Neurofibromatosis type 1

Vascular Abnormalities and Neurofibromatosis Type 1: A Paediatric Case Series

Neurofibromatosis type 1 (NF1) is a multisystemic neurocutaneous disease caused by a heterozygous mutation of the NF1 gene that encodes neurofibromin. Complications include vascular and neurologic abnormalities such as moyamoya syndrome, a cerebrovascular disorder with progressive occlusion of the large intracranial arteries, leading to ischemic events and the formation of abnormal vascular networks. Stenosis of the renal artery is another frequent complication of neurofibromatosis type 1, and it represents the most common cause of secondary hypertension in these patients. The purpose of the article is to describe the clinical manifestations of neurofibromatosis type 1 vasculopathy in 4 patients presenting with a wide range of neurologic and reno-vascular manifestations, as well as to examine current diagnostic management and follow-up, current therapeutic options, and to discuss further perspectives in terms of screening, diagnosis, and treatment.

Neurofibroma-like Desmoplastic Melanoma: A Series of Five Cases Exploring the Role of Molecular Testing as a Diagnostic Adjunct and Highlighting the Differential Diagnosis With Diffuse-type Neurofibroma

A subset of desmoplastic melanomas (DMs) can show extensive morphologic and immunohistochemical overlap with cutaneous diffuse-type neurofibroma. Neurofibroma-like desmoplastic melanoma (NFLDM) thus poses a significant diagnostic pitfall because the clinical implications of these 2 entities differ dramatically. A series of 17 DMs, including 5 cases of NFLDM, were compared with a cohort of 53 cutaneous diffuse-type neurofibromas to explore the utility of molecular testing in the differential diagnosis between NFLDM and neurofibroma and to determine potentially useful morphologic features in this differential diagnosis. Unlike NFLDM, cutaneous diffuse-type neurofibromas: (1) rarely feature intratumoral or peritumoral lymphoid aggregates, (2) consistently harbor an intrinsic stromal support vasculature composed of evenly spaced capillary-sized vessels, and (3) infiltrate adjacent adipose tissue in a dermatofibrosarcoma protuberans-like manner with a complete lack of chronic inflammation or fat necrosis at the leading edge of the tumor. Conversely, DMs, including NFLDM: (1) do not contain Wagner-Meissner bodies, (2) often induce fat necrosis and/or chronic inflammation at the interface with adjacent fibroadipose tissue, (3) lack the intrinsic capillary-sized stromal vasculature observed in most neurofibromas, and (4) may harbor foci of perineuriomatous differentiation, mimicking a hybrid nerve sheath tumor. Any deviation from the expected clinical or morphologic features of cutaneous diffuse-type neurofibroma should raise suspicion for NFLDM. Although not entirely sensitive or specific, molecular testing can help to support the diagnosis of NFLDM by demonstrating genetic abnormalities associated with melanoma, including a UV-light-induced mutational signature, high tumor mutational burden, and/or chromosomal copy number alterations typical of melanoma.

Mechanical properties of pediatric low-grade gliomas in children with and without neurofibromatosis type 1

INTRODUCTION

Prognoses for pediatric brain tumors are suboptimal, as even in low-grade tumors, management techniques can lead to damage in the developing brain. Therefore, advanced neuroimaging methods are critical for developing optimal management plans and improving patient care. Magnetic resonance elastography (MRE) has allowed for the characterization of adult gliomas by their mechanical properties, which are uniquely sensitive to the complex interplay of cellularity, vasculature, and interstitium. However, pediatric tumors differ in behavior and cytoarchitecture, and their mechanical properties have never been assessed.

METHODS

Here, we conduct the first study of pediatric brain tumor mechanical properties by using MRE to measure tissue stiffness and damping ratio in low grade gliomas (LGGs). We additionally measure the mechanical properties of non-neoplastic focal abnormal signal intensities (FASIs) in children with neurofibromatosis type 1 (NF1).

RESULTS

23 patients age 4-17 years who had MR imaging results consistent with a primary LGG or with NF1 were included in this study. We found that pediatric gliomas are on an average 10.9% softer (p = 0.010) with a 17.3% lower (p = 0.009) viscosity than reference tissue. Softness of tumors appeared consistent across tumor subtypes and unrelated to tumor size or contrast-enhancement. In NF1 we found that, unlike gliomas, FASIs are stiffer, though not significantly, than reference tissue by an average of 10.4% and have a 16.7% lower damping ratio.

CONCLUSIONS

Measuring tumor mechanical properties patterning and heterogeneity has potential to aid in prediction of biological behavior and inform management strategies for pediatric patients.

Neurofibromatosis type 1 - an update

Neurofibromatosis type 1 (NF1) is one of the most common genetic conditions. It can be inherited in an autosomal dominant manner, but almost half of cases occur de novo. NF1 is associated with café-au-lait macules, freckles in the inguinal and axillary region, neurofibromas, Lisch nodules of the iris or choroidal abnormalities, optic pathway gliomas, and distinctive bone anomalies. It has complete penetrance but highly variable disease manifestations. Certain features including café-au-lait macules, bony abnormalities, and optic pathway gliomas emerge by early childhood, but others appear later in life. A cure for NF1 has not been found, however emerging treatments have involved modulation of the RAS/MAPK signaling pathway.

Genotypes and phenotypes of neurofibromatosis type 1 patients in Japan: A Hereditary Tumor Cohort Study

Neurofibromatosis type 1 (NF1) presents with a broad spectrum of clinical manifestations, including an increased risk of tumor development and hypertension. Comprehensive data on genotype‒phenotype correlations in patients with NF1 are limited. Therefore, in this study, we aimed to elucidate the detailed genetic and clinical characteristics of NF1 in a hereditary tumor cohort. We performed sequencing and copy number assays in a clinical laboratory and analyzed the clinical data of 44 patients with suspected NF1. Germline pathogenic variants were detected in 36 patients (81.8%), and 20.7% of the variants were novel. Notably, 40.0% of adult patients presented with malignancies; female breast cancer occurred in 20.0% of patients, which was a higher rate than that previously reported. Hypertension was observed in 30.6% of the adult patients, with one patient experiencing sudden death and another developing pheochromocytoma. Three patients with large deletions in NF1 exhibited prominent cutaneous, skeletal, and neurological manifestations. These results highlight the importance of regular surveillance, particularly for patients with malignancies and hypertension. Our findings provide valuable insights for genetic counseling and clinical management, highlighting the multiple health risks associated with NF1 and the need for comprehensive and multidisciplinary care.

Adrenocortical tumors and hereditary syndromes

INTRODUCTION

Adrenocortical tumors (ACTs) are frequently encountered in clinical practice. They vary in clinical and biological characteristics from nonfunctional to life threatening hormone excess, from benign to highly aggressive malignant tumors. Most ACTs appear to be benign and nonfunctioning. It has been controversial how these apparently benign and nonfunctioning tumors should be monitored. Over the past few decades, significant advances have been made in understanding the regulation of growth and tumorigenesis in adrenocortical cells. Defining the molecular pathomechanisms in inherited tumor syndromes led to the expansion of research to sporadic ACTs. Distinct molecular signatures have been identified in sporadic ACTs and a potential genomic classification of ACT has been proposed.

AREAS COVERED

In this review, we discuss the various adrenocortical pathologies associated with hereditary syndromes with special focus on their molecular pathomechanisms, the understanding of which is important in the era of precision medicine.

EXPERT OPINION

Identifying the molecular pathomechanisms of the adrenocortical tumorigenesis in inherited syndromes has led to the understanding of the alterations in different signaling pathways that help explain the wide variations in the biology and behavior of ACTs.

Appendiceal neurofibroma after resection of multiple gastrointestinal stromal tumors of the small intestine in a patient with neurofibromatosis type 1: a case report

BACKGROUND

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is an autosomal dominant disorder that can affect multiple organs. Although gastrointestinal manifestations, such as neurofibromas and gastrointestinal stromal tumors (GISTs), can occur, appendiceal neurofibromas are extremely rare, with no documented cases of their occurrence following other gastrointestinal lesions. Herein, we report a case of an appendiceal neurofibroma following the resection of multiple small intestinal GISTs.

CASE PRESENTATION

A 68-year-old man with NF1 presented with melena and was diagnosed with anemia due to bleeding from multiple small intestinal GISTs. Laparoscopic three partial resection of the small intestine was performed to control the bleeding. Histopathologic examination revealed the proliferation of spindle cells that are positive for c-kit and Discovered on GIST-1, confirming the diagnosis of GIST. Two years later, a follow-up computed tomography (CT) scan revealed a progressively enlarging mass in the appendix with suspected invasion into the small intestine. Positron emission tomography/CT showed fludeoxyglucose accumulation in the tumor. Therefore, considering the possibility of malignancy, laparoscopic ileocecal resection with lymph node dissection was performed. Postoperatively, melena was observed, but the anemia did not progress and improved with fasting and hemostatic therapy. The patient was eventually discharged on postoperative day 8. Histopathologic examination revealed spindle cell proliferation with positivity for S-100, confirming the diagnosis of neurofibroma.

CONCLUSIONS

Patients with NF1 can develop a variety of gastrointestinal lesions. Appendiceal neurofibroma can be difficult to diagnose preoperatively and differentiate from malignancy. Hence, surgical resection should be considered.

Automatic construction of Petri net models for computational simulations of molecular interaction network

Petri nets are commonly applied in modeling biological systems. However, construction of a Petri net model for complex biological systems is often time consuming, and requires expertise in the research area, limiting their application. To address this challenge, we developed GINtoSPN, an R package that automates the conversion of multi-omics molecular interaction network extracted from the Global Integrative Network (GIN) into Petri nets in GraphML format. These GraphML files can be directly used for Signaling Petri Net (SPN) simulation. To demonstrate the utility of this tool, we built a Petri net model for neurofibromatosis type I. Simulation of NF1 gene knockout, compared to normal skin fibroblast cells, revealed persistent accumulation of Ras-GTPs as expected. Additionally, we identified several other genes substantially affected by the loss of NF1's function, exhibiting individual-specific variability. These results highlight the effectiveness of GINtoSPN in streamlining the modeling and simulation of complex biological systems.

ReNeu: A Pivotal, Phase IIb Trial of Mirdametinib in Adults and Children With Symptomatic Neurofibromatosis Type 1-Associated Plexiform Neurofibroma

PURPOSE

Pharmacologic therapies for neurofibromatosis type 1-associated plexiform neurofibromas (NF1-PNs) are limited; currently, none are US Food and Drug Administration-approved for adults.

METHODS

ReNeu is an open-label, multicenter, pivotal, phase IIb trial of mirdametinib in 58 adults (≥18 years of age) and 56 children (2 to 17 years of age) with NF1-PN causing significant morbidities. Patients received mirdametinib capsules or tablets for oral suspension (2 mg/m2 twice daily, maximum 4 mg twice daily), regardless of food intake, in 3 weeks on/1 week off 28-day cycles. The primary end point was confirmed objective response rate (ORR; proportion of patients with a ≥20% reduction of target PN volume from baseline on consecutive scans during the 24-cycle treatment phase) assessed by blinded independent central review (BICR) of volumetric magnetic resonance imaging.

RESULTS

Twenty-four of 58 adults (41%) and 29 of 56 children (52%) had a BICR-confirmed objective response during the 24-cycle treatment phase; in addition, two adults and one child had confirmed responses during long-term follow-up. Median (range) target PN volumetric best response was -41% (-90 to 13) in adults and -42% (-91 to 48) in children. Both cohorts reported significant and clinically meaningful improvement in patient- or parent proxy-reported outcome measures of worst tumor pain severity, pain interference, and health-related quality of life (HRQOL) that began early and were sustained during treatment. The most commonly reported treatment-related adverse events were dermatitis acneiform, diarrhea, and nausea in adults and dermatitis acneiform, diarrhea, and paronychia in children.

CONCLUSION

In ReNeu, the largest multicenter NF1-PN trial reported to date, mirdametinib treatment demonstrated significant confirmed ORRs by BICR, deep and durable PN volume reductions, and early, sustained, and clinically meaningful improvement in pain and HRQOL. Mirdametinib was well-tolerated in adults and children.

Developmental mosaicism underlying EGFR-mutant lung cancer presenting with multiple primary tumors

Although the development of multiple primary tumors in smokers with lung cancer can be attributed to carcinogen-induced field cancerization, the occurrence of multiple tumors at presentation in individuals with EGFR-mutant lung cancer who lack known environmental exposures remains unexplained. In the present study, we identified ten patients with early stage, resectable, non-small cell lung cancer who presented with multiple, anatomically distinct, EGFR-mutant tumors. We analyzed the phylogenetic relationships among multiple tumors from each patient using whole-exome sequencing (WES) and hypermutable poly(guanine) (poly(G)) repeat genotyping as orthogonal methods for lineage tracing. In four patients, developmental mosaicism, assessed by WES and poly(G) lineage tracing, indicates a common non-germline cell of origin. In two other patients, we identified germline EGFR variants, which confer moderately enhanced signaling when modeled in vitro. Thus, in addition to germline variants, developmental mosaicism defines a distinct mechanism of genetic predisposition to multiple EGFR-mutant primary tumors, with implications for their etiology and clinical management.

Effect of Everolimus on Prognosis of Neurofibromatosis Type 1 Lesions: A Systematic Review and Meta Analysis

PURPOSE

This study addresses the effectiveness of oral everolimus in treating various malignancies associated with Neurofibromatosis Type 1 (NF1). The purpose is to determine whether everolimus reduces lesion size in NF1 patients, considering the controversial findings from previous clinical trials. The scientific hypotheses and questions involve evaluating the impact of everolimus on NF1-associated lesions and understanding the variability in treatment outcomes.

METHODS

A systematic review and meta-analysis were conducted following PRISMA and Cochrane Collaboration guidelines. The study included four-phase II, single-arm, nonrandomized trials investigating the effect of oral everolimus on NF1-associated lesion size. The search covered multiple databases, and data extraction involved evaluating studies for inclusion criteria and assessing quality using the Cochrane Collaboration's Risk of Bias in Nonrandomized Studies tool. Statistical analysis utilized Open Meta(Analyst).

FINDINGS

The search yielded 388 studies, with 10 selected for full-text review and four included in the final analysis. The quality of the studies ranged from low to moderate. The meta-analysis indicated no observed heterogeneity (I^2 = 0%), and the overall estimate suggested no significant reduction in NF1-associated lesion size with everolimus (P = 0.069).

IMPLICATIONS

The findings reveal a varied and inconsistent picture of everolimus efficacy in NF1 treatment. The study highlights the need for personalized approaches, considering individual genetic and clinical differences. The limitations, including small sample sizes and nonrandomized trials, call for larger, more standardized research efforts. The study emphasizes ongoing trials and the importance of future research in understanding predictors of everolimus response and optimizing treatment strategies for NF1 patients.

CONCLUSION

While everolimus shows promise in reducing lesion size in a subset of NF1 patients, the study cannot draw conclusive results due to limitations in the included studies. Ongoing, adequately powered trials are crucial for advancing the evidence base and informing the potential role of everolimus in NF1 treatment.

OTHERS

There was no funding for this review and no conflicts of interest.

Stimulator of interferon gene facilitates recruitment of effector CD8 T cells that drive neurofibromatosis type 1 nerve tumor initiation and maintenance

Plexiform neurofibromas (PNFs) are benign nerve tumors driven by loss of the NF1 tumor suppressor in Schwann cells. PNFs are rich in immune cells, but whether immune cells are necessary for tumorigenesis is unknown. We show that inhibition of stimulator of interferon gene (STING) reduces plasma CXCL10, tumor T cell and dendritic cell (DC) recruitment, and tumor formation. Further, mice lacking XCR-1+ DCs showed reduced tumor-infiltrating T cells and PNF tumors. Antigen-presenting cells from tumor-bearing mice promoted CD8+ T cell proliferation in vitro, and PNF T cells expressed high levels of CCL5, implicating T cell activation. Notably, tumors and nerve-associated macrophages were absent in Rag1-/-; Nf1f/f; DhhCre mice and adoptive transfer of CD8+ T cells from tumor-bearing mice restored PNF initiation. In this setting, PNF shrunk upon subsequent T cell removal. Thus, STING pathway activation contributes to CD8+ T cell-dependent inflammatory responses required for PNF initiation and maintenance.

Proof of Concept for Genome Profiling of the Neurofibroma/Sarcoma Sequence in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder characterized by the predisposition to develop tumors such as malignant peripheral nerve sheath tumors (MPNSTs) which represents the primary cause of death for NF1-affected patients. Regardless of the high incidence and mortality, the molecular mechanisms underneath MPNST growth and metastatic progression remain poorly understood. In this proof-of-concept study, we performed somatic whole-exome sequencing (WES) to profile the genomic alterations in four samples from a patient with NF1-associated MPNST, consisting of a benign plexiform neurofibroma, a primary MPNST, and metastases from lung and skin tissues. By comparing genomic patterns, we identified a high level of variability across samples with distinctive genetic changes which allow for the definition of profiles of the early phase with respect to the late metastatic stages. Pathogenic and likely pathogenic variants were abundant in the primary tumor, whereas the metastatic samples exhibited a high level of copy-number variations (CNVs), highlighting a possible genomic instability in the late phases. The most known MPNST-related genes, such as TP53 and SUZ12, were identified in CNVs observed within the primary tumor. Pathway analysis of altered early genes in MPNST pointed to a potential role in cell motility, division and metabolism. Moreover, we employed survival analysis with the TCGA sarcoma genomic dataset on 262 affected patients, in order to corroborate the predictive significance of the identified early and metastatic MPNST driver genes. Specifically, the expression changes related to the mutated genes, such as in RBMX, PNPLA6 and AGAP2, were associated with reduced patient survival, distinguishing them as potential prognostic biomarkers. This study underlines the relevance of integrating genomic results with clinical information for early diagnosis and prognostic understanding of tumor aggressiveness.

Social Communication in Ras Pathway Disorders: A Comprehensive Review from Genetics to Behavior in Neurofibromatosis Type 1 and Noonan Syndrome

Neurofibromatosis type 1 (NF1) and Noonan syndrome (NS) are neurogenetic syndromes caused by pathogenetic variants encoding components of the Ras-ERK-MAPK signaling pathway (Ras pathway). NF1 and NS are associated with differences in social communication and related neuropsychiatric risks. During the last decade, there has been growing interest in Ras-linked syndromes as models to understand social communication deficits and autism spectrum disorders. We systematically review the literature between 2010-2023 focusing on the social communication construct of the RDoC framework. We provide an integrative summary of the research on facial and non-facial social communication processes in NF1 and NS across molecular, cellular, neural circuitry, and behavioral domains. At the molecular and cellular levels, dysregulation in the Ras pathway is intricately tied to variations in social communication through changes in GABAergic, glutamatergic, and serotonergic transmission, as well as inhibitory/excitatory imbalance. Neural circuitry typically associated with learning, attention, and memory in NF1 and NS (e.g., cortico-striatal connectivity), is also implicated in social communication. We highlight less researched, potential mechanisms for social communication, such as white matter connectivity and the default mode network. Finally, key gaps in NF1 and NS literature are identified and a roadmap for future research is provided. By leveraging genetic syndromes research, we can understand the mechanisms associated with behaviors and psychiatric disorders.

Managing neurofibromatosis type I and vision impairment in a resource-limited setting: a case study and multidisciplinary approach

Background

Neurofibromatosis type I (NF1) is a genetic disorder characterized by the development of multiple benign tumors along nerves in the skin, brain, and other parts of the body. It is associated with a range of clinical manifestations, including skin lesions, neurofibromas, and ocular abnormalities, which can significantly impact a patient's quality of life. Management of NF1 is particularly challenging in resource-limited settings due to limited access to diagnostic and therapeutic resources.

Clinical presentation

A 62-year-old woman with a known history of NF1 presented with progressive visual impairment. Her condition began in childhood with multiple hyperpigmented skin macules, which developed into numerous cutaneous tumors over time. Examination revealed numerous neurofibromas, café-au-lait spots, and axillary freckling. Significant visual impairment was caused by large fibromas on her eyelids. Histological analysis confirmed benign nerve tissue tumors.

Clinical discussion

The management strategy in this resource-limited setting focused on regular monitoring, patient education, symptomatic treatment, and multidisciplinary care. Despite the limitations, the patient's condition was managed effectively through these adapted strategies. The importance of genetic testing for confirmation and further management was noted but not performed due to resource constraints.

Conclusion

This case highlights the complexities of managing NF1 in resource-limited settings, emphasizing the need for adaptable management approaches. Multidisciplinary care and patient education were crucial in improving the patient's quality of life. This case underscores the importance of early diagnosis and intervention to prevent complications like visual impairment.

Spontaneous Tension Hemothorax in a Patient With Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is the most common phacomatosis. It is characterized by neurofibromas but also manifests vascular complications including stenosis, arterial ectasia, and aneurysms. We report the case of an otherwise healthy 45-year-old male who developed a fatal tension hemothorax due to bleeding from the left costocervical artery. Tension hemothorax without trauma is rare except in cases with a rupture of an aortic aneurysm; we successfully treated the patient by promptly diagnosing tension hemothorax and performing chest drainage, as well as timely transcatheter arterial embolization (TAE) to control bleeding. When encountering shock patients with NF1, clinicians should be mindful of the potential for non-traumatic hemorrhagic complications due to vascular malformation.

Written language achievement in children and adolescents with neurofibromatosis type 1 and Plexiform Neurofibromas

Neurofibromatosis type 1 (NF1) is associated with below average writing achievement. However, little is known about specific aspects of written language impacted by NF1, changes in writing over time, and associations between cognitive aspects of the NF1 phenotype and writing. At three timepoints over six years, children with NF1 and plexiform neurofibromas (PNs) completed Woodcock-Johnson tests of writing mechanics (Spelling, Punctuation & Capitalization, handwriting), written expression of ideas (Writing Samples), writing speed (Writing Fluency), and tests of general cognitive ability, executive function, memory, and attention. Children (N = 76, mean age = 12.8 ± 3.4 years) completed at least one baseline writing subtest. Overall writing scores were in the Average range (M = 93.4, SD = 17.4), but lower than population norms (p = 0.002). Scores were highest on Writing Samples (M = 95.2, SD = 17.3), and lowest for Punctuation & Capitalization (M = 87.9, SD = 18.8, p = 0.034). Writing scores were mostly stable over time. Nonverbal reasoning was related to some tests of writing mechanics and written expression of ideas. Short-term memory and inattention explained additional variance in Writing Samples and Spelling. Poor handwriting was associated with writing content beyond the impact of cognitive factors. Children with NF1 and PNs may benefit from early screening and writing support. Interventions should address the contribution of both cognitive and handwriting difficulties in written language.

Molecular markers for pediatric low-grade glioma

Over the past decade, our understanding of the molecular drivers of pediatric low-grade glioma (PLGG) has expanded dramatically. These tumors are predominantly driven by RAS/MAPK pathway activating alterations (fusions and point mutations), most frequently in BRAF, FGFR1, and NF1. Furthermore, additional second hits in tumor suppressor genes (TP53, ATRX, CDKN2A) can portend more aggressive behaviour. Accordingly, comprehensive molecular profiling-specifically genetic sequencing, often plus copy number profiling-has become critical for guiding the diagnosis and management of PLGG. In this review, we discuss the most important genetic alterations that inform on classification and prognosis of PLGG, highlighting their diagnostic and therapeutic relevance.

Current state of spinal nerve sheath tumor management and future advances

Nerve sheath tumors are the most common tumors of the spine after meningiomas. They include schwannomas, neurofibroma, and malignant peripheral nerve sheath tumors. These can arise sporadically or in association with tumor predisposition syndromes, including neurofibromatosis type 1, neurofibromatosis type 2, and schwannomatosis. Though surgery is the traditional mainstay of treatment for these tumors, the discovery of the genetic and molecular basis of these diseases in recent decades has prompted investigation into targeted therapies. Here, we give a clinical overview of spinal nerve sheath tumors, their imaging features, current management practices, and explore ongoing advances in systemic therapies.

Investigating therapeutic nonsense suppression in a neurofibromatosis mouse model

Neurofibromatosis type 1 (NF1) is a human genetic disorder caused by variants in the NF1 gene. Plexiform neurofibromas, one of many NF1 manifestations, are benign peripheral nerve sheath tumors occurring in up to 50% of NF1 patients. A substantial fraction of NF1 pathogenetic variants are nonsense mutations, which result in the synthesis of truncated non-functional NF1 protein (neurofibromin). To date, no therapeutics have restored neurofibromin expression or addressed the consequences of this protein's absence in NF1 nonsense mutation patients, but nonsense suppression is a potential approach to the problem. Ataluren is a small molecule drug that has been shown to stimulate functional nonsense codon readthrough in several models of nonsense mutation diseases, as well as in Duchenne muscular dystrophy patients. To test ataluren's potential applicability in nonsense mutation NF1 patients, we evaluated its therapeutic effects using three treatment regimens in a previously established NF1 patient-derived (c.2041C > T; p.Arg681X) nonsense mutation mouse model. Collectively, our experiments indicate that: i) ataluren appeared to slow the growth of neurofibromas and alleviate some paralysis phenotypes, ii) female Nf1-nonsense mutation mice manifested more severe paralysis and neurofibroma phenotypes than male mice, iii) ataluren doses with apparent effectiveness were lower in female mice than in male mice, and iv) age factors also influenced ataluren's effectiveness.

Anesthesia Management in Hereditary Pheochromocytoma and Paraganglioma: Updated Insights into Clinical Features and Perioperative Care

Approximately 40% of pheochromocytoma and paraganglioma (PPGL) cases are familial, typically presenting earlier with more complex symptoms. This paper synthesizes literature and guidelines to inform on clinical characteristics and perioperative care for PPGL. Pheochromocytoma in von Hippel-Lindau (VHL) disease exhibits heightened secretion activity without significant perioperative hemodynamic changes. Tumors in multiple endocrine neoplasia type 2 (MEN2) have a stronger endocrine function, which may induce hemodynamic fluctuations during surgery. Therefore, pheochromocytoma screening is essential at all stages of MEN2. Neurofibromatosis type 1 (NF1) often presents multisystem lesions and can result in difficult airway. Pheochromocytoma should be evaluated when NF1 patients present hypertension. Pheochromocytoma and paraganglioma type 5 may present multiple lesions of pheochromocytoma or paraganglioma. In summary, hereditary PPGLs may present with severe lesions in other systems, beyond tumor function. A multi-disciplinary team (MDT) approach is often invaluable in perioperative management.

The Multimodality Management of Malignant Peripheral Nerve Sheath Tumours

Malignant peripheral nerve sheath tumours (MPNST) are aggressive sarcomas that have nerve sheath differentiation and can present at any anatomical site. They can arise from precursor neurofibroma in the context of neurofibromatosis type 1 (NF1) or as de novo and sporadic tumours in the absence of an underlying genetic predisposition. The primary therapeutic approach is most often radical surgery, with non-surgical modalities playing an important role, especially in locally advanced or metastatic cases. The aim of multimodality approaches is to optimize both local and systemic control while keeping to a minimum acute and late treatment morbidity. Advances in the understanding of the underlying biology of MPNSTs in both sporadic and NF-1-related contexts are essential for the management and implementation of novel therapeutic approaches.

Periampullary duodenal neuroendocrine tumor in a patient with neurofibromatosis-1: A case report

BACKGROUND

Patients with neurofibromatosis type 1 (NF1) are exposed to a higher risk of developing neuroendocrine tumors (NETs). Periampullary neuroendocrine neoplasms (NENs) in NF1 patients primarily affect the duodenum and periampullary region.

CASE SUMMARY

A 50-year-old male patient was admitted to our hospital due to progressive skin and scleral yellowing for over 6 months. An abdominal contrast-enhanced computed tomography scan revealed a tumor in the periampullary region, which measured 1.2 cm × 1.4 cm in size and showed a progressive enhancement. Magnetic resonance cholangiopancreatography indicated the dilation of intrahepatic and extrahepatic bile ducts. The patient was diagnosed with an ampullary tumor with the possibility of malignancy. A Whipple procedure was performed. Microscopically, the duodenum tumor was found to invade the mucosa, sphincter, and muscular layer of the duodenal papilla. Histologic hematoxylin and eosin staining confirmed the presence of duodenal G1 NET. Subsequently, a bibliometric analysis was performed to evaluate the state of NEN research. Publications about periampullary NENs showed an annual increase, with most of them focusing on the treatment and diagnosis of NENs.

CONCLUSION

This article reported a case of periampullary duodenal NET in a patient with NF1, and a bibliometric analysis was conducted.

Hospital Visits Associated With Oral Infections in Patients With Neurofibromatosis Type 1: A Register-Based Analysis

Various forms of oral involvement have been reported in patients with neurofibromatosis 1 (NF1). Here, we analyze register-based associations between NF1 and hospital visits related to oral infections. The Finnish NF1 cohort encompasses all individuals with verified NF1 who have visited the Finnish central and university hospitals in 1987-2011. The Finnish Care Register for Health Care allowed the follow-up of 1349 individuals with NF1, their 1894 siblings without NF1, and 13,870 matched controls for diagnoses related to oral infections in 1998-2014. We observed clearly increased hazards for hospital visits associated with dental caries (ICD-10 K02; NF1 vs. controls, hazard ratio [HR] 4.42, 95% CI 3.23-6.04), diseases of pulp and periapical tissues (K04; HR 3.85, 95% CI 2.68-5.54), and gingivitis and periodontal diseases (K05; HR 3.63, 95% CI 2.37-5.56). In contrast, hospital visits related to diseases of salivary glands (K11), and stomatitis and related lesions (K12) did not show significantly increased hazard in NF1 compared with the controls or the non-NF1 siblings. In conclusion, the findings suggest that hospital visits related to oral infections are relatively common among individuals with NF1. The results highlight the need for early detection, proactive prevention, and timely treatment of oral infections in individuals with NF1.

The rare association of congenital glaucoma, giant melanocytic nevus, alopecia, and hypospadias in an Egyptian child with neurofibromatosis type 1: a case report

Background

Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder that commonly involves skin, nerves, and skeletal system with increased neoplastic predisposition. This disease has been rarely associated with multiple congenital anomalies. Herein, we describe an Egyptian child with NF1 and coexistent bilateral congenital glaucoma, giant congenital melanocytic nevi (GCMN), alopecia, and hypospadias.

Case presentation

A 2.5-year-old boy presented with developmental delay, back swelling, and multiple congenital anomalies. His father and two sisters were known to have NF1. The child was diagnosed with bilateral primary congenital glaucoma at the age of 3.5 months and underwent trabeculectomy with mitomycin C therapy. Examination at the age of 5 months revealed marked hypotonia, multiple GCMN, scanty café-au-lait macules, left upper eyelid plexiform neuroma and trichomegaly, hypertrichosis of left eyebrow, hypertelorism, depressed nasal bridge, left frontal scalp alopecia, and distal penile hypospadias. At the age of 8 months, brain imaging depicted a markedly dilated left lateral ventricle, and he underwent ventriculoperitoneal shunt surgery. The child developed back swelling at the age of 2.5 years, and a spinal magnetic resonance image showed bilateral multiple spinal neurofibromas in the paraspinal region with intraspinal extensions. A whole exome sequencing identified a heterozygous missense variant NM_001042492.3:c.1466A > G (NP_001035957.1:p.Tyr489Cys) in NF1 gene.

Conclusions

The present case report adds to the knowledge of the phenotypic spectrum and variability of NF1 by reporting the association of multiple unusual congenital anomalies. Importantly, such congenital anomalies could be the first presenting features in patients with NF1 since cafe´-au-lait macules and other typical diagnostic criteria may not be apparent in the neonatal period and early infancy. Accordingly, NF1 should be considered in newborns with congenital glaucoma, GCMN, scalp alopecia, and hypospadias.

Prenatal diagnosis for neurofibromatosis type 1 and the pitfalls of germline mosaics

We report our 5-year experience in neurofibromatosis type 1 prenatal diagnosis (PND): 205 PNDs in 146 women (chorionic villus biopsies, 88% or amniocentesis, 12%). The NF1 variant was present in 85 (41%) and absent in 122 (59%) fetuses. Among 205 pregnancies (207 fetuses), 135 were carried to term (119 unaffected and 16 NF1 affected children), 69 pregnancy terminations (affected fetuses), 2 miscarriages, and 1 in utero death. The majority of PND requests came from parents with sporadic NF1. We describe two PNDs in women with mosaic NF1. In both families, direct PND showed the absence of the maternal NF1 variant in the fetus. However, microsatellite markers analysis showed that the risk haplotype had been transmitted. These rare cases of germline mosaicism illustrate the pitfall of indirect PND. Our study illustrates the crucial consequences of PND for medical and genetic counseling decisions. We also point to the challenges of germline mosaics.

Inner retinal layer thickness alterations in adult and pediatric patients with neurofibromatosis 1

This study compared the thickness of each intraretinal layer in patients with neurofibromatosis 1 (NF1) and controls to analyze the association between intraretinal layer thickness and visual function. The macular spectral-domain optical coherence tomography volumetric dataset obtained from 68 eyes (25 adult eyes, 43 pediatric eyes) with NF1 without optic glioma and 143 control eyes (100 adult eyes, 43 pediatric eyes) was used for image auto-segmentation. The intraretinal layers segmented from the volumetric data included the macular retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), inner nuclear layer, outer plexiform layer, outer nuclear layer, and photoreceptor layer. Cases and controls were compared after adjusting for age, sex, refractive error, and binocular use. The association between retinal layer thickness and visual acuity was also analyzed. The GCIPL was significantly thinner in both adult and pediatric patients with NF1 compared with healthy controls. Average RNFL and GCIPL thicknesses were associated with visual acuity in adult patients with NF1. In pediatric patients, average GCIPL thickness was associated with visual acuity. These results suggest that changes in the inner retinal layer could be a biomarker of the structural and functional status of patients with NF1.

Treatment of giant neurofibromas in extremities and trunk wall of neurofibromatosis type 1 patients: a Chinese 12-year single-institution experience

BACKGROUNDS

Giant neurofibromas occurring in individuals diagnosed with neurofibromatosis type 1 (NF1) often result in considerable disfigurement, functional impairment, and diminished quality of life. Although debulking surgery poses inherent risks of complications, it remains the most efficacious approach to address these issues. The primary objective of this study was to share our surgical experience with giant neurofibromas in the extremities and trunk wall of NF1 patients which may help surgeons to minimize intraoperative bleeding and facilitate tumor excision.

METHODS

A retrospective review was conducted at a single center, encompassing 36 NF1 patients with giant neurofibromas in the extremities and trunk wall who underwent debulking surgery from July 2010 to July 2022.

RESULTS

Twenty-one male and fifteen female NF1 patients who received one to four surgical interventions were evaluated. The average age at the time of surgery was 17.8 years. The median follow-up time was 52 months. Our findings revealed relatively low rates of complications and recurrence. Notably, patients expressed satisfaction with both the aesthetic and functional results.

CONCLUSIONS

Debulking surgery of giant neurofibromas in the extremities and trunk wall of NF1 patients can effectively reduce the tumor burden, leading to improvements in both the appearance and function.

Ossification of neurofibroma in neurofibromatosis type 1, a case report of a rare presentation

INTRODUCTION

Although musculoskeletal involvement of Neurofibromatosis type 1 (NF1) has been well documented, bone formation, or ossification, within neurofibroma, has been scarcely documented in literature. Here, we report a rare case of ossified neurofibroma in a patient with long history of NF1.

PRESENTATION OF CASE

73-Year-old female with childhood-onset NF1 and surgical history of resection for multiple neurofibromas, presented with right ptosis and eyebrow ptosis. A growing tumor on the right eyebrow was surgically resected. Microscopically, the dermal tumor consists of bland spindle cells with thin, wavy nuclei, without atypia, showing S100 immunoreactivity, consistent with neurofibroma. Multiple metaplastic bone formation composed of mature bone trabeculae surrounding adipose tissue were apparent.

DISCUSSION

Up to date, ossification of neurofibroma has been scarcely reported in literature. The etiology is unclear but might involve the response to chronic stress and tissue damage over the years, and/or might indicate the potential differentiation plasticity of mesenchymal stem cell-like population.

CONCLUSION

The unusual presentation of ossification provides insights on the pathogenesis and differentiation plasticity of neurofibroma.

Unraveling neuronal and metabolic alterations in neurofibromatosis type 1

Neurofibromatosis type 1 (OMIM 162200) affects ~ 1 in 3,000 individuals worldwide and is one of the most common monogenetic neurogenetic disorders that impacts brain function. The disorder affects various organ systems, including the central nervous system, resulting in a spectrum of clinical manifestations. Significant progress has been made in understanding the disorder's pathophysiology, yet gaps persist in understanding how the complex signaling and systemic interactions affect the disorder. Two features of the disorder are alterations in neuronal function and metabolism, and emerging evidence suggests a potential relationship between them. This review summarizes neurofibromatosis type 1 features and recent research findings on disease mechanisms, with an emphasis on neuronal and metabolic features.

Long-term distress throughout one's life: health-related quality of life, economic and caregiver burden of patients with neurofibromatosis type 1 in China

Introduction

Neurofibromatosis type 1 (NF1) is a rare genetic disorder, with lack of evidence of disease burden in China. We aimed to describe the economic burden, health-related quality of life (HRQL), and caregiver burden of NF1 patients in China.

Methods

We conducted an online cross-sectional survey employing the China Cloud Platform for Rare Diseases, with 223 caregivers of NF1 pediatric patients (patients under 18), and 226 adult patients. Economic burden was estimated using direct and indirect costs related to NF1 in 2021, and the Work Productivity and Activity Impairment Questionnaire: General Health V2.0 (WPAI-GH). HRQL measures included EQ-5D-Y proxy version and PedsQL™ 4.0 Generic Core Scales (PedsQL GCS) proxy version for pediatric patients, and EQ-5D-5L and PedsQL™ 3.0 Neurofibromatosis Module (PedsQL NFM) for adult patients. Caregiver burden was estimated by Zarit Burden Interview (ZBI).

Results

For pediatric patients, the average direct cost in 2021 was CNY 33,614 (USD 4,879), and employed caregivers' annual productivity loss was 81 days. EQ-5D-Y utility was 0.880 ± 0.13 and VAS score was 75.38 ± 20.67, with 52.6% patients reporting having problems in "pain/discomfort" and 42.9% in "anxiety/depression." PedsQL GCS total score was 68.47 ± 19.42. ZBI score demonstrated that 39.5% of caregivers had moderate-to-severe or severe burden. For adult patients, average direct cost in 2021 was CNY 24,531 (USD 3,560). Patients in employment reported an absenteeism of 8.5% and presenteeism of 21.6% according to the results of WPAI-GH. EQ-5D-5L utility was 0.843 ± 0.17 and VAS score was 72.32 ± 23.49, with more than half of patients reporting having problems in "pain/discomfort" and "anxiety/depression" dimensions. PedsQL NFM total score was 68.40 ± 15.57.

Conclusion

Both pediatric and adult NF1 patients in China had a wide-ranging economic burden and low HRQL, especially in the psychological dimension. Caregivers for NF1 pediatric patients experienced considerable caregiver burden. More attention and support from policymakers and stakeholders are required to relieve NF1 patients' and caregivers' distress.

Efficient analysis of adverse drug events and toxicological mechanisms of newly marketed drugs by integrating pharmacovigilance and network toxicology: selumetinib as an example

Objective

To integrate pharmacovigilance and network toxicology methods to explore the potential adverse drug events (ADEs) and toxic mechanisms of selumetinib, and to provide a reference for quickly understanding the safety and toxicological mechanisms of newly marketed drugs.

Methods

Taking selumetinib as an example, this study integrated pharmacovigilance methods based on real-world data and network toxicology methods to analyze its ADE and its potential toxicological mechanism. First, the ADE reports of selumetinib were extracted from the US Food and Drug Administration (FDA) adverse event reporting system (FAERS), and the ADE signals were detected by reporting odds ratio (ROR) and UK medicines and healthcare products regulatory agency (MHRA) methods. The ADE signals were classified and described according to the preferred terms (PTs) and system organ class (SOC) derived from the Medical Dictionary for Regulatory Activities (MedDRA). The network toxicology method was used to analyze the toxicological mechanism of the interested SOCs. The specific steps included predicting the potential targets of selumetinib using TOXRIC, STITCH, ChEMBL, CTD, SwissTargetPreditcion, and Super-PRED databases, collecting the targets of SOC using GeneCards database, conducting protein-protein interaction (PPI) analysis through STRING database, conducting gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analysis through DAVID database, and testing the molecular affinity using AutoDock software.

Results

A total of 1388 ADE reports related to selumetinib were extracted, and 53 positive signals were detected by ROR and MHRA methods, of which 20 signals were not mentioned in the package insert, including ingrowing nail, hyperphosphatemia, cardiac valve disease, hematuria, neutropenia, etc. Analysis of the toxicological mechanism of six SOCs involved in positive ADE signals revealed that the key targets included EGFR, STAT3, AKT1, IL6, BCL2, etc., and the key pathways included PI3K/Akt pathway, apoptosis, ErbB signaling pathway, and EGFR tyrosine kinase inhibitor resistance, etc. Molecular docking assays showed spontaneous binding of selumetinib to key targets in these pathways.

Conclusion

The pharmacovigilance analysis identified some new potential ADEs of selumetinib, and the network toxicology analysis showed that the toxic effects of selumetinib may be related to PI3K/Akt pathway, apoptosis, ErbB signaling pathway, EGFR tyrosine kinase inhibitor resistance and other pathways.

The role of Clec11a in bone construction and remodeling

Bone is a dynamically active tissue whose health status is closely related to its construction and remodeling, and imbalances in bone homeostasis lead to a wide range of bone diseases. The sulfated glycoprotein C-type lectin structural domain family 11 member A (Clec11a) is a key factor in bone mass regulation that significantly promotes the osteogenic differentiation of bone marrow mesenchymal stem cells and osteoblasts and stimulates chondrocyte proliferation, thereby promoting longitudinal bone growth. More importantly, Clec11a has high therapeutic potential for treating various bone diseases and can enhance the therapeutic effects of the parathyroid hormone against osteoporosis. Clec11a is also involved in the stress/adaptive response of bone to exercise via mechanical stimulation of the cation channel Pieoz1. Clec11a plays an important role in promoting bone health and preventing bone disease and may represent a new target and novel drug for bone disease treatment. Therefore, this review aims to explore the role and possible mechanisms of Clec11a in the skeletal system, evaluate its value as a potential therapeutic target against bone diseases, and provide new ideas and strategies for basic research on Clec11a and preventing and treating bone disease.

Inhibition of autophagy as a novel treatment for neurofibromatosis type 1 tumors

Neurofibromatosis type 1 (NF1) is a genetic disorder caused by mutation of the NF1 gene that is associated with various symptoms, including the formation of benign tumors, called neurofibromas, within nerves. Drug treatments are currently limited. The mitogen-activated protein kinase kinase (MEK) inhibitor selumetinib is used for a subset of plexiform neurofibromas (PNs) but is not always effective and can cause side effects. Therefore, there is a clear need to discover new drugs to target NF1-deficient tumor cells. Using a Drosophila cell model of NF1, we performed synthetic lethal screens to identify novel drug targets. We identified 54 gene candidates, which were validated with variable dose analysis as a secondary screen. Pathways associated with five candidates could be targeted using existing drugs. Among these, chloroquine (CQ) and bafilomycin A1, known to target the autophagy pathway, showed the greatest potential for selectively killing NF1-deficient Drosophila cells. When further investigating autophagy-related genes, we found that 14 out of 30 genes tested had a synthetic lethal interaction with NF1. These 14 genes are involved in multiple aspects of the autophagy pathway and can be targeted with additional drugs that mediate the autophagy pathway, although CQ was the most effective. The lethal effect of autophagy inhibitors was conserved in a panel of human NF1-deficient Schwann cell lines, highlighting their translational potential. The effect of CQ was also conserved in a Drosophila NF1 in vivo model and in a xenografted NF1-deficient tumor cell line grown in mice, with CQ treatment resulting in a more significant reduction in tumor growth than selumetinib treatment. Furthermore, combined treatment with CQ and selumetinib resulted in a further reduction in NF1-deficient cell viability. In conclusion, NF1-deficient cells are vulnerable to disruption of the autophagy pathway. This pathway represents a promising target for the treatment of NF1-associated tumors, and we identified CQ as a candidate drug for the treatment of NF1 tumors.

A Fibroblast-Derived Secretome Stimulates the Growth and Invasiveness of 3D Plexiform Neurofibroma Spheroids

Plexiform neurofibromas (PNs) occur in about a half of neurofibromatosis type 1 (NF1) patients and have garnered significant research attention due to their capacity for growth and potential for malignant transformation. NF1 plexiform neurofibroma (pNF1) is a complex tumor composed of Schwann cell-derived tumor cells (Nf1-/-) and the tumor microenvironment (TME). Although it has been widely demonstrated that the TME is involved in the formation of neurofibromas, little is known about the effects of the TME on the subsequent progression of human pNF1. Elucidating the molecular interactions between tumor cells and the TME may provide new therapeutic targets to reduce the progression of pNF1. In the present study, we focused on the contributions of fibroblasts, the most abundant cell types in the TME, to the growth of pNF1. To simulate the TME, we used a three-dimensional (3D) coculture model of immortalized pNF1 tumor cells (Nf1-/-) and primary fibroblasts (Nf1+/-) derived from pNF1 patients. We performed live-cell imaging of 3D/4D (3D in real-time) cultures through confocal microscopy followed by 3D quantitative analyses using advanced imaging software. The growth of pNF1 spheroids in 3D cocultures with fibroblasts was significantly greater than that of pNF1 spheroids in 3D monocultures. An increase in the growth of pNF1 spheroids also occurred when they were cultured with conditioned media (CM) from fibroblasts. Moreover, fibroblast-derived CM increased the invasive outgrowth and further local invasion of pNF1 spheroids. Interestingly, when small extracellular vesicles (sEVs) were depleted from the fibroblast-derived CM, the stimulation of the growth of pNF1 spheroids was lost. Our results suggest that fibroblast-derived sEVs are a therapeutic target for reducing the growth of pNF1.

A Comprehensive Overview of NF1 Mutations in Iranian Patients

Neurofibromatosis type 1 (NF1) is a genetic disorder caused by mutations in the NF1 gene. This disorder shows nearly complete penetrance and high phenotypic variability. We used the whole-exome sequencing technique to identify mutations in 32 NF1 cases from 22 Iranian families. A total of 31 variants, including 30 point mutations and one large deletion, were detected. In eight cases, variants were inherited, while they were sporadic in the remaining. Seven novel variants, including c.5576 T > G, c.6658_6659insC, c.2322dupT, c.92_93insAA, c.4360C > T, c.3814C > T, and c.4565_4566delinsC, were identified. The current study is the largest in terms of the sample size of Iranian NF1 cases with identified mutations. The results can broaden the spectrum of NF1 mutations and facilitate the process of genetic counseling in the affected families.

A case of malignant pheochromocytoma with neurofibromatosis type 1 having difficulty in differentiating spinal tumor

Introduction

Neurofibromatosis type 1 is a hereditary condition often associated with pheochromocytomas but rarely with malignant pheochromocytomas. Neurofibromatosis type 1 is often associated with bone lesions, which complicates the distinction between malignant and benign tumors.

Case presentation

A 46-year-old man with a medical history of neurofibromatosis type 1 presented with right abdominal pain. Computed tomography revealed a right adrenal tumor, and metaiodobenzylguanidine scintigraphy showed accumulation in the right adrenal gland and thoracic vertebrae. He was diagnosed with pheochromocytoma, and a right adrenalectomy was performed. After surgery, a bone biopsy was conducted on the spinal lesion, confirming metastasis of pheochromocytoma, prompting irradiation. After that, lung and liver metastases emerged, and chemotherapy with cyclophosphamide, vincristine, and dacarbazine was initiated; however, the disease progressed, and he died 11 months after surgery.

Conclusion

We report a case of malignant pheochromocytoma associated with neurofibromatosis type 1 in which bone metastasis was difficult to diagnose.

Clinical features and surgical treatments of scoliosis in neurofibromatosis type 1: a systemic review and meta-analysis

BACKGROUND

Neurofibromatosis type 1 (NF 1) is an autosomal-dominant tumor predisposition genetic disease affecting approximately 1 in 3000 live births. The condition could present various manifestations ranging from skin abnormalities to neurological tumors. The musculoskeletal system could also be frequently affected, and scoliosis is the most common orthopedic manifestation. Characterized by the early-onset and rapid progression tendency, NF 1-related dystrophic scoliosis presented discrepancies from idiopathic scoliosis in terms of natural history, clinical features, and management outcomes and thus required special attention. In the current study, the authors conducted a systemic review to outline the body of evidence of the natural history, clinical characteristics, surgical outcomes, and surgical complications of NF 1-induced scoliosis, aiming to provide an elucidative insight into this condition.

METHOD

Systemic review and meta-analysis were conducted according to the latest Preferred Reporting Items for Systematic Reviews Meta-Analyses (PRISMA) guidelines. The search was performed in Medline, Embase, and Web of Science Core Collection up to December 27, 2022, using related keywords. Clinical features such as frequencies, segmental involvement, and hereditary information were summarized and described qualitatively. Meta-analysis was conducted using R software and the 'meta' package to yield an overall outcome of efficacy and safety of surgical management, precisely, spinal fusion procedure and growing rods procedure. Corrective rate of Cobb angle, sagittal kyphosis angle, and T1-S1 length post-operative and at the last follow-up was used to evaluate the efficacy, and the occurrence of surgery-related complications was used to evaluate the safety.

RESULT

A total of 37 articles involving 1023 patients were included. Approximately 26.6% of the NF 1 patients would present with scoliosis. Patients tend to develop scoliosis at an earlier age. The thoracic part turned out to be the most affected segment. No obvious correlation between scoliosis and genotype or hereditary type was observed. Both spinal fusion and growing rod surgery have shown acceptable treatment outcomes, with spinal fusion demonstrating better performance in terms of effectiveness and safety. The growing rods technique seemed to allow a better lengthening of the spine. The mainstay post-operative complications were implant-related complications but could be managed with limited revision surgery. Severe neurological deficits were rarely reported.

CONCLUSION

Scoliosis, especially the subtype characterized by dystrophic bony changes, is a significant orthopedic manifestation of NF1. It has an early onset, a tendency to persistently and rapidly progress, and is challenging to deal with. The current review outlines the available evidence from the perspective of natural history, clinical features, and the treatment efficacy and safety of the mainstay surgical options. Patients with NF1 scoliosis will benefit from a better understanding of the disease and evidence based treatment strategies.

Association of sociodemographic and clinical factors with the quality of life of Brazilian individuals with Neurofibromatosis type 1: a cross-sectional study

BACKGROUND

Neurofibromatosis type 1 (NF1) is a rare genetic disorder with a wide range of clinical manifestations, notably neurocutaneous features, that can lead to emotional and physical consequences.

OBJECTIVES

This study assessed the influence of sociodemographic factors and clinical features of the disease on the quality of life of Brazilian individuals with NF1.

METHODS

This is a descriptive cross-sectional study. Data were collected from 101 individuals with NF1 using the Brazilian version of the Impact of NF1 on Quality of Life Questionnaire (INF1-QoL), a form with information on sociodemographic characteristics, and an NF1 visibility self-evaluation scale. The relationship between variables was evaluated through statistical testing, and the significance level was defined as 0.05.

RESULTS

The study included 101 adults with NF1 aged 18 to 59 years, with a mean age of 35.54 years (±9.63) and a female predominance (n = 84, 83.17%). The mean total INF1-QoL score was 10.62 (±5.63), with a median of 10, minimum value of 0, and maximum of 31 points. Two characteristics of the participants were significantly associated with the quality of life: educational level (p = 0.003) and familial history of NF1 (p = 0.019). There was a statistically significant correlation between the INF1-QoL score and the degree of disease visibility (rho = 0.218; p = 0.028).

STUDY LIMITATIONS

Cross-sectional study, conducted with a convenience sample and using self-reported measures.

CONCLUSIONS

The findings support the significant impact of NF1 on quality of life. The authors recommend multidisciplinary follow-up for patients, with adherence to anticipatory clinical care measures, adequate pain control, psychological assistance, and genetic counseling.

MEK-SHP2 inhibition prevents tibial pseudarthrosis caused by NF1 loss in Schwann cells and skeletal stem/progenitor cells

Congenital pseudarthrosis of the tibia (CPT) is a severe pathology marked by spontaneous bone fractures that fail to heal, leading to fibrous nonunion. Half of patients with CPT are affected by the multisystemic genetic disorder neurofibromatosis type 1 (NF1) caused by mutations in the NF1 tumor suppressor gene, a negative regulator of RAS-mitogen-activated protein kinase (MAPK) signaling pathway. Here, we analyzed patients with CPT and Prss56-Nf1 knockout mice to elucidate the pathogenic mechanisms of CPT-related fibrous nonunion and explored a pharmacological approach to treat CPT. We identified NF1-deficient Schwann cells and skeletal stem/progenitor cells (SSPCs) in pathological periosteum as affected cell types driving fibrosis. Whereas NF1-deficient SSPCs adopted a fibrotic fate, NF1-deficient Schwann cells produced critical paracrine factors including transforming growth factor-β and induced fibrotic differentiation of wild-type SSPCs. To counteract the elevated RAS-MAPK signaling in both NF1-deficient Schwann cells and SSPCs, we used MAPK kinase (MEK) and Src homology 2 containing protein tyrosine phosphatase 2 (SHP2) inhibitors. Combined MEK-SHP2 inhibition in vivo prevented fibrous nonunion in the Prss56-Nf1 knockout mouse model, providing a promising therapeutic strategy for the treatment of fibrous nonunion in CPT.

Revisiting the NPcis mouse model: A new tool to model plexiform neurofibroma

Neurofibromatosis Type I (NF1) is a rare genetic disorder. NF1 patients frequently develop a benign tumor in peripheral nerve plexuses called plexiform neurofibroma. In the past two decades, tissue-specific Nf1 knockout mouse models were developed using commercially available tissue-specific Cre recombinase and the Nf1 flox mice to mimic neurofibroma development. However, these models develop para-spinal neurofibroma, recapitulating a rare type of neurofibroma found in NF1 patients. The NPcis mouse model developed a malignant version of neurofibroma called malignant peripheral nerve sheath tumor (MPNST) within 3 to 6 months but intriguingly without apparent benign precursor lesion. Here, we revisited the NPcis model and discovered that about 20% display clinical signs similar to Nf1 tissue-specific knockout mice models. However, a systematic histological analysis could not explain the clinical signs we observed although we noticed lesions reminiscent of a neurofibroma in a peripheral nerve, a cutaneous neurofibroma, and para-spinal neurofibroma on rare occasions in NPcis mice. We also observed that 10% of the mice developed a malignant peripheral nerve sheath tumor (MPNST) spontaneously, coinciding with their earring tag identification. Strikingly, half of the sciatic nerves from NPcis mice developed plexiform neurofibroma within 1-6 months when intentionally injured. Thus, we provided a procedure to turn the widely used NPcis sarcoma model into a model recapitulating plexiform neurofibroma.

Perceived transition readiness among adolescents and young adults with neurofibromatosis type 1 and plexiform neurofibromas: a cross-sectional descriptive study

OBJECTIVES

Neurofibromatosis type 1 (NF1) is a genetic cancer predisposition syndrome that can impact multiple organ systems and is associated with plexiform neurofibroma tumors, requiring care from birth through adulthood. Adolescents and young adults (AYAs) with NF1 face several barriers to transition from pediatric to adult care. This cross-sectional study aimed to assess transition readiness in this population and to evaluate relationships between specific NF1 symptoms and transition readiness.

METHODS

AYAs (aged 16-24) enrolled in existing studies related to NF1 were eligible. AYAs and their parents completed measures of transition readiness (Transition Readiness Assessment Questionnaire version 4 [TRAQ-4]), and AYAs also completed a transition readiness interview (UNC TRxANSITION).

RESULTS

Thirty-eight AYAs (mean age = 19.95 ± 2.68 years) participated in the study. Average TRAQ scores indicated that AYAs were still learning Self-Management skills (M = 3.37, SD = 1.08) and Self-Advocacy skills (M = 3.98, SD = 0.67). Older AYAs had higher TRAQ scores for Self-Management (r = 0.70, p < .001) and Self-Advocacy (r = 0.41, p = .011) than younger AYAs. Parents and AYAs had similar TRAQ scores. About one third of AYAs (37.8%, n = 14) expressed uncertainty about how NF1 might affect them in the future. The remaining AYAs mostly expressed concerns regarding tumor growth, pain, or cancer.

CONCLUSIONS

In this small study, preliminary findings suggest that AYAs with NF1 express confidence in many areas of transition readiness but continue to require support, particularly with Self-Management skills. Given the gaps in understanding of future health risks, AYAs with NF1 would benefit from early assessment, psychoeducation, and support for transition readiness to adult care.

Generation of a human iPSC line CIPi004-A from a patient with neurofibromatosis type 1 and epilepsy harboring a heterozygous mutation in NF1 gene

The NF1 gene is related to neurofibromatosis type 1 (NF1), which is an autosomal dominant disorder associated with multisystem involvement and epilepsy susceptibility. A human induced pluripotent stem cell (iPSC) line was derived from a pediatric patient with NF1 and epilepsy, harboring a heterozygous NF1 gene mutation. The iPSC line exhibits high levels of pluripotency markers, maintains the NF1 gene mutation, and demonstrates the capacity to undergo differentiation potential in vitro into three germ layers. The iPSC line will serve as a valuable resource for investigating the underlying mechanisms and conducting drug screening related to NF1 and NF1-associated epilepsy.

Contemporary Approach to Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors

Most malignant peripheral nerve sheath tumors (MPNSTs) are clinically aggressive high-grade sarcomas, arising in individuals with neurofibromatosis type 1 (NF1) at a significantly elevated estimated lifetime frequency of 8%-13%. In the setting of NF1, MPNSTs arise from malignant transformation of benign plexiform neurofibroma and borderline atypical neurofibromas. Composed of neoplastic cells from the Schwannian lineage, these cancers recur in approximately 50% of individuals, and most patients die within five years of diagnosis, despite surgical resection, radiation, and chemotherapy. Treatment for metastatic disease is limited to cytotoxic chemotherapy and investigational clinical trials. In this article, we review the pathophysiology of this aggressive cancer and current approaches to surveillance and treatment.

Advances in pediatric gliomas: from molecular characterization to personalized treatments

Pediatric gliomas, consisting of both pediatric low-grade (pLGG) and high-grade gliomas (pHGG), are the most frequently occurring brain tumors in children. Over the last decade, several milestone advancements in treatments have been achieved as a result of stronger understanding of the molecular biology behind these tumors. This review provides an overview of pLGG and pHGG highlighting their clinical presentation, molecular characteristics, and latest advancements in therapeutic treatments.  Conclusion: The increasing understanding of the molecular biology characterizing pediatric low and high grade gliomas has revolutionized treatment options for these patients, especially in pLGG. The implementation of next generation sequencing techniques for these tumors is crucial in obtaining less toxic and more efficacious treatments. What is Known: • Pediatric Gliomas are the most common brain tumour in children. They are responsible for significant morbidity and mortality in this population. What is New: • Over the last two decades, there has been a significant increase in our global understanding of the molecular background of pediatric low and high grade gliomas. • The implementation of next generation sequencing techniques for these tumors is crucial in obtaining less toxic and more efficacious treatments, with the ultimate goal of improving both the survival and the quality of life of these patients.

Incidence of tethered cord syndrome in neurofibromatosis types 1 and 2 pediatric patients: a population-level analysis

PURPOSE

Tethered spinal cord syndrome (TCS) is characterized by cutaneous attachments on the filum terminale that stretch the spinal cord, leading to musculoskeletal and urogenital sequelae. While the neurocutaneous associations with TCS remain undefined, a recent study reports a high incidence of TCS among a pediatric neurofibromatosis (NF) cohort. This present study utilizes a population-level database to estimate TCS incidence among pediatric patients with neurofibromatosis types 1 and 2 (NF1, NF2).

METHODS

The TriNetX Research Network was queried to identify patients diagnosed with NF and/or TCS before the age of 21. Symptomatic TCS requiring surgical intervention was identified using corresponding procedural codes within 12 months following TCS diagnosis. Odds ratios (OR) were calculated to measure the associations of NF1/NF2 with TCS.

RESULTS

19,426 pediatric NF patients were evaluated (NF1: 18,383, NF2: 1042). The average ages of TCS diagnosis among NF1, NF2, and non-NF patients were 12, 16, and 9 years, respectively. The incidence of TCS was 1.2% in NF1 patients and 7.3% in NF2 patients, compared to 0.074% in the general population. The associations of NF incidence with TCS were significantly increased in both NF1 (OR 16.42; 14.38-18.76) and NF2 (OR 105.58; 83.56-133.40) patients compared to the general population. Symptomatic TCS requiring surgical intervention was not significantly associated with NF1/NF2 patients compared to the general TCS population.

CONCLUSION

This analysis demonstrates a high incidence of TCS but delayed intervention in pediatric NF patients. Considering TCS counseling, spinal MRI, and earlier intervention may be warranted for NF patients experiencing musculoskeletal symptomatology.