Ground glass and fibrotic change in children with surfactant protein C dysfunction mutations.

INTRODUCTION: Therapeutics exist to treat fibrotic lung disease in adults, but these have not been investigated in children. Defining biomarkers for pediatric fibrotic lung disease in children is crucial for clinical trials. Children with surfactant protein C (SFTPC) dysfunction mutations develop fibrotic lung disease over time. We evaluated chest computed tomography (CT) changes over time in children with SFTPC dysfunction mutations. METHODS: We performed an institutional review board-approved retrospective review of children with SFTPC dysfunction mutations. We collected demographic and clinical information. Chest CT scans were evaluated using visual and computerized scores. Chest CT scores and pulmonary function tests were reviewed. RESULTS: Eleven children were included. All children presented in infancy and four children suffered from respiratory failure requiring mechanical ventilation. Those who performed pulmonary function tests had stable forced vital capacities over time by percent predicted, but increased forced vital capacity in liters. CT findings evolved over time in most patients with earlier CT scans demonstrating ground glass opacities and later CT scans with more fibrotic features. In a pilot analysis, data-driven textural analysis software identified fibrotic features in children with SFTPC dysfunction that increased over time and correlated with visual CT scores. DISCUSSION: We describe 11 children with SFTPC dysfunction mutations. Increases in forced vital capacity over time suggest that these children experience lung growth and that therapeutic intervention may maximize lung growth. Ground glass opacities are the primary early imaging findings while fibrotic features dominate later. CT findings suggest the development of and increases in fibrotic features that may serve as potential biomarkers for antifibrotic therapeutic trials.

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.

Expanding the phenotypic and molecular spectrum of RNA polymerase III-related leukodystrophy.

OBJECTIVE: To expand the phenotypic spectrum of severity of POLR3-related leukodystrophy and identify genotype-phenotype correlations through study of patients with extremely severe phenotypes. METHODS: We performed an international cross-sectional study on patients with genetically proven POLR3-related leukodystrophy and atypical phenotypes to identify 6 children, 3 males and 3 females, with an extremely severe phenotype compared with that typically reported. Clinical, radiologic, and molecular features were evaluated for all patients, and functional and neuropathologic studies were performed on 1 patient. RESULTS: Each patient presented between 1 and 3 months of age with failure to thrive, severe dysphagia, and developmental delay. Four of the 6 children died before age 3 years. MRI of all patients revealed a novel pattern with atypical characteristics, including progressive basal ganglia and thalami abnormalities. Neuropathologic studies revealed patchy areas of decreased myelin in the cerebral hemispheres, cerebellum, brainstem, and spinal cord, with astrocytic gliosis in the white matter and microglial activation. Cellular vacuolization was observed in the thalamus and basal ganglia, and neuronal loss was evident in the putamen and caudate. Genotypic similarities were also present between all 6 patients, with one allele containing a POLR3A variant causing a premature stop codon and the other containing a specific intronic splicing variant (c.1771-7C>G), which produces 2 aberrant transcripts along with some wild-type transcript. CONCLUSIONS: We describe genotype-phenotype correlations at the extreme end of severity of the POLR3-related leukodystrophy spectrum and shed light on the complex disease pathophysiology.

A Long-Term Survivor With Alveolar Capillary Dysplasia.

A patient with alveolar capillary dysplasia has survived more than 56 months with medical therapy. Intrauterine exposure to metformin potentially modified the severity of disease. In combination with other agents, endothelin receptor antagonists and amlodipine have been key medications in lowering pulmonary arterial pressure and managing right heart failure. (Level of Difficulty: Beginner.).

Isolated pulmonary interstitial glycogenosis associated with alveolar growth abnormalities: A long-term follow-up study.

INTRODUCTION: Pulmonary interstitial glycogenosis (PIG) is a rare infant interstitial lung disease characterized by an increase in the number of interstitial mesenchymal cells, presenting as enhanced cytoplasmic glycogen, and is considered to represent the expression of an underlying lung development disorder. METHODS: This study describes the clinical, radiological, and functional characteristics and long-term outcomes (median 12 years) of nine infants diagnosed with isolated PIG associated with alveolar simplification in the absence of other diseases. RESULTS: All patients presented with tachypnea. Additionally, seven patients had breathing difficulties and hypoxemia. Abnormalities in chest-computerized tomography (CT) with a pattern of ground-glass opacity, septal thickening, and air trapping were observed in all individuals, with images suggesting abnormal alveolar growth (parenchymal bands and architectural distortion). All lung biopsies showed alveolar simplification associated with an increased number of interstitial cells, which appeared as accumulated cytoplasmic glycogen. In the follow-up, all patients were asymptomatic. The respiratory function test was normal in only two patients. Five children showed an obstructive pattern, and two children showed a restrictive pattern. Chest-CT, performed after an average of 6.5 years since the initial investigation, revealed a partial improvement of the ground-glass opacity pattern; however, relevant alterations persisted. CONCLUSION: Although the patients with PIG in the absence of other associated pathologies had a good clinical outcome, significant radiographic alterations and sequelae in lung function were still observed after a median follow-up of 12 years, suggesting that PIG is a marker of some other persistent abnormalities in lung growth, which have effects beyond the symptomatic period.

Pathogenic variants in glutamyl-tRNAGln amidotransferase subunits cause a lethal mitochondrial cardiomyopathy disorder.

Mitochondrial protein synthesis requires charging mt-tRNAs with their cognate amino acids by mitochondrial aminoacyl-tRNA synthetases, with the exception of glutaminyl mt-tRNA (mt-tRNAGln). mt-tRNAGln is indirectly charged by a transamidation reaction involving the GatCAB aminoacyl-tRNA amidotransferase complex. Defects involving the mitochondrial protein synthesis machinery cause a broad spectrum of disorders, with often fatal outcome. Here, we describe nine patients from five families with genetic defects in a GatCAB complex subunit, including QRSL1, GATB, and GATC, each showing a lethal metabolic cardiomyopathy syndrome. Functional studies reveal combined respiratory chain enzyme deficiencies and mitochondrial dysfunction. Aminoacylation of mt-tRNAGln and mitochondrial protein translation are deficient in patients' fibroblasts cultured in the absence of glutamine but restore in high glutamine. Lentiviral rescue experiments and modeling in S. cerevisiae homologs confirm pathogenicity. Our study completes a decade of investigations on mitochondrial aminoacylation disorders, starting with DARS2 and ending with the GatCAB complex.

Pulmonary interstitial glycogenosis: Diagnostic evaluation and clinical course.

OBJECTIVES: We sought to describe the phenotype for patients with P.I.G. including presentation, evaluation, cardiac co-morbidities, high resolution computed tomography findings, and outcomes. METHODS: With institutional review board approval, we performed a retrospective review of patients with biopsy-proven P.I.G. Biopsies, high resolution chest computed tomography, and cardiac evaluations were reviewed and characterized by experts in each field. RESULTS: Sixty-two percent of the patients were male. The median gestational age was 37 weeks (range 27-40). The median age at biopsy was 1.6 months (range 0.3-6 months). Structural heart disease was present in 63% of patients. Pulmonary hypertension (diagnosed by echocardiogram and/or cardiac catheterization) was noted in 38% of patients. Alveolar simplification was present in 79% of patients. Fifty percent of available biopsies revealed patchy disease. An increase in age at biopsy was associated with patchy (vs diffuse) disease. Ninety-two percent of patients were treated with systemic corticosteroids. Median age at last follow-up was 1234 days with a range of 37 days to 15 years. At the time of last follow-up, 12 patients were off all support, eight were on supplemental oxygen, two were mechanically ventilated, one underwent lung transplantation, and one died. CT findings commonly included ground glass opacities (86%) and cystic change (50%). CONCLUSIONS: The P.I.G. phenotype has not been comprehensively described, and poor recognition and misconceptions about P.I.G. persist. P.I.G. is a disease that presents in early infancy, requires significant medical intervention, and frequently is seen in association with alveolar simplification and/or cardiovascular disease. CT findings include ground glass opacities and cysts. Patients should be monitored for pulmonary hypertension. Without life-threatening comorbidities, many patients do well over time, although respiratory symptoms may persist into adolescence.

Respiratory distress in a 2-month-old infant: Is the primary cause cardiac, pulmonary or both?

A 2-month-old female with worsening cough, respiratory distress and an abnormal chest X-ray was referred to our institution for further evaluation of suspected scimitar syndrome. She was found to have normal pulmonary venous drainage with a large patent ductus arteriosus and severe pulmonary arterial hypertension. Chest CT was suggestive of interstitial lung disease. Wedge lung biopsy revealed alveolar simplification and patchy pulmonary interstitial glycogenosis. A definitive diagnosis of Filamin A deficiency was made with genetic studies. The patient is currently showing clinical improvement on systemic glucocorticoid therapy.

The Emergence of Zoonotic Onchocerca lupi Infection in the United States--A Case-Series.

This case-series describes the 6 human infections with Onchocerca lupi, a parasite known to infect cats and dogs, that have been identified in the United States since 2013. Unlike cases reported outside the country, the American patients have not had subconjunctival nodules but have manifested more invasive disease (eg, spinal, orbital, and subdermal nodules). Diagnosis remains challenging in the absence of a serologic test. Treatment should be guided by what is done for Onchocerca volvulus as there are no data for O. lupi. Available evidence suggests that there may be transmission in southwestern United States, but the risk of transmission to humans is not known. Research is needed to better define the burden of disease in the United States and develop appropriately-targeted prevention strategies.

A pediatric case of mammary analogue secretory carcinoma within the parotid.

Mammary analogue secretory carcinoma (MASC) is a recently described entity in the differential diagnosis of salivary gland tumors. It is notable for a characteristic t(12;15)(p13;q25) translocation that results in a unique fusion protein, ETV6-NTRK3. While several studies have retrospectively identified this translocation in cases previously diagnosed as a different salivary malignancy, there have been relatively few cases where this translocation was identified on initial pathology results, and fewer still in a pediatric population. We present a case of a 15 year old female with a slowly enlarging, painless, left facial mass. MRI demonstrated a cystic mass extending into the deep lobe of the parotid, and she underwent parotidectomy. The tumor cells stained positive for S100 and CK19. ETV6 translocation was present, confirming the diagnosis. Mammary analogue secretory carcinoma is a recently described tumor of the salivary glands, which often masquerades as more common primary salivary gland tumors and cysts. More research is needed to characterize the typical behavior of this neoplasm and the optimal treatment regimen. With identification of its characteristic translocation, mammary analogue secretory carcinoma can be easily differentiated from its more prevalent counterparts, and should therefore remain within the differential of the pathologist and head and neck surgeon.

Late Onset Hypomorphic RAG2 Deficiency Presentation with Fatal Vaccine-Strain VZV Infection.

PURPOSE: Hypomorphic mutations in RAG1 and RAG2 are associated with significant clinical heterogeneity and symptoms of immunodeficiency or autoimmunity may be late in appearance. As a result, immunosuppressive medications may be introduced that can have life-threatening consequences. We describe a previously healthy 13-month-old girl presenting with rash and autoimmune hemolytic anemia, while highlighting the importance of vigilance and consideration of an underlying severe immunodeficiency disease prior to instituting immunosuppressive therapy. METHODS: Given clinical deterioration of the patient and a temporal association with recently administered vaccinations, virus genotyping was carried out via 4 real-time Forster Resonance Energy Transfer PCR protocols targeting vaccine-associated single nucleotide polymorphisms. Genomic DNA was extracted from whole blood and analyzed via the next-generation sequencing method of sequencing-by-synthesis. Immune function studies included immunophenotyping of peripheral blood lymphocytes, mitogen-induced proliferation and TLR ligand-induced production of TNFα. Analysis of recombination activity of wild-type and mutant RAG2 constructs was performed. RESULTS: Virus genotyping revealed vaccine-strain VZV, mumps, and rubella. Next-generation sequencing identified heterozygosity for RAG2 R73H and P180H mutations. Profound lymphopenia was associated with intense corticosteroid therapy, with some recovery after steroid reduction. Residual, albeit low, RAG2 protein activity was demonstrated. CONCLUSIONS: Because of the association of RAG deficiency with late-onset presentation and autoimmunity, live virus vaccination and immunosuppressive therapies are often initiated and can result in negative consequences. Here, hypomorphic RAG2 mutations were linked to disseminated vaccine-strain virus infections following institution of corticosteroid therapy for autoimmune hemolytic anemia.

Diffuse Lung Disease in Biopsied Children 2 to 18 Years of Age. Application of the chILD Classification Scheme.

RATIONALE: Children's Interstitial and Diffuse Lung Disease (chILD) is a heterogeneous group of disorders that is challenging to categorize. In previous study, a classification scheme was successfully applied to children 0 to 2 years of age who underwent lung biopsies for chILD. This classification scheme has not been evaluated in children 2 to 18 years of age. OBJECTIVES: This multicenter interdisciplinary study sought to describe the spectrum of biopsy-proven chILD in North America and to apply a previously reported classification scheme in children 2 to 18 years of age. Mortality and risk factors for mortality were also assessed. METHODS: Patients 2 to 18 years of age who underwent lung biopsies for diffuse lung disease from 12 North American institutions were included. Demographic and clinical data were collected and described. The lung biopsies were reviewed by pediatric lung pathologists with expertise in diffuse lung disease and were classified by the chILD classification scheme. Logistic regression was used to determine risk factors for mortality. MEASUREMENTS AND MAIN RESULTS: A total of 191 cases were included in the final analysis. Number of biopsies varied by center (5-49 biopsies; mean, 15.8) and by age (2-18 yr; mean, 10.6 yr). The most common classification category in this cohort was Disorders of the Immunocompromised Host (40.8%), and the least common was Disorders of Infancy (4.7%). Immunocompromised patients suffered the highest mortality (52.8%). Additional associations with mortality included mechanical ventilation, worse clinical status at time of biopsy, tachypnea, hemoptysis, and crackles. Pulmonary hypertension was found to be a risk factor for mortality but only in the immunocompetent patients. CONCLUSIONS: In patients 2 to 18 years of age who underwent lung biopsies for diffuse lung disease, there were far fewer diagnoses prevalent in infancy and more overlap with adult diagnoses. Immunocompromised patients with diffuse lung disease who underwent lung biopsies had less than 50% survival at time of last follow-up.

Clinical and biochemical characterization of four patients with mutations in ECHS1.

BACKGROUND: Short-chain enoyl-CoA hydratase (SCEH, encoded by ECHS1) catalyzes hydration of 2-trans-enoyl-CoAs to 3(S)-hydroxy-acyl-CoAs. SCEH has a broad substrate specificity and is believed to play an important role in mitochondrial fatty acid oxidation and in the metabolism of branched-chain amino acids. Recently, the first patients with SCEH deficiency have been reported revealing only a defect in valine catabolism. We investigated the role of SCEH in fatty acid and branched-chain amino acid metabolism in four newly identified patients. In addition, because of the Leigh-like presentation, we studied enzymes involved in bioenergetics. METHODS: Metabolite, enzymatic, protein and genetic analyses were performed in four patients, including two siblings. Palmitate loading studies in fibroblasts were performed to study mitochondrial ß-oxidation. In addition, enoyl-CoA hydratase activity was measured with crotonyl-CoA, methacrylyl-CoA, tiglyl-CoA and 3-methylcrotonyl-CoA both in fibroblasts and liver to further study the role of SCEH in different metabolic pathways. Analyses of pyruvate dehydrogenase and respiratory chain complexes were performed in multiple tissues of two patients. RESULTS: All patients were either homozygous or compound heterozygous for mutations in the ECHS1 gene, had markedly reduced SCEH enzymatic activity and protein level in fibroblasts. All patients presented with lactic acidosis. The first two patients presented with vacuolating leukoencephalopathy and basal ganglia abnormalities. The third patient showed a slow neurodegenerative condition with global brain atrophy and the fourth patient showed Leigh-like lesions with a single episode of metabolic acidosis. Clinical picture and metabolite analysis were not consistent with a mitochondrial fatty acid oxidation disorder, which was supported by the normal palmitate loading test in fibroblasts. Patient fibroblasts displayed deficient hydratase activity with different substrates tested. Pyruvate dehydrogenase activity was markedly reduced in particular in muscle from the most severely affected patients, which was caused by reduced expression of E2 protein, whereas E2 mRNA was increased. CONCLUSIONS: Despite its activity towards substrates from different metabolic pathways, SCEH appears to be only crucial in valine metabolism, but not in isoleucine metabolism, and only of limited importance for mitochondrial fatty acid oxidation. In severely affected patients SCEH deficiency can cause a secondary pyruvate dehydrogenase deficiency contributing to the clinical presentation.

Factors that increase diagnostic yield of surgical lung biopsy in pediatric oncology patients.

PURPOSE: Recent data demonstrate that surgical lung biopsy in immunocompromised children, including oncology patients, alters therapy in only 50% of cases. We hypothesized that there are factors identifiable preoperatively which can predict the patients who will or will not benefit from surgical biopsy. METHODS: We reviewed the medical records of all children with malignancy who underwent surgical lung biopsy between 2004 and 2013 at a single institution, excluding those children who had previously undergone a solid organ or bone marrow transplant. RESULTS: Eighty lung wedge biopsies were performed (median age 13 years, IQR 5.25-16; 63% male, n=50) 53 (66%) of which led to a change in patient management. The majority of biopsies were performed to diagnose a new mass or differentiate infection from metastases (mass group) (n=68, 85%), and 12 biopsies (15%) were performed to diagnose a known infection for antibiotic guidance (infection group). Children in the infection group were more likely to be febrile preoperatively, were more likely to be an inpatient preoperatively, and had a lower absolute neutrophil count at the time of biopsy. Patients in the infection group had higher postoperative mortality rates and higher rates of major complications. CONCLUSION: In pediatric oncology patients, surgical lung biopsy has a lower diagnostic yield and higher complication rate when performed for antibiotic guidance. Prior to proceeding with biopsy in this high-risk patient population, surgeons and oncologists should carefully weigh the potential risks and benefits.

MUC5B expression and location in surfactant protein C mutations in children.

BACKGROUND: Mutations in Surfactant Protein C (SFTPC) can lead to fibrotic interstitial lung disease (ILD) with variable phenotypes, especially in children. The sources of phenotype variability are incompletely understood. A common MUC5B promoter variant rs35705950 is associated with adult Idiopathic Pulmonary Fibrosis (IPF). We examined whether MUC5B is similarly linked to ILD secondary to SFTPC mutations. METHODS: MUC5B concentration in bronchoalveolar lavage fluid (BALF) was measured in six pediatric patients with SFTPC mutations and diseased controls. Immunohistochemical localization of MUC5B was studied in fixed lung tissues in patients with SFTPC mutations, ABCA3 mutations, and controls. Genotyping for the MUC5B promoter variant rs35705950 was attempted in all samples. RESULTS: MUC5B glycoprotein was increased in BALF of patients with SFTPC mutations compared to diseased controls (P = 0.04). MUC5B was unexpectedly present in cells morphologically consistent with alveolar epithelial type II cells in patients with SFTPC mutations in the BRICHOS domain. Genotyping for the MUC5B promoter variant was successful in 18/27 patients, and there was no significant relationship between the MUC5B promoter variant and the BALF or MUC5B localization. CONCLUSION: MUC5B may play a role in the development of fibrosis in patients with SFTPC mutations, especially in patients with BRICHOS mutations. Understanding the role of MUC5B in adult and pediatric lung diseases may lead to a better understanding of the etiology of fibrotic lung disease as well as development of novel therapies.

Taquipnea persistente en un lactante por hiperplasia de células neuroendocrinas pulmonares / Persistent tachypnea of infancy and pulmonary neuroendocrine cells hyperplasia

Introducción. Sobre la base de un caso clínico se presenta la descripción de un cuadro intersticial pulmonar por hiperplasia de células neuroendocrinas en un lactante. Método. Seguimiento clínico desde el sexto mes hasta los 17 meses con extensos estudios para descartar otras patologías semejantes. El diagnóstico definitivo fue determinado por taquipnea persistente y rales crepitantes con imágenes en vidrio esmerilado características, en lóbulo medio y língula. La biopsia pulmonar fue “normal” a la observación con microscopio óptico a pesar de las imágenes evidentes en TAC. La tinción con bombesina demostró acumulaciones anormales de células neuroendocrinas de 10,9% en bronquiolos e hiperinsuflación (Children’s Hospital of Colorado). Resultados. Se confirmó en este lactante con síntomas de cuadro intersticial la patología pulmonar sospechada: hiperplasia de células neuroendocrinas. Ésta debe ser sospechada en un lactante con: taquipnea, rales crepitantes persistentes, posible desnutrición, radiografía hiperinsuflada, tomografía que muestra imágenes en mosaico tipo vidrio esmerilado especialmente en lóbulo medio y língula. Biopsia pulmonar casi normal y aumento porcentual de células neuroendocrinas en bronquios periféricos.

Introduction. A clinical case of a 6 month old infant with symptoms of interstitial lung disease is presented. Methodology. Follow up until 17 months of age is described. Extensive studies were included to rule out other similar pathologies of infancy. Final diagnosis was determined by characteristic clinical symptomatology of persistent tachypnea and crepitant rales, hyperinflated chest x rays, CT scan presenting ground glass opacities in the middle lobe and lingula. Lung biopsy was nearly normal and bombesin staining showed increased percentage of neuroendocrine bronchial cells (10.9%) (Children’s Hospital of Colorado). Results. NEHI was confirmed in this 6 months old infant. This diagnosis should be suspected in a tachypneic infant, with persistent fine rales, possible undernutrition, chest x-rays hyperinflation and CT scan with ground glass opacities more characteristically in middle lobe and lingula. Lung biopsy is near normal but staining with bombesin shows increased number of neuroendocrine cells and neuroendocrine bodies.

Intrapulmonary vascular shunt pathways in alveolar capillary dysplasia with misalignment of pulmonary veins.

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a lethal neonatal lung disease characterised by severe pulmonary hypertension, abnormal vasculature and intractable hypoxaemia. Mechanisms linking abnormal lung vasculature with severe hypoxaemia in ACD/MPV are unknown. We investigated whether bronchopulmonary anastomoses form right-to-left shunt pathways in ACD/MVP. We studied 2 infants who died of ACD/MPV postmortem with direct injections of coloured ink into the pulmonary artery, bronchial artery and pulmonary veins. Extensive histological evaluations included serial sectioning, immunostaining and 3-dimensional reconstruction demonstrated striking intrapulmonary vascular pathways linking the systemic and pulmonary circulations that bypass the alveolar capillary bed. These data support the role of prominent right-to-left intrapulmonary vascular shunt pathways in the pathophysiology of ACD/MPV.

Multicentric Castleman disease presenting with fever.

Multicentric Castleman disease (MCD) is a rare lymphoproliferative disorder that usually manifests with nonspecific symptoms, including fever and lymphadenopathy. Treatment of pediatric MCD varies greatly. A 21-month-old child was diagnosed with MCD after presenting with fever. He had incomplete response to initial therapy directed at interleukin-6, but improved with subsequent chemotherapy.