Heterogeneity of lung disease associated with NK2 homeobox 1 mutations

Systematic review of thyroid function in NKX2-1-related disorders: Screening and diagnosis

BACKGROUND

NKX2-1-related disorders (NKX2-1-RD) are rare conditions affecting lung, thyroid, and brain development, primarily caused by pathogenic variants or deletions in the NKX2-1 gene. Congenital hypothyroidism (CH) is a common endocrine manifestation, leading to irreversible intellectual disability if left untreated.

OBJECTIVES

The aim was to evaluate the current evidence for the use of screening and diagnostic techniques for endocrine alterations in patients with NKX2-1-RD.

METHODS

This systematic review was reported following the PRISMA guidelines. Two separate research questions in PICO format were addressed to cover initial screening and diagnosis procedures for endocrine diseases in patients with NKX2-1-RD. Eligibility criteria focused on patients with genetic confirmation of the disease and hypothyroidism. Various databases were searched, and data were extracted and assessed independently by two reviewers.

RESULTS

Out of 1012 potentially relevant studies, 46 were included, for a total of 113 patients. CH was the most frequent endocrine alteration (45% of patients). Neonatal screening was reported in only 21% of patients based on blood TSH measurements. TSH thresholds varied widely across studies, making hypothyroidism detection ranges difficult to establish. Diagnostic tests using serum TSH were used to diagnose hypothyroidism or confirm its presence. 35% of patients were diagnosed at neonatal age, and 42% at adult age. Other hormonal dysfunctions identified due to clinical signs, such as anterior pituitary deficiencies, were detected later in life. Thyroid scintigraphy and ultrasonography allowed for the description of the thyroid gland in 30% of cases of hypothyroidism. Phenotypic variability was observed in individuals with the same variants, making genotype-phenotype correlations challenging.

CONCLUSION

This review highlights the need for standardized protocols in endocrine screening for NKX2-1-RD, emphasizing the importance of consistent methodology and hormone threshold levels. Variability in NKX2-1 gene variants further complicates diagnostic efforts. Future research should concentrate on optimizing early screening protocols and diagnostic strategies.

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.

Insights from European Reference Network for rare neurological disorders study surveys on diagnosis, treatment, and management of NKX2-1-related disorders

BACKGROUND

NKX2-1-related disorder (NKX2-1-RD) is a rare disease characterized by a triad of primary hypothyroidism, neonatal respiratory distress, and neurological features, including chorea.

OBJECTIVE

This study aimed to identify discrepancies in the management of NKX2-1-RD among European Union (EU) specialists.

METHODS

The ERN-RND Chorea & Huntington disease group designed a survey to conduct a cross-sectional multicenter study on the management of NKX2-1-RD. Descriptive analysis was performed, and total responses are presented for each item.

RESULTS

The study involved 23 experts from 13 EU countries with experience in evaluating hyperkinetic patients with NKX2-1-RD: 11 were adult specialists, and 12 were pediatric specialists. NKX2-1-RD diagnosis was made at different ages, with the most common initial symptoms being hypotonia and/or motor developmental delay (reported by 11 experts) and chorea (reported by 8 experts). Chorea involved various body parts and showed improvement as reported by 9 experts, stabilization by 12 experts, and worsening by 2 experts with age. The pharmacological treatment of chorea varied widely among the experts. Misdiagnosis was reported by 14 experts. NKX2-1 pathogenic variants or deletions were confirmed in >75 % of patients (reported by 12 experts). Pulmonary and endocrinology evaluations were requested by 7 and 12 experts, respectively. The management of psychiatric comorbidities also varied among the different experts.

CONCLUSIONS

This study highlights the need for a clinical practice guideline for the management of NKX2-1-RD to ensure that patients across the EU receive consistent and appropriate care. Such a guideline would benefit both doctors and healthcare practitioners.

A Novel Missense Variant in the NKX2-1 Homeodomain Prevents Transcriptional Rescue by TAZ

Background: Brain-lung-thyroid syndrome (BLTS) is caused by NKX2-1 haploinsufficiency, resulting in chorea/choreoathetosis, respiratory problems, and hypothyroidism. Genes interacting with NKX2-1 mutants influence its phenotypic variability. We report a novel NKX2-1 missense variant and the modifier function of TAZ/WWTR1 in BLTS. Methods: A child with BLTS underwent next-generation sequencing panel testing for thyroid disorders. His family was genotyped for NKX2-1 variants and screened for germline mosaicism. Mutant NKX2-1 was generated, and transactivation assays were performed on three NKX2-1 target gene promoters. DNA binding capacity and protein-protein interaction were analyzed. Results: The patient had severe BLTS and carried a novel missense variant c.632A>G (p.N211S) in NKX2-1, which failed to bind to specific DNA promoters, reducing their transactivation. TAZ cotransfection did not significantly increase transcription of these genes, although the variant retained its ability to bind to TAZ. Conclusions: We identify a novel pathogenic NKX2-1 variant that causes severe BLTS and is inherited through germline mosaicism. The mutant lacks DNA-binding capacity, impairing transactivation and suggesting that NKX2-1 binding to DNA is essential for TAZ-mediated transcriptional rescue.

High risk of lung cancer in surfactant-related gene variant carriers

BACKGROUND

Several rare surfactant-related gene (SRG) variants associated with interstitial lung disease are suspected to be associated with lung cancer, but data are missing. We aimed to study the epidemiology and phenotype of lung cancer in an international cohort of SRG variant carriers.

METHODS

We conducted a cross-sectional study of all adults with SRG variants in the OrphaLung network and compared lung cancer risk with telomere-related gene (TRG) variant carriers.

RESULTS

We identified 99 SRG adult variant carriers (SFTPA1 (n=18), SFTPA2 (n=31), SFTPC (n=24), ABCA3 (n=14) and NKX2-1 (n=12)), including 20 (20.2%) with lung cancer (SFTPA1 (n=7), SFTPA2 (n=8), SFTPC (n=3), NKX2-1 (n=2) and ABCA3 (n=0)). Among SRG variant carriers, the odds of lung cancer was associated with age (OR 1.04, 95% CI 1.01-1.08), smoking (OR 20.7, 95% CI 6.60-76.2) and SFTPA1/SFTPA2 variants (OR 3.97, 95% CI 1.39-13.2). Adenocarcinoma was the only histological type reported, with programmed death ligand-1 expression ≥1% in tumour cells in three samples. Cancer staging was localised (I/II) in eight (40%) individuals, locally advanced (III) in two (10%) and metastatic (IV) in 10 (50%). We found no somatic variant eligible for targeted therapy. Seven cancers were surgically removed, 10 received systemic therapy, and three received the best supportive care according to their stage and performance status. The median overall survival was 24 months, with stage I/II cancers showing better survival. We identified 233 TRG variant carriers. The comparative risk (subdistribution hazard ratio) for lung cancer in SRG patients versus TRG patients was 18.1 (95% CI 7.1-44.7).

CONCLUSIONS

The high risk of lung cancer among SRG variant carriers suggests specific screening and diagnostic and therapeutic challenges. The benefit of regular computed tomography scan follow-up should be evaluated.

Functional characterization of two novel NKX2-1 frameshift variants that cause pulmonary surfactant dysfunction

BACKGROUND

We aim to report two unrelated patients with pulmonary surfactant dysfunction (PSD) that carried two novel NKX2-1 frameshift variants, and evaluated the impact of these variants in vitro.

METHODS

We enrolled children with PSD and NKX2-1 variants, and collected their clinical information and follow-up data. We constructed wild-type (WT) and variant NKX2-1 plasmids and transfected them into A549 and HEK293T cells. The functional characterization of variants was then evaluated by qRT-PCR, western blot, immunofluorescence, electrophoretic mobility shift assay, and dual-luciferase reporter assay.

RESULTS

Two novel heterozygous frameshift variants of NKX2-1, i.e., c.705delC (Gly236Alafs*29) and c.313_316 dup (Asn106Lysfs*304), were identified in children from two unrelated families. We discerned attenuated mRNA and protein expression in the Asn106Lysfs*304 variant, and reduced DNA -binding as well as transcriptional activation capabilities in both variants. While the Asn106Lysfs*304 variant lost its synergistic interactions with PAX8 and TAZ, the Gly236Alafs*29 variant partially retained its residual transcriptional activation capabilities and synergistic interactions with PAX8 and TAZ.

CONCLUSIONS

We reported on two children with two novel NKX2-1 frameshift variants. In vitro experiments revealed that the two frameshift variants have common and different mechanisms based on the loss or conservation of domains, which partially explained the phenotypical heterogeneity.

IMPACT

Pulmonary surfactant dysfunction is a rare heterogeneous disease that exhibits a great burden on children's quality of life. We reported two novel NKX2-1 frameshift variants carried by two children with different clinical phenotypes, thus broadening our knowledge base of gene variations and phenotypes in NKX2-1. We performed an in vitro study and uncovered different pathogenic mechanisms underlying the actions of two novel variants, and thereby partially explained the mechanisms of phenotypical heterogeneity caused by NKX2-1 variants.

Descriptive and Functional Genomics in Neonatal Respiratory Distress Syndrome: From Lung Development to Targeted Therapies

In this up-to-date study, we first aimed to highlight the genetic and non-genetic factors associated with respiratory distress syndrome (RDS) while also focusing on the genomic aspect of this condition. Secondly, we discuss the treatment options and the progressing therapies based on RNAs or gene therapy. To fulfill this, our study commences with lung organogenesis, a highly orchestrated procedure guided by an intricate network of conserved signaling pathways that ultimately oversee the processes of patterning, growth, and differentiation. Then, our review focuses on the molecular mechanisms contributing to both normal and abnormal lung growth and development and underscores the connections between genetic and non-genetic factors linked to neonatal RDS, with a particular emphasis on the genomic aspects of this condition and their implications for treatment choices and the advancing therapeutic approaches centered around RNAs or gene therapy.

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.

Systematic review of drug therapy for chorea in NXK2-1-related disorders: Efficacy and safety evidence from case studies and series

BACKGROUND

The NKX2-1-related disorders (NKX2-1-RD) is a rare disorder characterized by choreiform movements along with respiratory and endocrine abnormalities. The European Reference Network of Rare Neurological Disorders funded by the European Commission conducted a systematic review to assess drug treatment of chorea in NKX2-1-RD, aiming to provide clinical recommendations for its management.

METHODS

A systematic pairwise review using various databases, including MEDLINE, Embase, Cochrane, CINAHL, and PsycInfo, was conducted. The review included patients diagnosed with chorea and NKX2-1-RD genetic diagnosis, drug therapy as intervention, no comparator, and outcomes of chorea improvement and adverse events. The methodological quality of the studies was assessed, and the study protocol was registered in PROSPERO.

RESULTS

Of the 1417 studies examined, 28 studies met the selection criteria, consisting of 68 patients. The studies reported 22 different treatments for chorea, including carbidopa/levodopa, tetrabenazine, clonazepam, methylphenidate, carbamazepine, topiramate, trihexyphenidyl, haloperidol, propranolol, risperidone, and valproate. No clinical improvements were observed with carbidopa/levodopa, tetrabenazine, or clonazepam, and various adverse effects were reported. However, most patients treated with methylphenidate experienced improvements in chorea and reported only a few negative effects. The quality of evidence was determined to be low.

CONCLUSIONS

The management of chorea in individuals with NKX2-1-RD presents significant heterogeneity and lack of clarity. While the available evidence suggests that methylphenidate may be effective in improving chorea symptoms, the findings should be interpreted with caution due to the limitations of the studies reviewed. Nonetheless, more rigorous and comprehensive studies are necessary to provide sufficient evidence for clinical recommendations.

Lung transplantation outcome in adult surfactant-related interstitial lung disease: first evidence to move on

A new study reports the first evidence to "move on" with lung transplantation in adult surfactant-related fibrotic ILDs. It highlights the need for better genetic characterisation of transplant candidates and cancer screening for these patients. https://bit.ly/3QxG73Z.

Molecular and Genetic Biomarkers in Idiopathic Pulmonary Fibrosis: Where Are We Now?

Idiopathic pulmonary fibrosis (IPF) represents a chronic progressive fibrotic interstitial lung disease of unknown cause with an ominous prognosis. It remains an unprecedent clinical challenge due to its delayed diagnosis and unpredictable clinical course. The need for accurate diagnostic, prognostic and predisposition biomarkers in everyday clinical practice becomes more necessary than ever to ensure prompt diagnoses and early treatment. The identification of such blood biomarkers may also unravel novel drug targets against IPF development and progression. So far, the role of diverse blood biomarkers, implicated in various pathogenetic pathways, such as in fibrogenesis (S100A4), extracellular matrix remodelling (YKL-40, MMP-7, ICAM-1, LOXL2, periostin), chemotaxis (CCL-18, IL-8), epithelial cell injury (KL-6, SP-A, SP-D), autophagy and unfolded protein response has been investigated in IPF with various results. Moreover, the recent progress in genetics in IPF allows for a better understanding of the underlying disease mechanisms. So far, the causative mutations in pulmonary fibrosis include mutations in telomere-related genes and in surfactant-related genes, markers that could act as predisposition biomarkers in IPF. The aim of this review is to provide a comprehensive overview from the bench to bedside of current knowledge and recent insights on biomarkers in IPF, and to suggest future directions for research. Large-scale studies are still needed to confirm the exact role of these biomarkers.

Genetic and environmental factors in interstitial lung diseases: current and future perspectives on early diagnosis of high-risk cohorts

Within the wide scope of interstitial lung diseases (ILDs), familial pulmonary fibrosis (FPF) is being increasingly recognized as a specific entity, with earlier onset, faster progression, and suboptimal responses to immunosuppression. FPF is linked to heritable pathogenic variants in telomere-related genes (TRGs), surfactant-related genes (SRGs), telomere shortening (TS), and early cellular senescence. Telomere abnormalities have also been identified in some sporadic cases of fibrotic ILD. Air pollution and other environmental exposures carry additive risk to genetic predisposition in pulmonary fibrosis. We provide a perspective on how these features impact on screening strategies for relatives of FPF patients, interstitial lung abnormalities, ILD multi-disciplinary team (MDT) discussion, and disparities and barriers to genomic testing. We also describe our experience with establishing a familial interstitial pneumonia (FIP) clinic and provide guidance on how to identify patients with telomere dysfunction who would benefit most from genomic testing.

NKX2.1 mutation revealed by a lymphoid interstitial pneumonia in an adult with rheumatoid arthritis

This is the first case of a 37-year-old female patient carrier of a heterozygous NKX2.1 mutation associated with RA-ILD with a histological pattern of LIP. This case illustrates the wide panel of ILD subtypes associated with NKX2.1 mutations. https://bit.ly/3F49OTS.

Unlocking the potential of induced pluripotent stem cells for neonatal disease modeling and drug development

Neonatal lung and heart diseases, albeit rare, can result in poor quality of life, often require long-term management and/or organ transplantation. For example, Congenital Heart Disease (CHD) is one of the most common type of congenital disabilities, affecting nearly 1% of the newborns, and has complex and multifactorial causes, including genetic predisposition and environmental influences. To develop new strategies for heart and lung regeneration in CHD and neonatal lung disease, human induced pluripotent stem cells (hiPSCs) provide a unique and personalized platform for future cell replacement therapy and high-throughput drug screening. Additionally, given the differentiation potential of iPSCs, cardiac cell types such as cardiomyocytes, endothelial cells, and fibroblasts and lung cell types such Type II alveolar epithelial cells can be derived in a dish to study the fundamental pathology during disease progression. In this review, we discuss the applications of hiPSCs in understanding the molecular mechanisms and cellular phenotypes of CHD (e.g., structural heart defect, congenital valve disease, and congenital channelopathies) and congenital lung diseases, such as surfactant deficiencies and Brain-Lung-Thyroid syndrome. We also provide future directions for generating mature cell types from iPSCs, and more complex hiPSC-based systems using three-dimensional (3D) organoids and tissue-engineering. With these potential advancements, the promise that hiPSCs will deliver new CHD and neonatal lung disease treatments may soon be fulfilled.

European Respiratory Society statement on familial pulmonary fibrosis

Genetic predisposition to pulmonary fibrosis has been confirmed by the discovery of several gene mutations that cause pulmonary fibrosis. Although genetic sequencing of familial pulmonary fibrosis (FPF) cases is embedded in routine clinical practice in several countries, many centres have yet to incorporate genetic sequencing within interstitial lung disease (ILD) services and proper international consensus has not yet been established. An international and multidisciplinary expert Task Force (pulmonologists, geneticists, paediatrician, pathologist, genetic counsellor, patient representative and librarian) reviewed the literature between 1945 and 2022, and reached consensus for all of the following questions: 1) Which patients may benefit from genetic sequencing and clinical counselling? 2) What is known of the natural history of FPF? 3) Which genes are usually tested? 4) What is the evidence for telomere length measurement? 5) What is the role of common genetic variants (polymorphisms) in the diagnostic workup? 6) What are the optimal treatment options for FPF? 7) Which family members are eligible for genetic sequencing? 8) Which clinical screening and follow-up parameters may be considered in family members? Through a robust review of the literature, the Task Force offers a statement on genetic sequencing, clinical management and screening of patients with FPF and their relatives. This proposal may serve as a basis for a prospective evaluation and future international recommendations.

Exploring the values, preferences, and information needs of patients with NKX2-1-related disorders: A qualitative study protocol

BACKGROUND

NKX2-1-related disorders have a prevalence of 1:500,000 and are therefore considered a rare condition according to the European Commission's definition. The European Reference Network of Rare Neurological Disorders is developing the first clinical practice guideline on the management of this condition, with the support of the Andalusian Health Technology Assessment Area, Endo-ERN, ERN-Lung and Imegen, within the framework of the ERNs Guidelines programme (DG SANTE/2018/B3/030). Within the scope of this programme, it becomes necessary to explore the patient perspective in order to include it in the ongoing clinical practice guideline and accompanying patient information booklet.

METHODS AND ANALYSIS

This study will use qualitative methods to explore the values, preferences and information needs of patient with NKX2-1-related disorders and their caregivers. Participants will come from a variety of countries throughout Europe. One focus group and four semi-structured interviews will be conducted. Pairs will analyse the data using Grounded Theory. The Andalusian Regional Ministry of Health's Ethics Coordinating Committee for Biomedical Research (Sevilla, Andalucía, Spain) has approved this study protocol (29/03/2022).

DISCUSSION

This is the first study to explore the values, preferences, and information needs of patients with NKX2-1-related disorders. The proposed study's findings will contribute to the generation of useful knowledge that will provide guidance to improve the care given to patients with the studied condition. While this study will provide valuable insights into the perspectives of patients with NKX2-1-related disorders, the findings are unlikely to be generalizable to patients with other conditions.

[Interstitial lung diseases in children of genetic origin]

Interstitial lung diseases in children of genetic origin. Interstitial lung disease (ILD) in children (chILD) encompasses a heterogeneous group of rare respiratory disorders, most of which are chronic and severe. In more and more of these cases, a genetic cause has been identified. As of now, the main mutations have been localized in the genes encoding the surfactant proteins (SP)-C (SFTPC), SP-B (SFTPB), their transporter ATP-binding cassette, family 1, member 3 (ABCA3), transcription factor NK2 homeobox 1 (NKX2-1) and, more rarely, SP-A1 (SFTPA1) or SP-A2 (SFTPA2). Pediatric pulmonary alveolar proteinosis (PAP) is associated with mutations in CSF2RA, CSF2RB, and MARS; more recently, mutations in STING1 and COPA have been associated with specific auto-inflammatory disorders including ILD manifestations. The relationships between the molecular abnormalities and the phenotypic expressions generally remain poorly understood. In the coming years, it is expected that newly identified molecular defects will help to more accurately predict disease courses and to produce individualized targeted therapies.

Genetics in Idiopathic Pulmonary Fibrosis: A Clinical Perspective

BACKGROUND

Unraveling the genetic background in a significant proportion of patients with both sporadic and familial IPF provided new insights into the pathogenic pathways of pulmonary fibrosis.

AIM

The aim of the present study is to overview the clinical significance of genetics in IPF.

PERSPECTIVE

It is fascinating to realize the so-far underestimated but dynamically increasing impact that genetics has on aspects related to the pathophysiology, accurate and early diagnosis, and treatment and prevention of this devastating disease. Genetics in IPF have contributed as no other in unchaining the disease from the dogma of a "a sporadic entity of the elderly, limited to the lungs" and allowed all scientists, but mostly clinicians, all over the world to consider its many aspects and "faces" in all age groups, including its co-existence with several extra pulmonary conditions from cutaneous albinism to bone-marrow and liver failure.

CONCLUSION

By providing additional evidence for unsuspected characteristics such as immunodeficiency, impaired mucus, and surfactant and telomere maintenance that very often co-exist through the interaction of common and rare genetic variants in the same patient, genetics have created a generous and pluralistic yet unifying platform that could lead to the understanding of the injurious and pro-fibrotic effects of many seemingly unrelated extrinsic and intrinsic offending factors. The same platform constantly instructs us about our limitations as well as about the heritability, the knowledge and the wisdom that is still missing.

Deciphering an isolated lung phenotype of NKX2-1 frameshift pathogenic variant

BACKGROUND

to perform a functional analysis of a new NK2 homeobox 1 (NKX2-1) variant (c.85_86del denominated NKX2-1^DEL) identified in a family presenting with isolated respiratory disease, in comparison to another frameshift variant (c.254dup denominated NKX2-1^DUP) identified in a subject with classical brain-lung-thyroid syndrome.

METHODS

pathogenic variants were introduced into the pcDNA3-1(+)-wt-TTF1 plasmid. The proteins obtained were analyzed by western blot assay. Subcellular localization was assessed by confocal microscopy in A549 and Nthy cells. Transactivation of SFTPA, SFTPB, SFTPC, and ABCA3 promoters was assessed in A549 cells. Thyroglobulin promoter activity was measured with the paired box gene 8 (PAX8) cofactor in Nthy cells.

RESULTS

The two sequence variants were predicted to produce aberrant proteins identical from the 86th amino acid, with deletion of their functional homeodomain, including the nuclear localization signal. However, 3D conformation prediction of the conformation prediction of the mutant protein assumed the presence of a nuclear localization signal, a bipartite sequence, confirmed by confocal microscopy showing both mutant proteins localized in the nucleus and cytoplasm. Transcriptional activity with SFTPA, SFTPB, SFTPC, ABCA3 and thyroglobulin promoters was significantly decreased with both variants. However, with NKX2-1^DEL, thyroglobulin transcriptional activity was maintained with the addition of PAX8.

CONCLUSION

These results provide novel insights into understanding the molecular mechanism of phenotypes associated with NKX2-1 pathogenic variants.

Comprehensive epigenomic profiling of human alveolar epithelial differentiation identifies key epigenetic states and transcription factor co-regulatory networks for maintenance of distal lung identity

BACKGROUND

Disruption of alveolar epithelial cell (AEC) differentiation is implicated in distal lung diseases such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and lung adenocarcinoma that impact morbidity and mortality worldwide. Elucidating underlying disease pathogenesis requires a mechanistic molecular understanding of AEC differentiation. Previous studies have focused on changes of individual transcription factors, and to date no study has comprehensively characterized the dynamic, global epigenomic alterations that facilitate this critical differentiation process in humans.

RESULTS

We comprehensively profiled the epigenomic states of human AECs during type 2 to type 1-like cell differentiation, including the methylome and chromatin functional domains, and integrated this with transcriptome-wide RNA expression data. Enhancer regions were drastically altered during AEC differentiation. Transcription factor binding analysis within enhancer regions revealed diverse interactive networks with enrichment for many transcription factors, including NKX2-1 and FOXA family members, as well as transcription factors with less well characterized roles in AEC differentiation, such as members of the MEF2, TEAD, and AP1 families. Additionally, associations among transcription factors changed during differentiation, implicating a complex network of heterotrimeric complex switching in driving differentiation. Integration of AEC enhancer states with the catalog of enhancer elements in the Roadmap Epigenomics Mapping Consortium and Encyclopedia of DNA Elements (ENCODE) revealed that AECs have similar epigenomic structures to other profiled epithelial cell types, including human mammary epithelial cells (HMECs), with NKX2-1 serving as a distinguishing feature of distal lung differentiation.

CONCLUSIONS

Enhancer regions are hotspots of epigenomic alteration that regulate AEC differentiation. Furthermore, the differentiation process is regulated by dynamic networks of transcription factors acting in concert, rather than individually. These findings provide a roadmap for understanding the relationship between disruption of the epigenetic state during AEC differentiation and development of lung diseases that may be therapeutically amenable.

NKX2.1 (TTF1) germline mutation associated with pulmonary fibrosis and lung cancer

The high prevalence of lung cancer in patients with idiopathic pulmonary fibrosis (3–30%) has been confirmed by several studies, pointing to specific diagnostic and therapeutic issues. The co-occurrence is associated with worse survival than with each disease alone [1]. Because cigarette smoking is a risk factor for both diseases, smoking is an ideal culprit for their co-occurrence, despite several common pathogenic mechanisms such as common genetic risk factors.

Germline surfactant-associated genes mutations are associated with ILD and increased risk of lung cancerhttps://bit.ly/3CkkXgD

Strategies for the Neonatal Lung Biopsy: Histology to Genetics

Neonatal lung biopsy guides important medical decisions when the diagnosis is not clear from prior clinical assessment, imaging, or genetic testing. Common scenarios that lead to biopsy include severe acute respiratory distress in a term neonate, pulmonary hypertension disproportionate to that expected for gestational age or known cardiac anomalies, and assessment of suspected genetic disorder based on clinical features or genetic variant of unknown significance. The differential diagnosis includes genetic developmental disorders, genetic surfactant disorders, vascular disorders, acquired infection, and meconium aspiration. This article describes pathologic patterns in the neonatal lung and correlation with molecular abnormalities, where appropriate.

Brain-lung-thyroid syndrome in a neonate with argininosuccinate lyase deficiency

Argininosuccinate lyase (ASL) deficiency is a rare autosomal recessive urea cycle disorder. The severe neonatal-onset form is characterised by hyperammonaemia in the first days of life and manifests with a variety of severe symptoms. However, an index of suspicion for additional or alternative diagnoses must be maintained when the patient's presentation is out of keeping with expected manifestations and course. We present a case of a neonate with ASL deficiency and concomitant hypotonia, severe respiratory distress, pulmonary hypertension, systemic hypotension and congenital hypothyroidism. The patient was investigated and subsequently diagnosed with brain-lung-thyroid syndrome, caused by a mutation in the NKX2-1 gene.

Genetic disorders of the surfactant system: focus on adult disease

Genes involved in the production of pulmonary surfactant are crucial for the development and maintenance of healthy lungs. Germline mutations in surfactant-related genes cause a spectrum of severe monogenic pulmonary diseases in patients of all ages. The majority of affected patients present at a very young age, however, a considerable portion of patients have adult-onset disease. Mutations in surfactant-related genes are present in up to 8% of adult patients with familial interstitial lung disease (ILD) and associate with the development of pulmonary fibrosis and lung cancer.High disease penetrance and variable expressivity underscore the potential value of genetic analysis for diagnostic purposes. However, scarce genotype-phenotype correlations and insufficient knowledge of mutation-specific pathogenic processes hamper the development of mutation-specific treatment options.This article describes the genetic origin of surfactant-related lung disease and presents spectra for gene, age, sex and pulmonary phenotype of adult carriers of germline mutations in surfactant-related genes.

Hypoxaemia and interstitial lung disease in an infant with hypothyroidism and hypotonia

A 7-month-old-term male infant presented with cough, tachypnoea, hypoxaemia and post-tussive emesis. Clinical history was significant for respiratory failure and pulmonary hypertension in the neonatal period requiring assisted ventilation, congenital hypothyroidism, mild hypotonia, recurrent respiratory infections, hypoxaemia requiring supplemental oxygen and nasogastric tube feeds. Physical examination showed tachypnoea, coarse bilateral breath sounds and mild hypotonia. Chest radiograph revealed multifocal pulmonary opacities with coarse interstitial markings and right upper lobe atelectasis. Following antibiotic therapy for suspected aspiration pneumonia, chest CT scan was performed and showed multiple areas of pulmonary consolidation and scattered areas of bilateral ground-glass opacities. Genetic studies showed a large deletion of chromosome 14q13.1-14q21.1, encompassing the NK2 homeobox 1 (NKX2-1) gene consistent with a diagnosis of brain-thyroid-lung (BTL) syndrome. Our case highlights the importance of genetic studies to diagnose BTL syndrome in infants with hypothyroidism, hypotonia and lung disease.

Interstitial lung disease in infancy

There is a wide differential diagnosis of early onset respiratory distress especially in term babies, and interstitial lung disease (chILD) is a rare but important consideration in this context. chILD manifesting immediately after birth is usually related to mutations in surfactant protein genes, or conditions related to the Congenital Acinar Dysplasia -Alveolar capillary dysplasia - Congenital Alveolar Dysplasia (CAD-ACD) spectrum. There is currently no specific treatment for these conditions, and management is supportive. Prognosis is very poor in most of these babies if onset is early, with relentless respiratory deterioration unless transplanted. Ideally, the diagnosis is made on genetic analysis, but this may be time-consuming and complex in CAD-ACD spectrum, so lung biopsy may be needed to avoid prolonged and futile treatment being instituted. Milder forms with prolonged survival have been reported. Early onset, less severe chILD is usually related to neuroendocrine cell hyperplasia of infancy (NEHI), pulmonary interstitial glycogenosis (PIG) and less severe disorders of surfactant proteins. PIG and NEHI are not specific entities, but are pulmonary dysmaturity syndromes, and there may be a number of underlying genetic and other cause. If the child is stable and thriving, many will not be subject to lung biopsy, and slow improvement and weaning of supplemental oxygen can be anticipated. Where possible, a precise genetic diagnosis should be made in early onset cHILD allow for genetic counselling. chILD survivors and their families have complex respiratory and other needs, and co-ordinated, multi-disciplinary support in the community is essential.

Interstitial Lung Disease in Rare Congenital Syndromes

Diffuse or interstitial lung disease (DLD/ILD) comprises a diverse group of disorders that involve the pulmonary parenchyma. Its aetiology varies (which makes the diagnostic process difficult), but congenital diseases, including malformation syndromes or developmental disorders, constitute one of the causative factors. They are rare conditions, and thus their frequency is not high. However, considering the progress and increasing availability of genetic testing, detection of these rare syndromes may increase. The aim of this work is, therefore, to present the symptomatology of selected congenital syndromes with ILD, taking into account the genetic background.

The future is here: Integrating genetics into the pediatric pulmonary clinic

Recognition of underlying genetic etiologies of disease is increasing at an exponential rate, likely due to greater access to and lower cost of genetic testing. Monogenic causes of disease, or conditions resulting from a mutation or mutations in a single gene, are now well recognized in every subspecialty, including pediatric pulmonary medicine; thus, it is important to consider genetic conditions when evaluating children with respiratory disease. In the pediatric pulmonary clinic, genetic testing should be considered when multiple family members present with similar or related clinical features and when individuals have unusual clinical presentations, such as early-onset disease or complex, syndromic features. This review provides a practical guide for genetic diagnosis in the pediatric pulmonary setting, including a review of genetic concepts, considerations for test selection and results in interpretation, as well as an overview of genetic differential diagnoses for common pediatric pulmonary phenotypes. Genetic conditions that commonly present to the pediatric pulmonary clinic are reviewed in a companion article by Yonker et al.

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.

Pulmonary alveolarproteinosis in children

Pulmonary alveolar proteinosis (PAP) is an umbrella term for a wide spectrum of conditions that have a very characteristic appearance on computed tomography. There is outlining of the secondary pulmonary lobules on the background of ground-glass shadowing and pathologically, filling of the alveolar spaces with normal or abnormal surfactant. PAP is rare and the common causes in children are very different from those seen in adults; autoimmune PAP is rare and macrophage blockade not described in children. There are many genetic causes of PAP, the best known of which are mutations in the genes encoding surfactant protein (SP)-B, SP-C, thyroid transcription factor 1, ATP-binding cassette protein 3, and the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor α- and β- chains. PAP may also be a manifestation of rheumatological and metabolic disease, congenital immunodeficiency, and haematological malignancy. Precise diagnosis of the underlying cause is essential in planning treatment, as well as for genetic counselling. The evidence base for treatment is poor. Some forms of PAP respond well to whole-lung lavage, and autoimmune PAP, which is much commoner in adults, responds to inhaled or subcutaneous GM-CSF. Emerging therapies based on studies in murine models of PAP include stem-cell transplantation for GM-CSF receptor mutations.

EDUCATIONAL AIMS

To understand when to suspect that a child has pulmonary alveolar proteinosis (PAP) and how to confirm that this is the cause of the presentation.To show that PAP is an umbrella term for conditions characterised by alveolar filling by normal or abnormal surfactant, and that this term is the start, not the end, of the diagnostic journey.To review the developmental differences in the spectrum of conditions that may cause PAP, and specifically to understand the differences between causes in adults and children.To discuss when to treat PAP with whole-lung lavage and/or granulocyte-macrophage colony-stimulating factor, and review potential promising new therapies.

Lung ultrasound-a new diagnostic modality in persistent tachypnea of infancy

Lung ultrasound (LUS) has been increasingly used in diagnosing and monitoring of various pulmonary diseases in children. The aim of the current study was to evaluate its usefulness in children with persistent tachypnea of infancy (PTI). This was a controlled, prospective, cross-sectional study that included children with PTI and healthy subjects. In patients with PTI, LUS was performed at baseline and then after 6 and 12 months of follow-up. Baseline results of LUS were compared to (a) baseline high-resolution computed tomography (HRCT) images, (b) LUS examinations in control group, and (c) follow-up LUS examinations. Twenty children with PTI were enrolled. B-lines were found in all children with PTI and in 11 (55%) control subjects (P < .001). The total number of B-lines, the maximal number of B lines in any intercostal space, the distance between B-lines, and pleural thickness were significantly increased in children with PTI compared to controls. An irregularity of the pleural line was found in all patients with PTI and in none of the healthy children. There were no significant changes in LUS findings in patients with PTI during the study period. The comparison of HRCT indices and LUS findings revealed significant correlations between the mean lung attenuation, skewness, kurtosis and fraction of interstitial pulmonary involvement, and the number of B-lines as well as the pleural line thickness. LUS seems to be a promising diagnostic tool in children with PTI. Its inclusion in the diagnostic work-up may enable to reduce the number of costly, hazardous, and ionizing radiation-based imaging procedures.

Azithromycin is the answer in paediatric respiratory medicine, but what was the question?

The first clinical indication of non-antibiotic benefits of macrolides was in the Far East, in adults with diffuse panbronchiolitis. This condition is characterised by chronic airway infection, often with Pseudomonas aeruginosa, airway inflammation, bronchiectasis and a high mortality. Low dose erythromycin, and subsequently other macrolides, led in many cases to complete remission of the condition, and abrogated the neutrophilic airway inflammation characteristic of the disease. This dramatic finding sparked a flurry of interest in the many hundreds of macrolides in nature, especially their anti-inflammatory and immunomodulatory effects. The biggest subsequent trials of azithromycin were in cystic fibrosis, which has obvious similarities to diffuse panbronchiolitis. There were unquestionable improvements in lung function and pulmonary exacerbations, but compared to diffuse panbronchiolitis, the results were disappointing. Case reports, case series and some randomised controlled trials followed in other conditions. Three trials of azithromycin in preschool wheeze gave contradictory results; a trial in pauci-inflammatory adult asthma, and a trial in non-cystic fibrosis bronchiectasis both showed a significant reduction in exacerbations, but none matched the dramatic results in diffuse panbronchiolitis. There is clearly a huge risk of antibacterial resistance if macrolides are used widely and uncritically in the community. In summary, Azithromycin is not the answer to anything in paediatric respiratory medicine; the paediatric respiratory community needs to refocus on the dramatic benefits of macrolides in diffuse panbronchiolitis, use modern - omics technologies to determine the endotypes of inflammatory diseases and discover in nature or synthesise designer macrolides to replicate the diffuse panbronchiolitis results. We must now find out how to do better!

Familial Interstitial Lung Disease

The interstitial lung diseases (ILDs) are a group of progressive disorders characterized by chronic inflammation and/or fibrosis in the lung. While some ILDs can be linked to specific environmental causes (i.e., asbestosis, silicosis), in many individuals, no culprit exposure can be identified; these patients are deemed to have "idiopathic interstitial pneumonia" (IIP). Family history is now recognized as the strongest risk factor for IIP, and IIP cases that run in families comprise a syndrome termed "familial interstitial pneumonia" (FIP). Mutations in more than 10 different genes have been implicated as responsible for disease in FIP families. Diverse ILD clinical phenotypes can be seen within a family, and available evidence suggests underlying genetic risk is the primary determinant of disease outcomes. Together, these FIP studies have provided unique insights into the pathobiology of ILDs, and brought focus on the unique issues that arise in the care of patients with FIP.

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.

Pilot experience of multidisciplinary team discussion dedicated to inherited pulmonary fibrosis

Background

Genetic testing is proposed for suspected cases of monogenic pulmonary fibrosis, but clinicians and patients need specific information and recommendation about the related diagnosis and management issues. Because multidisciplinary discussion (MDD) has been shown to improve accuracy of interstitial lung disease (ILD) diagnosis, we evaluated the feasibility of a genetic MDD (geneMDD) dedicated to the indication for and interpretation of genetic testing. The geneMDD group met monthly and included pediatric and adult lung specialists with ILD expertise, molecular and clinical geneticists, and one radiologist. Hematologists, rheumatologists, dermatologists, hepatologists, and pathologists were also invited to attend.

Results

Since 2016, physicians from 34 different centers in 7 countries have participated in the geneMDD. The medical files of 95 patients (53 males) have been discussed. The median age of patients was 43 years [range 0–77], 10 were ≤ 15 years old, and 6 were deceased at the time of the discussion. Among 85 analyses available, the geneMDD considered the rare gene variants pathogenic for 61: 37 variants in telomere-related genes, 23 variants in surfactant-related genes and 1 variant in MARS. Genetic counseling was offered for relatives of these patients. The geneMDD therapeutic proposals were as follows: antifibrotic drugs (n = 25), steroids or immunomodulatory therapy (n = 18), organ transplantation (n = 21), watch and wait (n = 21), or best supportive care (n = 4).

Conclusion

Our experience shows that a dedicated geneMDD is feasible regardless of a patient’s age and provides a unique opportunity to adapt patient management and therapy in this very rare condition.

The genetics of interstitial lung diseases

Interstitial lung diseases (ILDs) are a set of heterogeneous lung diseases characterised by inflammation and, in some cases, fibrosis. These lung conditions lead to dyspnoea, cough, abnormalities in gas exchange, restrictive physiology (characterised by decreased lung volumes), hypoxaemia and, if progressive, respiratory failure. In some cases, ILDs can be caused by systemic diseases or environmental exposures. The ability to treat or cure these ILDs varies based on the subtype and in many cases lung transplantation remains the only curative therapy. There is a growing body of evidence that both common and rare genetic variants contribute to the development and clinical manifestation of many of the ILDs. Here, we review the current understanding of genetic risk and ILD.

Common and rare genetic variants contribute to the development and clinical manifestation of many interstitial lung diseaseshttp://bit.ly/31loHLh

Pulmonary Fibrosis in Children

: Pulmonary fibrosis (PF) is a very rare condition in children, which may be observed in specific forms of interstitial lung disease. None of the clinical, radiological, or histological descriptions used for PF diagnosis in adult patients, especially in situations of idiopathic PF, can apply to pediatric situations. This observation supports the view that PF expression may differ with age and, most likely, may cover distinct entities. The present review aims at summarizing the current understanding of PF pathophysiology in children and identifying suitable diagnostic criteria.

Genetic basis of surfactant dysfunction in Chinese children: A retrospective study

OBJECTIVE

To investigate the prevalence of surfactant dysfunction (SD) and the genotype distribution in Chinese childhood interstitial lung disease (chILD).

METHODS

From December 2013 to December 2016, whole exons and splicing regions of surfactant protein (SP)-B, SP-C, and adenosine triphosphate (ATP)-binding cassette subfamily A member 3 (ABCA3) were sequenced in chILD with unknown etiology in five children's medical centers of China. The sequencing was performed by Next-generation sequencing technique in a molecular genetics laboratory. The clinical and genetic data were reviewed retrospectively.

RESULTS

In total, 136 patients of age 3 months to 13 years (mean 12.5 ± 9.4 months) were recruited, among which 76 were males. Of the 136 cases of chILD, 13.2% (18 of 136) were diagnosed with SD. In these 18 SD cases, 15 had heterozygous SP-C deficiencies, two cases had compound heterozygous ABCA3 deficiencies, and no SP-B deficiency was identified. In SP-C deficiencies, there were six cases with p.I73T, 2 with p.I73N, 5 with p.V39L, 1 with c.417delA, and 1 case with IVS4, +1G>C. Two cases of ABCA3 mutation were heterozygous with c.1755delC and c.2890G>A; c.3913T>C (R1305W) and exon 13 to 18 deletion. One was negative by sequencing while diagnosed positive by pathology.

CONCLUSION

The proportion of genetic mutation of SD in chILD is 13.2% in China, of which SP-C deficiency is predominant. The mutation, SP-C p.V39L, was found to be relatively prevalent in China and warrants further investigation.

High-resolution computed tomography findings of thyroid transcription factor 1 deficiency (NKX2-1 mutations)

BACKGROUND

The expression of the NKX2-1 gene and its encoded protein, thyroid transcription factor 1 (TTF-1), plays a role in pulmonary surfactant homeostasis and lung development. NKX2-1 mutations have been associated with neonatal respiratory distress, hypotonia, choreoathetosis and congenital hypothyroidism. These clinical findings have been coined brain-lung-thyroid syndrome, although not all three organs are always involved. While many of these children develop interstitial lung disease, no systematic review of chest high-resolution CT (HRCT) findings has been reported.

OBJECTIVE

To summarize the clinical presentations, pathology and HRCT imaging findings of children with NKX2-1 mutations.

MATERIALS AND METHODS

We identified six children with NKX2-1 mutations, deletions or duplications confirmed via genetic testing at our institution. Three pediatric radiologists reviewed the children's HRCT imaging findings and ranked the dominant findings in order of prevalence via consensus. We then correlated the imaging findings with histopathology and clinical course.

RESULTS

All children in the study were heterozygous for NKX2-1 mutations, deletions or duplications. Ground-glass opacities were the most common imaging feature, present in all but one child. Consolidation was also a prevalent finding in 4/6 of the children. Architectural distortion was less common.

CONCLUSION

HRCT findings of TTF-1 deficiency are heterogeneous and evolve over time. There is significant overlap between the HRCT findings of TTF-1 deficiency, other surfactant dysfunction mutations, and pulmonary interstitial glycogenosis. TTF-1 deficiency should be considered in term infants presenting with interstitial lung disease, especially if hypotonia or hypothyroidism is present.

Building and Regenerating the Lung Cell by Cell

The unique architecture of the mammalian lung is required for adaptation to air breathing at birth and thereafter. Understanding the cellular and molecular mechanisms controlling its morphogenesis provides the framework for understanding the pathogenesis of acute and chronic lung diseases. Recent single-cell RNA sequencing data and high-resolution imaging identify the remarkable heterogeneity of pulmonary cell types and provides cell selective gene expression underlying lung development. We will address fundamental issues related to the diversity of pulmonary cells, to the formation and function of the mammalian lung, and will review recent advances regarding the cellular and molecular pathways involved in lung organogenesis. What cells form the lung in the early embryo? How are cell proliferation, migration, and differentiation regulated during lung morphogenesis? How do cells interact during lung formation and repair? How do signaling and transcriptional programs determine cell-cell interactions necessary for lung morphogenesis and function?

Chronic interstitial lung diseases in children: diagnosis approaches

Introduction: Children interstitial lung disease (chILD) is a heterogeneous group of rare respiratory disorders characterized by inflammatory and fibrotic changes of the lung parenchyma. They include ILD related to exposure/environment insults, ILD related to systemic diseases processes, ILD related to primary lung parenchyma dysfunctions and ILD specific to infancy. Areas covered: This review provides an update on chILD pathophysiology and diagnosis approaches in immunocompetent children. It includes current information on genetic causes. Expert commentary: ChILD covers a large spectrum of entities with heterogeneous disease expression. Various classifications have been reported, but none of them seems completely satisfactory. Recently, progress in molecular genetics has allowed identifying some genetic contributors, with, so far, a lack of correlations between gene disorders and disease expression. Despite improvements in patient management, chILD prognosis is still burdened by significant morbidity and mortality. Ongoing international collaborations will allow gathering larger longitudinal cohorts of patients to improve disease knowledge and personalized care. The overall goal is to help the children with ILD to reach the adulthood transition in a better condition, and to structure genetic counseling for their family.

Side effects of medications used to treat childhood interstitial lung disease

Interstitial lung disease in children (chILD) comprises a range of different rare diseases. There is limited evidence for the treatment of chILD and no randomised clinical trials of treatment have been undertaken. Most treatments are therefore prescribed off-label based on expert opinion. The off-label nature of prescription of drugs for chILD highlights the importance of a solid understanding of the side effects to facilitate risk-benefit assessment. The European Respiratory Society chILD guidelines recommend the use of systemic glucocorticosteroids, hydroxychloroquine and azithromycin. Side effects of these drugs will be discussed followed by consideration of other drugs used for the treatment of chILD.

An update on paediatric respiratory diseases

During the 2017 European Respiratory Society International Congress in Milan, Italy, exciting topics on childhood lung disease were reviewed in the session “Paediatric year in review: update on paediatric pulmonology”. These brief reviews highlighted publications in the field of paediatric lung disease and were presented by well-known experts within the field.

An update of paediatric lung diseases including interstitial lung disease, virus causing wheezing disorders and diaphragmatic hernia together with new imaging diagnosis toolshttp://ow.ly/TclX30iZazK