The US national registry for childhood interstitial and diffuse lung disease: Report of study design and initial enrollment cohort.

INTRODUCTION: Childhood interstitial and diffuse lung disease (chILD) encompasses a broad spectrum of rare disorders. The Children's Interstitial and Diffuse Lung Disease Research Network (chILDRN) established a prospective registry to advance knowledge regarding etiology, phenotype, natural history, and management of these disorders. METHODS: This longitudinal, observational, multicenter registry utilizes single-IRB reliance agreements, with participation from 25 chILDRN centers across the U.S. Clinical data are collected and managed using the Research Electronic Data Capture (REDCap) electronic data platform. RESULTS: We report the study design and selected elements of the initial Registry enrollment cohort, which includes 683 subjects with a broad range of chILD diagnoses. The most common diagnosis reported was neuroendocrine cell hyperplasia of infancy, with 155 (23%) subjects. Components of underlying disease biology were identified by enrolling sites, with cohorts of interstitial fibrosis, immune dysregulation, and airway disease being most commonly reported. Prominent morbidities affecting enrolled children included home supplemental oxygen use (63%) and failure to thrive (46%). CONCLUSION: This Registry is the largest longitudinal chILD cohort in the United States to date, providing a powerful framework for collaborating centers committed to improving the understanding and treatment of these rare disorders.

Genetic testing for diffuse lung diseases in children.

Newly developing genomic technologies are an increasingly important part of clinical care and thus, it is not only important to understand the technologies and their limitations, but to also interpret the findings in an actionable fashion. Clinical geneticists and genetic counselors are now an integral part of the clinical team and are able to bridge the complexities of this rapidly changing science between the bedside clinicians and patients. This manuscript reviews the terminology, the current technology, some of the known genetic disorders that result in lung disease, and indications for genetic testing with associated caveats. Because this field is evolving quickly, we also provide links to websites that provide continuously updated information important for integrating genomic technology results into clinical decision-making.

Child Interstitial Lung Disease in an Infant with Surfactant Protein C Dysfunction due to c.202G>T Variant (p.V68F).

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.

Accurate assignment of disease liability to genetic variants using only population data.

PURPOSE: The growing size of public variant repositories prompted us to test the accuracy of pathogenicity prediction of DNA variants using population data alone. METHODS: Under the a priori assumption that the ratio of the prevalence of variants in healthy population vs that in affected populations form 2 distinct distributions (pathogenic and benign), we used a Bayesian method to assign probability to a variant belonging to either distribution. RESULTS: The approach, termed Bayesian prevalence ratio (BayPR), accurately parsed 300 of 313 expertly curated CFTR variants: 284 of 296 pathogenic/likely pathogenic variants in 1 distribution and 16 of 17 benign/likely benign variants in another. BayPR produced an area under the receiver operating characteristic curve of 0.99 for 103 functionally confirmed missense CFTR variants, which is equal to or exceeds 10 commonly used algorithms (area under the receiver operating characteristic curve range = 0.54-0.99). Application of BayPR to expertly curated variants in 8 genes associated with 7 Mendelian conditions led to the assignment of a disease-causing probability of ≥80% to 1350 of 1374 (98.3%) pathogenic/likely pathogenic variants and of ≤20% to 22 of 23 (95.7%) benign/likely benign variants. CONCLUSION: Irrespective of the variant type or functional effect, the BayPR approach provides probabilities of pathogenicity for DNA variants responsible for Mendelian disorders using only the variant counts in affected and unaffected population samples.

Genetic Testing for Neonatal Respiratory Disease.

Genetic mechanisms are now recognized as rare causes of neonatal lung disease. Genes potentially responsible for neonatal lung disease include those encoding proteins important in surfactant function and metabolism, transcription factors important in lung development, proteins involved in ciliary assembly and function, and various other structural and immune regulation genes. The phenotypes of infants with genetic causes of neonatal lung disease may have some features that are difficult to distinguish clinically from more common, reversible causes of lung disease, and from each other. Multigene panels are now available that can allow for a specific diagnosis, providing important information for treatment and prognosis. This review discusses genes in which abnormalities are known to cause neonatal lung disease and their associated phenotypes, and advantages and limitations of genetic testing.

Coronavirus Disease 2019 in Pregnancy and Outcomes Among Pregnant Women and Neonates: A Literature Review.

Limited data are available about the outcomes of coronavirus disease 2019 (COVID-19) during pregnancy and risk of vertical transmission in exposed neonates. We reviewed studies published February 1, 2020, through August 15, 2020, on outcomes in pregnant women with COVID-19 and neonates with perinatal exposure. Among pregnant women with COVID-19, 181 (11%) required intensive care unit admission and 123 (8%) required mechanical ventilation. There were 22 maternal deaths. Most infections occurred in the third trimester. Among women who delivered, 28% had a preterm birth, and 57% had a Caesarean section. Sixty-one (4%) of 1222 neonates with reported testing had at least 1 positive severe acute respiratory syndrome coronavirus 2 polymerase chain reaction test. The most common symptom among neonates was respiratory distress (n = 126; 21%). There were 14 neonatal deaths, one of which occurred in a neonate with positive testing. Further study of COVID-19 in pregnant women and neonates, including standardized reporting of outcomes, testing and treatment protocols, is essential to optimize maternal and neonatal care.

Community-Onset Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Young Infants: A Systematic Review.

OBJECTIVE: To summarize and evaluate current reports on community-onset severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in young infants. STUDY DESIGN: We performed a systematic review to identify reports published from November 1, 2019, until June 15, 2020, on laboratory-confirmed community-onset SARS-CoV-2 infection in infants younger than 3 months of age. We excluded studies reporting neonates with perinatal coronavirus disease 2019 (COVID-19) exposure and diagnosis before hospital discharge and hospital-onset disease, as well as clinically diagnosed cases without confirmation. Two independent reviewers performed study screening, data abstraction, and risk of bias assessment. Variables of interest included patient age, exposure to COVID-19, medical history, clinical symptoms, SARS-CoV-2 testing, laboratory findings, clinical course, and disposition. RESULTS: In total, 38 publications met inclusion criteria, including 23 single case reports, 14 case series, and 1 cohort study, describing 63 infants younger than 3 months of age with laboratory-confirmed SARS-CoV-2 infection. Most cases were mild to moderate. Fever, respiratory, gastrointestinal, cardiac, and neurologic findings were reported. Laboratory abnormalities included neutropenia, lymphopenia, and elevated serum levels of inflammatory markers and aminotransferases. Fifty-eight (92%) infants were hospitalized, 13 (21%) were admitted to the intensive care unit, and 2 (3%) required mechanical ventilation. No death was reported. CONCLUSIONS: Among young infants with laboratory-confirmed SARS-CoV-2 infection, most cases were mild to moderate and improved with supportive care. Our results demonstrate a need for a high index of suspicion for SARS-CoV-2 infection in young infants presenting with generalized symptoms such as fever or decreased feeding, even in the absence of respiratory symptoms.

A lung tropic AAV vector improves survival in a mouse model of surfactant B deficiency.

Surfactant protein B (SP-B) deficiency is an autosomal recessive disorder that impairs surfactant homeostasis and manifests as lethal respiratory distress. A compelling argument exists for gene therapy to treat this disease, as de novo protein synthesis of SP-B in alveolar type 2 epithelial cells is required for proper surfactant production. Here we report a rationally designed adeno-associated virus (AAV) 6 capsid that demonstrates efficiency in lung epithelial cell transduction based on imaging and flow cytometry analysis. Intratracheal administration of this vector delivering murine or human proSFTPB cDNA into SP-B deficient mice restores surfactant homeostasis, prevents lung injury, and improves lung physiology. Untreated SP-B deficient mice develop fatal respiratory distress within two days. Gene therapy results in an improvement in median survival to greater than 200 days. This vector also transduces human lung tissue, demonstrating its potential for clinical translation against this lethal disease.

Neonatal respiratory failure due to novel compound heterozygous mutations in the ABCA3 lipid transporter.

The ATP-binding cassette transporter member A3 (ABCA3) is a lipid transporter with a critical function in pulmonary surfactant biogenesis. Biallelic loss-of-function mutations in ABCA3 result in severe surfactant deficiency leading to neonatal respiratory failure with death in the first year of life. Herein, we describe a newborn with severe respiratory distress at birth progressing to respiratory failure requiring transplant. This patient was found to have a maternally inherited frameshift loss-of-function ABCA3 mutation and a paternally inherited synonymous variant in ABCA3 predicted to create a cryptic splice site. Additional studies showed reduced ABCA3 expression in hyperplastic alveolar epithelial type II cells and lamellar body alterations characteristic of ABCA3 deficiency, leading to a diagnosis of autosomal recessive ABCA3-related pulmonary surfactant dysfunction. This case highlights the need for an integrated, comprehensive approach for the diagnosis of inherited diseases when in silico modeling is utilized in the interpretation of key novel genetic mutations.

The common K333Q polymorphism in long-chain acyl-CoA dehydrogenase (LCAD) reduces enzyme stability and function.

The fatty acid oxidation enzyme long-chain acyl-CoA dehydrogenase (LCAD) is expressed at high levels in human alveolar type II (ATII) cells in the lung. A common polymorphism causing an amino acid substitution (K333Q) was previously linked to a loss of LCAD antigen in the lung tissue in sudden infant death syndrome. However, the effects of the polymorphism on LCAD function has not been tested. The present work evaluated recombinant LCAD K333Q. Compared to wild-type LCAD protein, LCAD K333Q exhibited significantly reduced enzymatic activity. Molecular modeling suggested that K333 is within interacting distance of the essential FAD cofactor, and the K333Q protein showed a propensity to lose FAD. Exogenous FAD only partially rescued the activity of LCAD K333Q. LCAD K333Q protein was less stable than wild-type when incubated at physiological temperatures, likely explaining the observation of dramatically reduced LCAD antigen in primary ATII cells isolated from individuals homozygous for K333Q. Despite the effect of K333Q on activity, stability, and antigen levels, the frequency of the polymorphism was not increased among infants and children with lung disease.

Single-Center Outcome of Fetoscopic Tracheal Balloon Occlusion for Severe Congenital Diaphragmatic Hernia.

OBJECTIVE: To assess feasibility and maternal and infant outcome after fetoscopic tracheal balloon occlusion in patients with severe congenital diaphragmatic hernia. METHODS: We conducted a prospective cohort study of fetuses with congenital diaphragmatic hernia and observed/expected lung/head ratio less than 30%. Eligible women had planned fetoscopic tracheal balloon occlusion at 26 0/7-29 6/7 weeks of gestation and balloon removal 4-6 weeks later. Standardized prenatal and postnatal care was at a single institution. Fetoscopic tracheal balloon occlusion details, lung growth, obstetric complications, birth outcome, and infant outcome details until discharge were evaluated. RESULTS: Of 57 women screened, 14 (25%) were enrolled between 2015 and 2019. The congenital diaphragmatic hernia was left in 12 (86%); the pre-fetoscopic tracheal balloon occlusion observed/expected lung/head ratio was 23.2% (range 15.8-29.0%). At a median gestational age of 28 5/7 weeks (range 27 3/7-29 6/7), fetoscopic tracheal balloon occlusion was successful in all cases, and balloons remained in situ. Removal was elective in 10 (71%) patients, by ultrasound-guided needle puncture in eight (57%), and occurred at a median of 33 4/7 weeks of gestation (range 32 1/7-34 4/7; median occlusion 34 days, range 17-44). The post-fetoscopic tracheal balloon occlusion observed/expected lung/head ratio increased to a median of 62.8% (44.0-108) and fell to a median of 46.6% (range 30-92) after balloon removal (all Mann Whitney U, P<.003). For prevention of preterm birth, all patients received vaginal progesterone; 11 (79%) required additional tocolytics, three (21%) had vaginal pessary placement for cervical shortening, and five (36%) had amnioreduction for polyhydramnios. Median gestational age at birth was 39 2/7 weeks (range 33 6/7-39 4/7), with term birth in eight (57%) patients. Twelve (86%) neonates required high-frequency ventilation, and seven (50%) required extracorporeal membrane oxygenation for a median of 7 days (range 3-19). All neonates needed patch repair. Neonatal survival was 93% (n=13, 95% CI 49-100%), and survival to hospital discharge was 86% (n=12, 95% CI 44-100%). CONCLUSION: Fetoscopic tracheal balloon occlusion for severe congenital diaphragmatic hernia was feasible in our single-center setting, with few obstetric complications and favorable infant outcome. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02710968.

El intersticio pulmonar y sus enfermedades en la infancia. Deficiencia de ABCA3. Seguimiento durante doce años. Perspectivas ¿Un nuevo paradigma genético? / The pulmonary interstitium and its diseases in childhood. ABCA3 deficiency. Follow-up for 12 years. Perspectives. A new genetic paradigm?

Introducción. Sobre la base de un caso clínico, se presenta la descripción del cuadro intersticial por deficiencia de ABCA3, de una paciente de catorce años de edad, en seguimiento durante doce años. Método. Evaluación clínica con extensos estudios para descartar otras patologías semejantes. El diagnóstico definitivo fue determinado por el estudio genético para deficiencias de ABCA3 y otros defectos genéticos realizados por el Dr. Larry Nogee, Hospital Johns Hopkins, EE. UU. Objetivos. Describir detalladamente la evolución de la paciente durante doce años, con énfasis en los estudios anteriormente mencionados. Sugerir la presencia de un cambio de paradigma pronóstico en lo que se conocía sobre la evolución de esta enfermedad intersticial pulmonar grave, tratar de mejorar la calidad de vida y posiblemente el pronóstico. Presentar los hallazgos de genética, anatomía patológica y radiología en consultas y evaluaciones por centros de referencia. Resultados. Realizado su diagnóstico de deficiencia genética de ABCA3, presentamos su seguimiento actualizado hasta el año 2020. Esta debe ser sospechada en niños pequeños desde el nacimiento y durante los primeros años ante la persistencia de cuadros pulmonares crónicos con desaturación de oxígeno e imágenes tomográficas que sugieren cuadro intersticial. Se decidió tratar el cuadro en los años 2019-2020, durante seis meses, según bibliografía y consultas con centros de referencia en los Estados Unidos, con la finalidad de determinar la posible mejoría de su patología y decidir la continuación o suspensión de la medicación. Se usaron pulsos con metilprednisolona- hidroxicloroquina y azitromicina. Se logró mantener estable su función pulmonar y mejorar notablemente su calidad de vida. (AU)

Introduction. A clinical case diagnosed with ABCA3 deficiency is described. Patient is now fourteen years old. She´s being followed up since she was two years old. Methodology. clinical follow ­ up with extensive studies to rule out other similar pathologies. Final diagnosis was done through genetic studies done at Johns Hopkins Hospital by Nogee LM. Objective. To present a detailed evolution description of twelve years' follow-up with the support of the aforementioned studies, to suggest a change in diagnostic ­ prognostic paradigm on what was known of mortality in this severe pulmonary interstitial pathology to improve life quality and possibly prognosis. Present the findings of genetics, pathological anatomy and radiology in consultations and evaluations by reference centers. Results. Having made her diagnosis of genetic ABCA3 deficiency, we present her up dated follow-up until 2020. This should be suspected in young children from birth and during the first years due to the persistence of chronic pulmonary symptoms with oxygen desaturation and tomographic images that suggest interstitial symptoms. It was decided to treat the condition in the years 2019-2020, for six months, according to the bibliography and consultations with reference centers in the United States, in order to determine the possible improvement of her pathology and decide to continue or suspend the medication. Pulses with methylprednisolone hydroxychloroquine and azithromycin were used. Her lung function was stable and her quality of life significantly improved. (AU)

Genetic causes of surfactant protein abnormalities.

PURPOSE OF REVIEW: Mutations in genes encoding proteins critical for the production and function of pulmonary surfactant cause diffuse lung disease. Timely recognition and diagnosis of affected individuals is important for proper counseling concerning prognosis and recurrence risk. RECENT FINDINGS: Involved genes include those encoding for surfactant proteins A, B, and C, member A3 of the ATP-binding cassette family, and for thyroid transcription factor 1. Clinical presentations overlap and range from severe and rapidly fatal neonatal lung disease to development of pulmonary fibrosis well into adult life. The inheritance patterns, course, and prognosis differ depending upon the gene involved, and in some cases the specific mutation. Treatment options are currently limited, with lung transplantation an option for patients with end-stage pulmonary fibrosis. Additional genetic disorders with overlapping pulmonary phenotypes are being identified through newer methods, although these disorders often involve other organ systems. SUMMARY: Genetic disorders of surfactant production are rare but associated with significant morbidity and mortality. Diagnosis can be made invasively through clinically available genetic testing. Improved treatment options are needed and better understanding of the molecular pathophysiology may provide insights into treatments for other lung disorders causing fibrosis.

Diagnosis of Primary Ciliary Dyskinesia. An Official American Thoracic Society Clinical Practice Guideline.

BACKGROUND: This document presents the American Thoracic Society clinical practice guidelines for the diagnosis of primary ciliary dyskinesia (PCD). TARGET AUDIENCE: Clinicians investigating adult and pediatric patients for possible PCD. METHODS: Systematic reviews and, when appropriate, meta-analyses were conducted to summarize all available evidence pertinent to our clinical questions. Evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach for diagnosis and discussed by a multidisciplinary panel with expertise in PCD. Predetermined conflict-of-interest management strategies were applied, and recommendations were formulated, written, and graded exclusively by the nonconflicted panelists. Three conflicted individuals were also prohibited from writing, editing, or providing feedback on the relevant sections of the manuscript. RESULTS: After considering diagnostic test accuracy, confidence in the estimates for each diagnostic test, relative importance of test results studied, desirable and undesirable direct consequences of each diagnostic test, downstream consequences of each diagnostic test result, patient values and preferences, costs, feasibility, acceptability, and implications for health equity, the panel made recommendations for or against the use of specific diagnostic tests as compared with using the current reference standard (transmission electron microscopy and/or genetic testing) for the diagnosis of PCD. CONCLUSIONS: The panel formulated and provided a rationale for the direction as well as for the strength of each recommendation to establish the diagnosis of PCD.

NHLRC2 variants identified in patients with fibrosis, neurodegeneration, and cerebral angiomatosis (FINCA): characterisation of a novel cerebropulmonary disease.

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.