For newborns suspected having childhood interstitial lung disease (ChILD), the sequencing of genes encoding surfactant proteins is recommended. However, it is still difficult to interpret the clinical significance of those variants found. We report a full-term born female infant who presented with respiratory distress and failure to thrive at 2 months of age and both imaging and lung biopsy were consistent with ChILD. Her genetic test was initially reported as a variant of unknown significance in surfactant protein C (c.202G > T, p.V68F), which was modified later as likely pathogenic after reviewing a report of the same variant as causing ChILD. The infant was placed on noninvasive ventilation and treated with IV Methylprednisolone, Hydroxychloroquine, and Azithromycin but did not show significant clinical and radiological improvement underwent tracheostomy and is awaiting lung transplantation at 8 months of age. The challenges interpreting the genetic results are discussed.

Pulmonary surfactant is a complex mixture of lipids and specific proteins that stabilizes alveoli at the end of expiration and has an important role in innate immune defense. Genetic or autoimmune mechanisms that disrupt the normal production, function, or catabolism of surfactant can result in diffuse lung disease that is variable in its onset, ranging from the newborn period to adulthood, as well as severity. While rare, these disorders are associated with significant morbidity and mortality and provide insights into normal lung cell metabolism. This chapter will review the epidemiology, pathophysiology, and clinical and laboratory aspects of these disorders and discuss the approach to diagnosis and treatment.

A novel multi-organ disease that is fatal in early childhood was identified in three patients from two non-consanguineous families. These children were born asymptomatic but at the age of 2 months they manifested progressive multi-organ symptoms resembling no previously known disease. The main clinical features included progressive cerebropulmonary symptoms, malabsorption, progressive growth failure, recurrent infections, chronic haemolytic anaemia and transient liver dysfunction. In the affected children, neuropathology revealed increased angiomatosis-like leptomeningeal, cortical and superficial white matter vascularisation and congestion, vacuolar degeneration and myelin loss in white matter, as well as neuronal degeneration. Interstitial fibrosis and previously undescribed granuloma-like lesions were observed in the lungs. Hepatomegaly, steatosis and collagen accumulation were detected in the liver. A whole-exome sequencing of the two unrelated families with the affected children revealed the transmission of two heterozygous variants in the NHL repeat-containing protein 2 (NHLRC2); an amino acid substitution p.Asp148Tyr and a frameshift 2-bp deletion p.Arg201GlyfsTer6. NHLRC2 is highly conserved and expressed in multiple organs and its function is unknown. It contains a thioredoxin-like domain; however, an insulin turbidity assay on human recombinant NHLRC2 showed no thioredoxin activity. In patient-derived fibroblasts, NHLRC2 levels were low, and only p.Asp148Tyr was expressed. Therefore, the allele with the frameshift deletion is likely non-functional. Development of the Nhlrc2 null mouse strain stalled before the morula stage. Morpholino knockdown of nhlrc2 in zebrafish embryos affected the integrity of cells in the midbrain region. This is the first description of a fatal, early-onset disease; we have named it FINCA disease based on the combination of pathological features that include fibrosis, neurodegeneration, and cerebral angiomatosis.

BACKGROUND:Thousands of biomarker tests are either available or under development for lung diseases. In many cases, adoption of these tests into clinical practice is outpacing the generation and evaluation of sufficient data to determine clinical utility and ability to improve health outcomes. There is a need for a systematically organized report that provides guidance on how to understand and evaluate use of biomarker tests for lung diseases.METHODS:We assembled a diverse group of clinicians and researchers from the American Thoracic Society and leaders from the National Heart, Lung, and Blood Institute with expertise in various aspects of precision medicine to review the current status of biomarker tests in lung diseases. Experts summarized existing biomarker tests that are available for lung cancer, pulmonary arterial hypertension, idiopathic pulmonary fibrosis, asthma, chronic obstructive pulmonary disease, sepsis, acute respiratory distress syndrome, cystic fibrosis, and other rare lung diseases. The group identified knowledge gaps that future research studies can address to efficiently translate biomarker tests into clinical practice, assess their cost-effectiveness, and ensure they apply to diverse, real-life populations.RESULTS:We found that the status of biomarker tests in lung diseases is highly variable depending on the disease. Nevertheless, biomarker tests in lung diseases show great promise in improving clinical care. To efficiently translate biomarkers into tests used widely in clinical practice, researchers need to address specific clinical unmet needs, secure support for biomarker discovery efforts, conduct analytical and clinical validation studies, ensure tests have clinical utility, and facilitate appropriate adoption into routine clinical practice.CONCLUSIONS:Although progress has been made toward implementation of precision medicine for lung diseases in clinical practice in certain settings, additional studies focused on addressing specific unmet clinical needs are required to evaluate the clinical utility of biomarkers; ensure their generalizability to diverse, real-life populations; and determine their cost-effectiveness.

Surfactant protein B encoding gene mutations have been related to early onset fatal respiratory distress in fullterm neonates. We report a school-aged male child homozygous for a surfactant protein B encoding gene missense mutation who presented after the neonatal period. His respiratory insufficiency responded to high dose intravenous methylprednisolone and hydroxychloroquine.

Childhood interstitial lung disease (chILD) represents a rare heterogeneous group of respiratory disorders. In the absence of randomized controlled clinical trials, global collaborations have utilized case series with an aim to standardising approaches to diagnosis and management. Australasian data are lacking. The aim of this study was to calculate prevalence and report the experience of chILD in Australasia over a decade.

Mutations of the Surfactant Protein C (SPC) gene (SFTPC) have been associated with childhood interstitial lung disease (chILD) with variable age of onset, severity of lung disease, and outcomes. We report a novel mutation in SFTPC [c.435G->A, p.(Gln145)] that was associated with onset of symptoms in early infancy, progressive respiratory failure with need for prolonged mechanical ventilatory support, and eventual lung transplant at 1 year of age. While the mutation was not predicted to alter the amino acid sequence of the SP-C precursor protein, analysis of SP-C transcripts demonstrated skipping of exon 4. Because of limited data about the outcomes of infants with SFTPC mutations, we conducted a systematic review of all the SFTPC mutations reported in the literature in order to define their presenting features, clinical and radiologic features, and outcomes. Further advances in our understanding of chILD and creation of an international registry will help to track these patients and their outcomes. (C) 2016 Wiley Periodicals, Inc.

Surfactant is a unique lipid and protein substance made by type II cells in the lung that provides inflation stability, decreases the work of breathing, and has components with innate host defense properties. Surfactant is normally synthesized and secreted into the airspaces of the fetal lung as term approaches, but it can be induced earlier in gestation by fetal exposures to corticosteroids or inflammation. The surfactant deficiency associated with preterm birth can cause severe respiratory failure termed respiratory distress syndrome (RDS), a frequently lethal disease before the availability of clinical surfactants to treat infants. Surfactant components each have complex metabolic characteristics in the premature and mature lung. Term infants can have severe surfactant dysfunction because of rare mutations that disrupt surfactant protein synthesis or processing. The research resulting in the understanding of surfactant metabolism and function and subsequent treatment of RDS is a highlight of progress from science to cure strategies in pulmonary medicine.

Interstitial lung diseases in infants and children are uncommon and may be caused by specific inborn errors of surfactant metabolism. Five children with open lung biopsy diagnosed interstitial lung disease were followed (mean of 27.2 years) and evaluated for surfactant protein gene mutations. Four of the children were originally diagnosed as desquamative interstitial pneumonitis and one as chronic interstitial pneumonitis. All had good response to chloroquine or hydroxychloroquine treatment for periods of 7-38 months. Lung function tests, incremental exercise tests, and rentgenological studies were performed in the children. Surfactant protein gene mutations were searched in all the patients and in part of their families. Three of the patients, aged now 32, 29, and 37 years, feel well and have normal lung function, while two of the patients, both females, aged 28 and 37 years, conduct normal activities of daily living, have healthy children but have clinical, physiological and rentgenological evidence of restrictive lung disease. All five patients were found to have surfactant protein C gene (SFTPC) mutations, three of them with the most common mutation (p.I73T) and the other two with new mutations of surfactant protein C gene (p.I38F and p.V39L). We conclude that detection of surfactant protein mutations should be attempted in all children presenting with interstitial lung disease. Furthermore, treatment with hydroxychloroquine should be considered in children with SFTPC mutations. Prospective evaluation of hydroxychloroquine therapy in a greater number of patients is needed. Pediatr Pulmonol. 2014; 49:1097-1105. (c) 2013 Wiley Periodicals, Inc.

Rationale: Recessive mutations in the ATP-binding cassette transporter A3 (ABCA3) cause lethal neonatal respiratory failure and childhood interstitial lung disease. Most ABCA3 mutations are private.Objectives: To determine genotype-phenotype correlations for recessive ABCA3 mutations.Methods: We reviewed all published and unpublished ABCA3 sequence and phenotype data from our prospective genetic studies of symptomatic infants and children at Washington and Johns Hopkins Universities. Mutations were classified based on their predicted disruption of protein function: frameshift and nonsense mutations were classified as "null," whereas missense, predicted splice site mutations, and insertion/deletions were classified as "other." We compared age of presentation and outcomes for the three genotypes: null/null, null/other, and other/other.Measurements and Main Results: We identified 185 infants and children with homozygous or compound heterozygous ABCA3 mutations and lung disease. All of the null/null infants presented with respiratory failure at birth compared with 75% of infants with null/other or other/other genotypes (P = 0.00011). By 1 year of age, all of the null/null infants had died or undergone lung transplantation compared with 62% of the null/other and other/other children (P < 0.0001).Conclusions: Genotype-phenotype correlations exist for homozygous or compound heterozygous mutations in ABCA3. Frameshift or nonsense ABCA3 mutations are predictive of neonatal presentation and poor outcome, whereas missense, splice site, and insertion/deletions are less reliably associated with age of presentation and prognosis. Counseling and clinical decision making should acknowledge these correlations.

Pulmonary surfactant is the mixture of lipids and proteins needed for reducing surface tension in the alveoli at end expiration. Mutations in the genes encoding proteins critical for surfactant function and/or metabolism are rare but important causes of acute and chronic lung disease in children and adults, with disease onset ranging from immediately after birth to well into adulthood. Collectively these disorders are referred to as genetic surfactant dysfunction disorders. This article reviews the known genetic causes of surfactant dysfunction, with emphasis on the clinical presentations of each entity and the implications of the disorders for understanding normal lung cell biology and for other diseases of the lung.

BACKGROUND AND OBJECTIVE: Neonatal respiratory distress syndrome (RDS) due to pulmonary surfactant deficiency is heritable, but common variants do not fully explain disease heritability. METHODS: Using next-generation, pooled sequencing of race-stratified DNA samples from infants $34 weeks’ gestation with and without RDS (n = 513) and from a Missouri population-based cohort (n = 1066), we scanned all exons of 5 surfactant-associated genes and used in silico algorithms to identify functional mutations. We validated each mutation with an independent genotyping platform and compared race-stratified, collapsed frequencies of rare mutations by gene to investigate disease associations and estimate attributable risk. RESULTS: Single ABCA3 mutations were overrepresented among European-descent RDS infants (14.3% of RDS vs 3.7% of non-RDS; P = .002) but were not statistically overrepresented among Africandescent RDS infants (4.5% of RDS vs 1.5% of non-RDS; P = .23). In the Missouri population-based cohort, 3.6% of European-descent and 1.5% of African-descent infants carried a single ABCA3 mutation. We found no mutations among the RDS infants and no evidence of contribution to population-based disease burden for SFTPC, CHPT1, LPCAT1, or PCYT1B. CONCLUSIONS: In contrast to lethal neonatal RDS resulting from homozygous or compound heterozygous ABCA3 mutations, single ABCA3 mutations are overrepresented among European-descent infants $34 weeks’ gestation with RDS and account for ∼10.9% of the attributable risk among term and late preterm infants. Although ABCA3 mutations are individually rare, they are collectively common among Europeanand African-descent individuals in the general population. Pediatrics 2012;130:e1575–e1582 AUTHORS: Jennifer A. Wambach, MD,a Daniel J. Wegner, MS,a Kelcey DePass, BA,a Hillary Heins, BS,a Todd E. Druley, MD, PhD,bc Robi D. Mitra, PhD,c Ping An, MD,d Qunyuan Zhang, PhD,d Lawrence M. Nogee, MD,e F. Sessions Cole, MD,a and Aaron Hamvas, MDa aDivision of Newborn Medicine, bDivision of Hematology and Oncology, the Edward Mallinckrodt Department of Pediatrics, cCenter for Genome Sciences and Systems Biology, Department of Genetics, dDivision of Statistical Genomics, Washington University School of Medicine, St Louis, Missouri; and eDivision of Neonatal–Perinatal Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland

Background: There is growing recognition and understanding of the entities that cause interstitial lung disease (ILD) in infants. These entities are distinct from those that cause ILD in older children and adults. Methods: A multidisciplinary panel was convened to develop evidence-based guidelines on the classification, diagnosis, and management of ILD in children, focusing on neonates and infants under 2 years of age. Recommendations were formulated using a systematic approach. Outcomes considered important included the accuracy of the diagnostic evaluation, complications of delayed or incorrect diagnosis, psychosocial complications affecting the patient's or family's quality of life, and death. Results: No controlled clinical trials were identified. Therefore, observational evidence and clinical experience informed judgments. These guidelines: (1) describe the clinical characteristics of neonates and infants (<2 yr of age) with diffuse lung disease (DLD); (2) list the common causes of DLD that should be eliminated during the evaluation of neonates and infants with DLD; (3) recommend methods for further clinical investigation of the remaining infants, who are regarded as having "childhood ILD syndrome"; (4) describe a new pathologic classification scheme of DLD in infants; (5) outline supportive and continuing care; and (6) suggest areas for future research. Conclusions: After common causes of DLD are excluded, neonates and infants with childhood ILD syndrome should be evaluated by a knowledgeable subspecialist. The evaluation may include echocardiography, controlled ventilation high-resolution computed tomography, infant pulmonary function testing, bronchoscopy with bronchoalveolar lavage, genetic testing, and/or lung biopsy. Preventive care, family education, and support are essential.

Mutations in surfactant-associated genes cause childhood diffuse lung disease. Mice lacking surfactant protein D develop lung disease with age. However, we identified no novel surfactant protein D gene (SFTPD) coding or splice region variants in 73 unrelated children with diffuse lung disease from a cohort enriched for genetic surfactant dysfunction.

ABCA3 (ATP-binding cassette subfamily A, member 3) is expressed in the lamellar bodies of alveolar type II cells and is crucial to pulmonary surfactant storage and homeostasis. ABCA3 gene mutations have been associated with neonatal respiratory distress (NRD) and pediatric interstitial lung disease (ILD). The objective of this study was to look for ABCA3 gene mutations in patients with severe NRD and/or ILD. The 30 ABCA3 coding exons were screened in 47 patients with severe NRD and/or ILD. ABCA3 mutations were identified in 10 out of 47 patients, including 2 homozygous, 5 compound heterozygous and 3 heterozygous patients. SP-B and SP-C expression patterns varied across patients. Among patients with ABCA3 mutations, five died shortly after birth and five developed ILD (including one without NRD). Functional studies of p.D253H and p.T1173R mutations revealed that p.D253H and p.T1173R induced abnormal lamellar bodies. Additionally, p.T1173R increased IL-8 secretion in vitro. In conclusion, we identified new ABCA3 mutations in patients with life-threatening NRD and/or ILD. Two mutations associated with ILD acted via different pathophysiological mechanisms despite similar clinical phenotypes.

BACKGROUND AND OBJECTIVE: Neonatal respiratory distress syndrome (RDS) due to pulmonary surfactant deficiency is heritable, but common variants do not fully explain disease heritability. METHODS: Using next-generation, pooled sequencing of race-stratified DNA samples from infants ≥34 weeks’ gestation with and without RDS (n = 513) and from a Missouri population-based cohort (n = 1066), we scanned all exons of 5 surfactant-associated genes and used in silico algorithms to identify functional mutations. We validated each mutation with an independent genotyping platform and compared race-stratified, collapsed frequencies of rare mutations by gene to investigate disease associations and estimate attributable risk. RESULTS: Single ABCA3 mutations were overrepresented among European-descent RDS infants (14.3% of RDS vs 3.7% of non-RDS; P = .002) but were not statistically overrepresented among African-descent RDS infants (4.5% of RDS vs 1.5% of non-RDS; P = .23). In the Missouri population-based cohort, 3.6% of European-descent and 1.5% of African-descent infants carried a single ABCA3 mutation. We found no mutations among the RDS infants and no evidence of contribution to population-based disease burden for SFTPC, CHPT1, LPCAT1, or PCYT1B. CONCLUSIONS: In contrast to lethal neonatal RDS resulting from homozygous or compound heterozygous ABCA3 mutations, single ABCA3 mutations are overrepresented among European-descent infants ≥34 weeks’ gestation with RDS and account for ∼10.9% of the attributable risk among term and late preterm infants. Although ABCA3 mutations are individually rare, they are collectively common among European- and African-descent individuals in the general population.