ILD specific to infancy. A growing part of the etiologic spectrum of chILD is being attributed to molecular defects. Currently, the main genetic mutations associated with chILD are identified in the surfactant genes SFTPA1, SFTPA2, SFTPB, SFTPC, ABCA3 and NKX2-1. Other genetic contributors include mutations in MARS, CSF2RA and CSF2RB in pulmonary alveolar proteinosis, and mutations in TMEM173 and COPA in specific auto-inflammatory forms of chILD. However, only few genotype-phenotype correlations could be identified so far. Herein, information is provided about the clinical presentation and the diagnosis approach of chILD. Despite improvements in patient management, the therapeutic strategies are still relying mostly on corticosteroids although specific therapies are emerging. Larger longitudinal cohorts of patients are being gathered through ongoing international collaborations to improve disease knowledge and targeted therapies. Thus, it is expected that children with ILD will be able to reach the adulthood transition in a better condition.

Clinical, Histopathological, and Molecular Diagnostics in Lethal Lung Developmental Disorders

Lethal lung developmental disorders are a rare but important group of pediatric diffuse lung diseases presenting with neonatal respiratory failure. On the basis of histopathological appearance at lung biopsy or autopsy, they have been termed: alveolar capillary dysplasia with misalignment of the pulmonary veins, acinar dysplasia, congenital alveolar dysplasia, and other unspecified primary pulmonary hypoplasias. However, the histopathological continuum in these lethal developmental disorders has made accurate diagnosis challenging, which has implications for recurrence risk. Over the past decade, genetic studies in infants with alveolar capillary dysplasia with misalignment of the pulmonary veins have revealed the causative role of the dosage-sensitive FOXF1 gene and its noncoding regulatory variants in the distant lung-specific enhancer at chromosome 16q24.1. In contrast, the molecular bases of acinar dysplasia and congenital alveolar dysplasia have remained poorly understood. Most recently, disruption of the TBX4-FGF10-FGFR2 epithelial-mesenchymal signaling pathway has been reported in patients with these lethal pulmonary dysplasias. Application of next-generation sequencing techniques, including exome sequencing and whole-genome sequencing, has demonstrated their complex compound inheritance. These data indicate that noncoding regulatory elements play a critical role in lung development in humans. We propose that for more precise lethal lung developmental disorder diagnosis, a diagnostic pathway including whole-genome sequencing should be implemented.

Approaching Clinical Trials in Childhood Interstitial Lung Disease and Pediatric Pulmonary Fibrosis

Childhood interstitial lung disease (chILD) comprises a spectrum of rare diffuse lung disorders. chILD is heterogeneous in origin, with different disease manifestations occurring in the context of ongoing lung development. The large number of disorders in chILD, in combination with the rarity of each diagnosis, has hampered scientific and clinical progress within the field. Epidemiologic and natural history data are limited. The prognosis varies depending on the etiology, with some forms progressing to lung transplant or death. There are limited treatment options for patients with chILD. Although U.S. Food and Drug Administration-approved treatments are now available for adult patients with idiopathic pulmonary fibrosis, no clinical trials have been conducted in a pediatric population using agents designed to treat lung fibrosis. This review will focus on progressive chILD disorders and on the urgent need for meaningful objective outcome measures to define, detect, and monitor fibrosis in children.

Recessive missense LAMP3 variant associated with defect in lamellar body biogenesis and fatal neonatal interstitial lung disease in dogs

Neonatal interstitial lung diseases due to abnormal surfactant biogenesis are rare in humans and have never been reported as a spontaneous disorder in animals. We describe here a novel lung disorder in Airedale Terrier (AT) dogs with clinical symptoms and pathology similar to the most severe neonatal forms of human surfactant deficiency. Lethal hypoxic respiratory distress and failure occurred within the first days or weeks of life in the affected puppies. Transmission electron microscopy of the affected lungs revealed maturation arrest in the formation of lamellar bodies (LBs) in the alveolar epithelial type II (AECII) cells. The secretory organelles were small and contained fewer lamellae, often in combination with small vesicles surrounded by an occasionally disrupted common limiting membrane. A combined approach of genome-wide association study and whole exome sequencing identified a recessive variant, c.1159G>A, p.(E387K), in LAMP3, a limiting membrane protein of the cytoplasmic surfactant organelles in AECII cells. The substitution resides in the LAMP domain adjacent to a conserved disulfide bond. In summary, this study describes a novel interstitial lung disease in dogs, identifies a new candidate gene for human surfactant dysfunction and brings important insights into the essential role of LAMP3 in the process of the LB formation.

Persistent Respiratory Distress in the Term Neonate: Genetic Surfactant Deficiency Diseases

Respiratory distress is one of the most common clinical presentations in newborns requiring admission to a Neonatal Intensive Care Unit (NICU). Many of these infants develop respiratory distress secondary to surfactant deficiency, which causes an interstitial lung disease that can occur in both preterm and term infants. Pulmonary surfactant is a protein and lipid mixture made by type II alveolar cells, which reduces alveolar surface tension and prevents atelectasis. The etiology of surfactant deficiency in preterm infants is pulmonary immaturity and inadequate production. Term infants may develop respiratory insufficiency secondary to inadequate surfactant, either from exposure to factors that delay surfactant synthesis (such as maternal diabetes) or from dysfunctional surfactant arising from a genetic mutation. The genetics of surfactant deficiencies are very complex. Some mutations are lethal in the neonatal period, while others cause a wide range of illness severity from infancy to adulthood. Genes that have been implicated in surfactant deficiency include SFTPA1, SFTPA2, SFTPB, SFTPC, and SFTPD (which encode for surfactant proteins A, B, C, and D, respectively); ABCA3 (crucial for surfactant packaging and secretion); and NKX2 (a transcription factor that regulates the expression of the surfactant proteins in lung tissue). This article discusses the interplay between the genotypes and phenotypes of newborns with surfactant deficiency to assist clinicians in determining which patients warrant a genetic evaluation.

Childhood diffuse parenchymal lung diseases: We need a new classification

INTRODUCTION

Childhood diffuse parenchymal lung diseases (DPLD) are a heterogeneous group of respiratory disorders of both known and unknown causes that share common histological features. To date, there is not an exact consensus about the terminology, classification, therapy and follow up of this disease because of its rarity and wide clinical spectrum.

OBJECTIVES

In this study, we tried to classify our DPLD patients according to the last classification scheme (chILD Network Classification).

METHODS

The files of the children diagnosed with DPLD at our university hospital between 1974 and 2012 were retrospectively investigated. Clinical features, laboratory, radiological and histopathological findings, therapy and follow-up outcomes of these patients were recorded and evaluated according to the actual information and definitions.

RESULTS

We described 130 DPLD patients, the largest childhood DPLD series from a single center, classified in 16 distinct groups according to their diagnosis. Our largest group in this serie is pulmonary hemosiderosis (28.5%); idiopathic interstitial pneumonias, pulmonary hemosiderosis, sarcoidosis and lipid storage diseases with lung involvement represent the 70% of the diagnoses. When we classified our patients according to the chILD Network Classification; patients with idiopathic interstitial pneumonia older than 2 years, idiopathic pulmonary hemosiderosis, pulmonary alveolar microlithiasis and diffuse chondroid malformation of the lung stayed out of this classification.

CONCLUSION

To ensure a consensus about the therapy and follow up, we have to make revisions and reorganisations on the DPLD classification which was proposed in 2007. We need a new childhood DPLD classification that will cover all these disease groups.