PRO-C3, a Serological Marker of Fibrosis, During Childhood and Correlations With Fibrosis in Pediatric NAFLD.

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease in children and may lead to cirrhosis requiring liver transplant. Thus, prompt diagnosis of advanced fibrosis is essential. Our objectives were to examine PRO-C3 (a neo-epitope pro-peptide of type III collagen formation) levels across childhood/adolescence and associations with advanced fibrosis in pediatric NAFLD. This cross-sectional study included 88 children and adolescents with biopsy-proven NAFLD (mean age: 13.9 ± 2.9 years, 71% male) and 65 healthy participants (11.8 ± 4.5 years, 38% male). PRO-C3, and the bone remodeling biomarkers C-terminal telopeptide of type I collagen (CTX-I; bone resorption) and osteocalcin (N-MID; bone formation), were measured in serum by enzyme-linked immunosorbent assay. Fibrosis was assessed by liver biopsy in participants with NAFLD, who were categorized as having advanced (Ishak score ≥ 3) or none/mild fibrosis (Ishak score ≤ 2). Overall, PRO-C3 was similar in participants with NAFLD (median [interquartile range]: 20.6 [15.8, 25.9] ng/mL) versus healthy participants (19.0 [13.8, 26.0] ng/mL), but was significantly lower in older adolescents ≥ 15 years old (16.4 [13.0, 21.2] ng/mL) compared with children ≤ 10 years old (22.9 [18.1, 28.4] ng/mL; P < 0.001) or 11-14 years old (22.4 [18.3, 31.2] ng/mL; P < 0.001). PRO-C3 was also directly correlated with levels of CTX-I and N-MID (r = 0.64 and r = 0.62, respectively; both P < 0.001). Among participants with NAFLD, PRO-C3 was higher in those with advanced fibrosis (median [IQR]: 28.5 [21.6, 37.6]) compared with none/mild fibrosis (20.3 [18.2, 22.8]; P = 0.020) in models adjusted for age, sex, and body mass index z-score. However, associations were attenuated after additionally adjusting for bone-remodeling CTX-I (P = 0.09) or N-MID (P = 0.08). Conclusion: Collectively, these findings show that PRO-C3 levels are higher in children with advanced fibrosis in NAFLD, but are also influenced by age and pubertal growth spurt, assessed by bone remodeling biomarkers, and therefore may not be a reliable biomarker for liver fibrosis in pediatric NAFLD until late adolescence.

Bronchoscopic interventions for plastic bronchitis in children without structural heart disease.

Plastic bronchitis (PB) is a rare and life-threatening complication encountered in several disease states that leads to airway obstruction by branching casts. PB is most often reported in children with cyanotic congenital heart disease where recurrence is common, and mortality is high. There is limited data on optimal management strategies or recurrence of non-structural heart disease-related PB in children. We describe the clinical features, management, and outcomes in our cohort of children with non-structural heart disease-related PB. Among the 12 identified patients, asthma was the most common (67%) diagnosis. Ventilatory requirements ranged from room air to one patient who required extracorporeal membrane oxygenation (ECMO). Most patients (92%) required bronchoscopy, and cryotherapy was successfully utilized in two patients to relieve refractory obstructive airway casts. All patients received chest physiotherapy, and 11 patients were treated with two or more medications. There was one mortality despite ECMO, and one-third had recurrent PB, all of whom had asthma.Conclusion: Asthma is a risk factor for recurrent PB. Bronchoscopic interventions including cryotherapy are safe and effective treatment options in patients with refractory PB. What is Known: • Plastic bronchitis is a rare but life-threatening cause of airway obstruction caused by branching casts that are generally reported in patients with congenital heart disease. What is New: • In children without structural heart disease, asthma is a risk factor for recurrent plastic bronchitis. Cryotherapy via bronchoscopy is a safe and effective intervention in patients with refractory plastic bronchitis.

Pretransplantation and Post-Transplantation Liver Disease Assessment in Adolescents Undergoing Isolated Heart Transplantation for Fontan Failure.

OBJECTIVE: To describe the assessment of Fontan-associated liver disease and determine the clinical and imaging measures that may identify hepatic morbidity risk in isolated heart transplantation candidates and trend those measures post-isolated heart transplantation. STUDY DESIGN: Retrospective analysis of pre-isolated heart transplantation and post-isolated heart transplantation Fontan-associated liver disease (FALD) status using blood tests, magnetic resonance imaging (MRI), and liver biopsy analysis within 6 months before isolated heart transplantation and 12 months after isolated heart transplantation in 9 consecutive patients with Fontan. Pre- and post-isolated heart transplantation standard laboratory values; varices, ascites, splenomegaly, thrombocytopenia (VAST) score; Fontan liver MRI score; liver biopsy scores; Model for End-stage Liver Disease (MELD); MELD excluding the International Normalized Ratio (MELD-XI); AST to platelet ratio index, and cardiac catheterization data were compared. RESULTS: Pretransplantation maximum MELD and MELD-XI was 15 and 16, respectively. Central venous pressures and VAST scores decreased significantly post-transplantation. In 5 paired studies, Fontan liver MRI score maximum was 10 pretransplantation and decreased significantly post-transplantation. Arterially enhancing nodules on MRI persisted in 2 patients post-transplantation. Pretransplantation and post-transplantation liver biopsy scores did not differ in 4 paired biopsy specimens. CONCLUSIONS: Patients with FALD and MELD <15, MELD-XI <16, Fontan liver MRI score <10, and VAST score ≤2 can have successful short-term isolated heart transplantation outcomes. Liver MRI and VAST scores improved post-transplantation. Post-transplantation liver biopsy scores did not change significantly. Pretransplantation liver biopsy demonstrating fibrosis alone should not exclude consideration of isolated heart transplantation. The persistence of hepatic vascular remodeling and fibrosis post-isolated heart transplantation suggests that continued surveillance for hepatic complications post-transplantation for patients with Fontan is reasonable.

Increased atherogenic lipoprotein profile in children with non-alcoholic steatohepatitis.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) has been shown to be an independent risk factor for cardiovascular disease. In adults, histologic severity of non-alcoholic steatohepatitis (NASH) is associated with a more atherogenic profile. OBJECTIVE: To assess cardiovascular disease risk by lipoprotein profile in children with NAFLD and compare to histologic assessment of severity. METHODS: Nuclear magnetic resonance lipoprotein profile including lipoprotein particle sizes, apolipoproteins and the lipoprotein insulin resistance (LP-IR) index was measured in serum samples collected from 76 children at the time of a clinically indicated liver biopsy for NAFLD. Liver histology was scored using the NASH Clinical Research Network criteria and grouped into NASH or non-NASH. RESULTS: Children with NASH had higher apolipoprotein B to apolipoprotein AI, ApoB/ApoAI (0.56 [IQR, 0.45-0.70] vs 0.66 [IQR, 0.56-0.79], P = .02) and higher LP-IR index (61 ± 21.9 vs 68 ± 17.3, P = .05) compared to children with non-NASH. Severity of hepatocyte ballooning was associated with higher ApoB/ApoAI ratios (P = .01), while high-density lipoprotein size was inversely associated with hepatic fat accumulation (P = .04). CONCLUSION: While dyslipidaemia is common among children with NAFLD, this data suggests severity of the histologic features is closely associated with severity of cardiometabolic risk. Further studies are needed to understand the role of treatment of NASH in children to prevent future cardiometabolic disease.

Development of a Plasma Screening Panel for Pediatric Nonalcoholic Fatty Liver Disease Using Metabolomics.

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children, but diagnosis is challenging due to limited availability of noninvasive biomarkers. Machine learning applied to high-resolution metabolomics and clinical phenotype data offers a novel framework for developing a NAFLD screening panel in youth. Here, untargeted metabolomics by liquid chromatography-mass spectrometry was performed on plasma samples from a combined cross-sectional sample of children and adolescents ages 2-25 years old with NAFLD (n = 222) and without NAFLD (n = 337), confirmed by liver biopsy or magnetic resonance imaging. Anthropometrics, blood lipids, liver enzymes, and glucose and insulin metabolism were also assessed. A machine learning approach was applied to the metabolomics and clinical phenotype data sets, which were split into training and test sets, and included dimension reduction, feature selection, and classification model development. The selected metabolite features were the amino acids serine, leucine/isoleucine, and tryptophan; three putatively annotated compounds (dihydrothymine and two phospholipids); and two unknowns. The selected clinical phenotype variables were waist circumference, whole-body insulin sensitivity index (WBISI) based on the oral glucose tolerance test, and blood triglycerides. The highest performing classification model was random forest, which had an area under the receiver operating characteristic curve (AUROC) of 0.94, sensitivity of 73%, and specificity of 97% for detecting NAFLD cases. A second classification model was developed using the homeostasis model assessment of insulin resistance substituted for the WBISI. Similarly, the highest performing classification model was random forest, which had an AUROC of 0.92, sensitivity of 73%, and specificity of 94%. Conclusion: The identified screening panel consisting of both metabolomics and clinical features has promising potential for screening for NAFLD in youth. Further development of this panel and independent validation testing in other cohorts are warranted.

Multilocus Heterotopic Gastric Mucosa of Ileum Masquerading as VEOIBD in a Newborn.

Heterotopic gastric mucosa (HGM) is defined as the presence of gastric mucosa outside of the stomach, which is documented by histologic finding. HGM is typically a solitary lesion; however, in our Case Report, the patient presented with multilocus HGM, an uncommon form in which the small bowel is extensively involved. We report a unique case of multilocus HGM mimicking very early-onset inflammatory bowel disease with recurrent gastrointestinal bleeding, chronic inflammation, and stricturing in a newborn patient. Histologic findings from the ileocecal specimen revealed multiple ulcers surrounded by chronic inflammation. Subsequently, a Technetium-99m pertechnetate scan demonstrated an increased tracer uptake in the remaining ileum. This radiologic finding, in combination with the discovery of gastric mucosa within the remainder of resected ileal specimen, led to the diagnosis of HGM. Omeprazole was initiated, and the patient is now asymptomatic without further gastrointestinal bleeding. Increased awareness of this rare disease and performing a Technetium-99m pertechnetate early can correctly diagnose HGM and prevent disease complication.

Diagnosis and Management of Children With Mycobacterium abscessus Infections in the Head and Neck.

PURPOSE: Controversy exists regarding the most appropriate treatment strategy for children with nontuberculous mycobacterial (NTM) cervical lymphadenitis. Mycobacterium abscessus (MAB) is an uncommon cause of NTM cervical lymphadenitis. The purpose of the present study was to evaluate diagnosis, management, and treatment outcomes in children with MAB-associated cervical lymphadenitis resulting from a pulpotomy. MATERIALS AND METHODS: This was a retrospective chart review of children with NTM lymphadenitis of the head and neck caused by MAB treated at Children's Healthcare of Atlanta hospitals (Atlanta, GA). The predictor variables were patient demographics, dental history, clinical presentation, imaging characteristics, laboratory findings, histopathologic examination, treatment, and complications. The outcome variable was disease resolution or persistence. RESULTS: Twenty-two patients (mean age, 6.5 yr) met the inclusion criteria. All patients had pulpotomy at 1 dental practice. The mean time from dental procedure to symptom onset was 43.1 days (range, 3 to 180 days). Children presented with cervical or submandibular swelling, facial swelling, gingival erythema, and skin erythema. Radiographic findings were submandibular or cervical lymphadenitis, maxillary or mandibular osteolysis, subcutaneous abscess, and pulmonary nodules. All children had confirmed or probable MAB infection diagnosed on the pathologic specimen. There were 2 distinct patient presentations that guided surgical management: isolated noninflammatory cervical lymphadenitis, which was partly or completely excised (n = 11), and adjacent extension or disseminated infection requiring subtotal lymph node excision, bone debridement, and postoperative antibiotics (n = 11). Most children required multiple surgical interventions to remove infected tissues. All achieved clinical resolution. CONCLUSION: In this cohort, treatment of NTM lymphadenitis caused by MAB depended on extent of disease and virulence of bacteria. When complete surgical excision was possible, disease resolution was achieved. However, in cases with adjacent extension or dissemination infection, postoperative antibiotics were necessary.

Low Hepatic Tissue Copper in Pediatric Nonalcoholic Fatty Liver Disease.

OBJECTIVE: Animal models and studies in adults have demonstrated that copper restriction increases severity of liver injury in nonalcoholic fatty liver disease (NAFLD). This has not been studied in children. We aimed to determine if lower tissue copper is associated with increased NAFLD severity in children. METHODS: This was a retrospective study of pediatric patients who had a liver biopsy including a hepatic copper quantitation. The primary outcome compared hepatic copper concentration in NAFLD versus non-NAFLD. Secondary outcomes compared hepatic copper levels against steatosis, fibrosis, lobular inflammation, balloon degeneration, and NAFLD activity score (NAS). RESULTS: The study analysis included 150 pediatric subjects (102 with NAFLD and 48 non-NAFLD). After adjusting for age, body mass index z score, gamma glutamyl transferase, alanine aminotransferase, and total bilirubin, NAFLD subjects had lower levels of hepatic copper than non-NAFLD (P = 0.005). In addition, tissue copper concentration decreased as steatosis severity increased (P < 0.001). Copper levels were not associated with degree of fibrosis, lobular inflammation, portal inflammation, or balloon degeneration. CONCLUSIONS: In this cohort of pediatric subjects with NAFLD, we observed decreased tissue copper levels in subjects with NAFLD when compared with non-NAFLD subjects. In addition, tissue copper levels were lower in subjects with nonalcoholic steatohepatitis, a more severe form of the disease, when compared with steatosis alone. Further studies are needed to explore the relationship between copper levels and NAFLD progression.

Natural History of NAFLD Diagnosed in Childhood: A Single-Center Study.

Little is known regarding the subsequent course of non-alcoholic fatty liver disease (NAFLD) diagnosed in childhood. The objectives of this single-center study were to gather data on long-term health outcomes and to assess the feasibility of contacting former pediatric patients. In a large pediatric medical center, electronic records were searched to initially identify 162 former patients who had a liver biopsy between 2000 and 2010. Of these, 44 subjects met the criteria for age at follow-up (≥18 year) and biopsy-proven NAFLD, and were recruited via postal and electronic mail. Participants were invited to complete a brief telephone survey on current health status. Supplemental data was also obtained from pediatric medical charts of all subjects. At NAFLD diagnosis, 18% of subjects had diabetes, 91% were obese, 61% had NASH, and 56% had fibrosis on biopsy. At follow-up, 10 subjects (23%) responded to the survey. Based on the survey and chart review, after a mean follow-up of 4.5 years, 5 additional subjects developed diabetes for a period prevalence of 30%, and most subjects (78%) remained obese at last follow-up. Additional prospective studies are needed to fully describe the longitudinal risks associated with pediatric NAFLD, and will require multi-dimensional strategies to successfully recruit former patients.

Recipient-derived EBV-positive Monomorphic Plasmacytoma Type Posttransplant Lymphoproliferative Disorder After Allogeneic Stem Cell Transplant for Severe Aplastic Anemia: A Case Report.

Monomorphic plasmacytoma-type posttransplant lymphoproliferative disorder (PTLD) has not been reported after pediatric hematopoietic stem cell transplantation. We present a child with hepatitis-associated severe aplastic anemia who underwent an unrelated allogeneic hematopoietic stem cell transplantation and subsequently developed graft failure and an Epstein-Barr virus-positive monomorphic plasmacytoma-type PTLD of recipient origin. Despite broad-spectrum antimicrobials, weaning immunosuppression, rituximab administration, and a stem cell boost she died from complications of PTLD and a fungal pulmonary infection on day +78.

Congenital mesoblastic nephroma: a study of 19 cases using immunohistochemistry and ETV6-NTRK3 fusion gene rearrangement.

Mesoblastic nephroma (MN) is the most common renal tumour in the first 3 months of life and accounts for 3-5% of all paediatric renal neoplasms. To further understand the morphological variants of MN, we identified 19 cases of MN (five classic, eight cellular and six mixed) and examined each case for markers known to be important in urogenital embryological development (PAX8, WT1 and RCC), stem cell associated markers (Oct 4, CD34 and c-kit), muscle/myofibroblastic markers (muscle specific actin, calponin and h-caldesmon), aberrant transcription factors, cell cycle regulation and other oncogenic proteins (p16, cyclin D1 and beta-catenin). Fluorescence in situ hybridisation (FISH) testing for ETV6-NTRK3 gene fusion/rearrangement revealed further differentiation between the subtypes with ETV6-NTRK3 gene fusion detected in 0/5 of the classic MN, 8/8 of the cellular MN and 5/6 of the mixed MN cohorts, respectively. Our results conclude that cyclin D1 and beta-catenin may be useful markers for differentiating between cellular MN and classic MN when the histology is not conclusive. The absence of expression of stem cell markers and markers involved in urogenital development suggests that MN is not a nephroma and most likely represents a soft tissue tumour, with congenital infantile fibrosarcoma representing cellular MN with a predilection to arise in the kidney. In addition, the immunophenotype and genetic fingerprint of mixed MN most likely represents a heterogenous group of tumours that are mostly cellular type, with areas that are phenotypically less cellular.

Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D): Review of 16 Pediatric Cases and a Proposal of Modified Pediatric Criteria.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a heritable cardiomyopathy characterized by fibro-fatty replacement of right ventricular myocardium. Diagnostic criteria, established in 1994 and modified in 2010, are based on predominately adult manifestations of ARVC/D. The goal of this paper is to review a single-center experience with pediatric ARVC/D and propose modifications of current diagnostic criteria to appropriately include pediatric ARVC/D. We identified 16 pediatric cases of ARVC/D from our tertiary care center. Patient demographics, presentation, course, genetic testing, and family history were reviewed. Sixteen patients were diagnosed with ARVC/D through the modified diagnostic criteria, genetic testing, and pathology. Five patients had positive family histories. Five patients presented with cardiac arrest, and six were found to have ventricular tachycardia. Two patients presented with heart failure. Six autopsies, six explanted hearts, and three biopsies found massive fibro-fatty infiltration of the right ventricular wall. Six patients underwent heart transplantation, and two have received automatic implantable cardioverter defibrillator. Two patients had identifiable genetic mutations previously noted in the literature. One patient had a novel mutation of a known ARVC/D gene. Many pediatric patients do not meet the current ARVC/D diagnostic criteria, resulting in delays in diagnosis and treatment. The current criteria need further revision to encompass pediatric manifestations of ARVC/D. In our opinion, pathological and clinical findings alone are sufficient for accurate diagnosis of pediatric ARVC/D. Creating modified pediatric criteria would facilitate prompt diagnosis and management of ARVC/D and facilitate structured research with the goal of improving outcomes.

Rare presentation of four primary pediatric cardiac tumors.

Pediatric cardiac tumors are extremely rare and usually benign. We selected four unique cases of pediatric cardiac tumors from a 15-year period at our institution. The four chosen cases represent unique, rare primary tumors of the heart. Our selection includes a case of Rosai Dorfman disease without systemic involvement, which is, to our knowledge, the second case of isolated cardiac Rosai Dorfman disease in a child. We present a case of subtotal replacement of myocardium by granulocytic sarcoma with minimal bone marrow involvement, representing the first reported case in a child manifested as hypertrophic cardiomyopathy, as well as a case of a primary synovial sarcoma arising from the atrioventricular (AV) node, representing the fourth reported pediatric case of a cardiac synovial sarcoma, and it is the first to arise from the AV node. Finally, we present a primary congenital infantile fibrosarcoma of the heart, which is, to our knowledge, the first confirmed cardiac congenital infantile fibrosarcoma. These four cases represent the need for continued inclusion of rare cardiac conditions in a clinician's differential diagnosis. Furthermore, they present the need for more in-depth molecular and genomic analysis of pediatric cardiac tumors in order to identify their etiopathogenesis.

Identification of Bile Duct Paucity in Alagille Syndrome: Using CK7 and EMA Immunohistochemistry as a Reliable Panel for Accurate Diagnosis.

Bile duct paucity is the absence or marked reduction in the number of interlobular bile ducts (ILBD) within portal tracts. Its syndromic variant, Alagille syndrome (ALGS), is a multisystem disorder with effects on the liver, cardiovascular system, skeleton, face, and eyes. It is inherited as an autosomal dominant trait due to defects in NOTCH signaling pathway. ALGS is characterized by vanishing ILBD with subsequent chronic obstructive cholestasis in approximately 89% of cases. Cholestasis stimulates formation of new bile ductules through a process of neoductular reaction, making it difficult to evaluate the presence or absence of ILBD. Therefore, finding a method to differentiate clearly between ILBD and the ductular proliferation is essential for accurate diagnosis. A database search identified 28 patients with confirmed diagnosis of ALGS between 1992 and 2014. Additionally, 7 controls were used. A panel of two immunostains, cytokeratin 7 (CK7) and epithelial membrane antigen (EMA), was performed. CK7 highlighted the bile duct epithelium of ILBD and ductular proliferation, while EMA stained only the brush border of ILBD. In our ALGS group, the ratio of EMA-positive ILBD to identified portal tracts was 12.6% (range, 0%-41%). However, this same ratio was 95.0% (range, 90%-100%) among control cases (P < 0.001). We propose a panel of two immunostains, CK7 and EMA, to differentiate ILBD from ductular proliferation in patients with cholestasis. With this panel, identification of bile duct paucity can be achieved. Additional studies, including molecular confirmation and clinical correlation, would provide a definitive diagnosis of ALGS.

Atypical Marginal Zone Hyperplasia Is a Mimic for Lymphoma in Pediatric Transplant Recipients: Report of Two Patients.

Atypical marginal zone hyperplasia (AMZH) of mucosa-associated lymphoid tissue (MALT) closely resembles lymphoma in that it shows expansion of the marginal zones with prominent intraepithelial B lymphocytes, is immunoglobulin light-chain restricted, and may show aberrant CD43 expression. However, unlike lymphoma, it does not show rearrangement of the immunoglobulin heavy chain gene (immunoglobulin H [IgH]) by polymerase chain reaction (PCR), and it behaves in a benign fashion. We identified AMZH in 2 pediatric solid organ transplant recipients who presented with adenotonsillar hypertrophy. To date, the patients have experienced a self-limited course in the absence of treatment or reduction of immunosuppression. Atypical marginal zone hyperplasia is a pitfall for posttransplant lymphoproliferative disorder and MALT lymphoma in the pediatric solid organ transplant population. In transplant patients with a lambda-restricted B-cell clone and marginal zone hyperplasia in native MALT sites, PCR for IgH and IgK gene rearrangement is essential to prevent misdiagnosis.

Immunohistochemical Investigation of BRAF p.V600E mutations in thyroid carcinoma using 2 separate BRAF antibodies.

BACKGROUND: Approximately 45% of papillary thyroid carcinomas harbor BRAF p.V600E mutations and current practice algorithms endorse molecular testing for BRAF p.V600E. We assessed the utility of immunohistochemistry to detect BRAF p.V600E mutations in thyroid carcinomas using 2 separate BRAF monoclonal antibodies: one that detects both mutant and wild-type protein (pan-BRAF) and another that detects only the mutant protein (mut-BRAF). METHODS: We selected 41 formalin-fixed paraffin-embedded thyroid carcinomas (29 papillary, 1 follicular, 7 medullary, and 4 anaplastic) from 37 thyroidectomies and 4 fine-needle aspirations. Immunohistochemistry was performed using a pan-BRAF (clone EP152Y) or a mut-BRAF (clone VE1) monoclonal antibody. Tumors were considered positive if >10% of neoplastic cells showed moderate (2+) or strong (3+) cytoplasmic staining. BRAF p.V600E mutations were confirmed by molecular pyrosequencing, the gold standard for statistical analysis. RESULTS: pan-BRAF reactivity was observed in 80.5% (n=33) of cases: 34.1% (n=14) harbored BRAF p.V600E mutations and 46.3% (n=19) were wild type. mut-BRAF reactivity was observed in 46.3% (n=19) of cases: 34.1% (n=14) harbored BRAF p.V600E mutations and 12.2% (n=5) were wild type. The pan-BRAF antibody detected 14 more false positives (specificity: 29.6%, PPV: 42.4%) compared with the mut-BRAF antibody (specificity: 61.5%, PPV: 73.7%), but both antibodies detected the same 5 false positives. No false negatives were detected with either antibody (sensitivity and NPV 100.0% for both). CONCLUSIONS: The suboptimal specificity and PPV limits the diagnostic utility of both antibodies to reliably detect BRAF p.V600E mutations in thyroid carcinoma. However, both antibodies provide excellent sensitivity and NPV and either could be used to exclude BRAF wild-type thyroid carcinomas before molecular testing.

NOGO-A induction and localization during chick brain development indicate a role disparate from neurite outgrowth inhibition.

BACKGROUND: Nogo-A, a myelin-associated protein, inhibits neurite outgrowth and abates regeneration in the adult vertebrate central nervous system (CNS) and may play a role in maintaining neural pathways once established. However, the presence of Nogo-A during early CNS development is counterintuitive and hints at an additional role for Nogo-A beyond neurite inhibition. RESULTS: We isolated chicken NOGO-A and determined its sequence. A multiple alignment of the amino acid sequence across divergent species, identified five previously undescribed, Nogo-A specific conserved regions that may be relevant for development. NOGO gene transcripts (NOGO-A, NOGO-B and NOGO-C) were differentially expressed in the CNS during development and a second NOGO-A splice variant was identified. We further localized NOGO-A expression during key phases of CNS development by in situ hybridization. CNS-associated NOGO-A was induced coincident with neural plate formation and up-regulated by FGF in the transformation of non-neural ectoderm into neural precursors. NOGO-A expression was diffuse in the neuroectoderm during the early proliferative phase of development, and migration, but localized to large projection neurons of the optic tectum and tectal-associated nuclei during architectural differentiation, lamination and network establishment. CONCLUSION: These data suggest Nogo-A plays a functional role in the determination of neural identity and/or differentiation and also appears to play a later role in the networking of large projection neurons during neurite formation and synaptogenesis. These data indicate that Nogo-A is a multifunctional protein with additional roles during CNS development that are disparate from its later role of neurite outgrowth inhibition in the adult CNS.