Revised diagnostic criteria for neurofibromatosis type 1 and Legius syndrome: an international consensus recommendation

Total Knee Arthroplasty in a Patient With Neurofibromatosis 1

Neurofibromatosis 1 (NF1) is a rare genetic syndrome that leads to the development of neurofibromas and increases the risk of malignancy, including malignant peripheral nerve sheath tumors. Patients with NF1 often have other orthopaedic manifestations, including short stature, osteopenia, and dysplasia. A 47-year-old patient with a history of NF1 and multiple neurofibromas of the right lower extremity presented with a severe valgus deformity, instability, and osteoarthritis of the right knee that was debilitating to daily life. Over time, the patient lost proprioception and potentially some sensation to the right knee with neurofibroma formation, leading to the development of Charcot arthropathy of the right knee with secondary osteoarthritis. The preoperative workup consisted of a magnetic resonance imaging of the knee to confirm no malignancy was present and templating to ensure the standard implant size was amenable for the patient. A primary total knee arthroplasty was performed with a cemented-stemmed hinged knee implant. At 6 months post-surgery, the patient had a dramatic improvement in her pain and quality of life.

Incidence of Hearing Loss in Patients With Neurofibromatosis Type 1 at a Tertiary Care Pediatric Hospital

BACKGROUND

Hearing loss has not been thoroughly investigated as a comorbidity in larger cohorts with neurofibromatosis type 1 (NF1).

METHODS

Available audiometric data were reviewed from patients with NF1 seen at a tertiary pediatric hospital to assess prevalence and risk factors for hearing loss.

RESULTS

Of 1172 patients with NF1 seen between 2010 and 2022, 90 had available audiometric data and 48 of 90 patients (53%) had one or more audiogram revealing hearing loss. Those not referred to audiology were presumed to have normal hearing, resulting in a conservative hearing loss estimate of 4% for children and young adults with NF1. Of 90 patients with audiograms, 29 (32%) had conductive loss (CHL), 15 (17%) had sensorineural loss (SNHL), and 3 (3%) had mixed hearing loss. Hearing loss type was undetermined for one patient. For children with CHL, six had permanent CHL secondary to plexiform neurofibroma, 19 CHL were transient due to active middle ear dysfunction, and four CHL cases were indeterminate in etiology. For three children with SNHL or mixed hearing loss, etiology included history of ototoxic chemotherapy and/or family history of SNHL. In the 16 patients with SNHL or mixed hearing loss with more than one audiogram over time, progressive hearing decline was noted in eight of 16, and 26 of 178 hearing thresholds (15%) progressed.

CONCLUSIONS

Our findings suggest that audiometric evaluations should be considered for at least a subset of children with NF1, given the higher-than-expected rate of hearing loss in patients with NF1 compared with the general population.

Different de novo mutations in the NF1 gene in a family with neurofibromatosis type 1

The criteria for clinical diagnosis of neurofibromatosis type 1 (NF1) are not sensitive in young children. Recognition is easier when one of their parents has been diagnosed with this condition, and the causal mutation is known. We present a case of a girl with isolated café-au-lait spots, whose father was diagnosed with NF1. However, both were found to carry different de novo mutations in the NF1 gene. This possibility has significant implications for the diagnostic process and genetic counseling.

Comparing 3D imaging devices for the measurement of cutaneous neurofibromas in patients with Neurofibromatosis Type 1

BACKGROUND

Cutaneous neurofibromas (cNFs) are a major cause of disfigurement in patients with Neurofibromatosis Type 1 (NF1). However, clinical trials investigating cNF treatments lack standardised outcome measures to objectively evaluate changes in cNF size and appearance. 3D imaging has been proposed as an objective standardised outcome measure however various systems exist with different features that affect useability in clinical settings. The aim of this study was to compare the accuracy, precision, feasibility, reliability and accessibility of three imaging systems.

MATERIALS AND METHODS

We compared the Vectra-H1, LifeViz-Micro and Cherry-Imaging systems. A total of 58 cNFs from 13 participants with NF1 were selected for imaging and analysis. The primary endpoint was accuracy as measured by comparison of measurements between imaging systems. Secondary endpoints included reliability between two operators, precision as measured with the average coefficient of variation, feasibility as determined by time to capture and analyse an image and accessibility as determined by cost.

RESULTS

There was no significant difference in accuracy between the three devices for length or surface area measurements (p > 0.05), and reliability and precision were similar. Volume measurements demonstrated the most variability compared to other measurements; LifeViz-Micro demonstrated the least measurement variability for surface area and image capture and analysis were fastest with LifeViz-Micro. LifeViz-Micro was better for imaging smaller number of cNFs (1-3), Vectra-H1 better for larger areas and Cherry for uneven surfaces.

CONCLUSIONS

All systems demonstrated excellent reliability but possess distinct advantages and limitations. Surface area is the most consistent and reliable parameter for measuring cNF size in clinical trials.

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.

PRAP study-partial versus radical adrenalectomy in hereditary pheochromocytomas

OBJECTIVE

Hereditary pheochromocytoma (hPCC) commonly develops bilaterally, causing adrenal insufficiency when standard treatment, radical adrenalectomy (RA), is performed. Partial adrenalectomy (PA) aims to preserve adrenal function, but with higher recurrence rates. This study compares outcomes of PA versus RA in hPCC.

METHODS

Patients with hPCC due to pathogenic variants in RET, VHL, NF1, MAX, and TMEM127 from 12 European centers (1974-2023) were studied retrospectively. Stratified analysis based on surgery type and initial presentation was conducted. The main outcomes included recurrence, adrenal insufficiency, metastasis, and mortality.

RESULTS

The study included 256 patients (223 RA, 33 PA). Ipsilateral recurrence rates were 9/223 (4%) after RA versus 5/33 (15%) after PA (P = 0.02). Metastasis and mortality did not differ between groups. Overall, 103 patients (40%) underwent bilateral adrenalectomy either synchronously or metachronously (75 RA, 28 PA). Of these, 46% developed adrenal insufficiency after PA.In total, 191 patients presented with initial unilateral disease, of whom 50 (26%) developed metachronous contralateral disease, most commonly in RET, VHL, and MAX. In patients with metachronous bilateral disease, adrenal insufficiency developed in 3/4 (75%) when PA was performed as the first operation followed by RA, compared to 1/7 (14%) when PA was performed as the second operation after prior RA (P = 0.09).

CONCLUSION

In patients with hPCC undergoing PA, local recurrence rates are higher than after RA, but metastasis and disease-specific mortality are similar. Therefore, PA seems a safe method to preserve adrenal function in patients with hPCC, in cases of both synchronous and metachronous bilateral disease, when performed as a second operation.

Encephalocraniocutaneous lipomatosis phenotype associated with mosaic biallelic pathogenic variants in the NF1 gene

Encephalocraniocutaneous lipomatosis (ECCL) is a sporadic congenital condition characterised by ocular, cutaneous and central nervous system involvement. Mosaic activating variants in FGFR1 and KRAS have been reported in several individuals with this syndrome. We report on a patient with neurofibromatosis type 1 (NF1) with a germline pathogenic variant in the NF1 gene and an ECCL phenotype, suggesting ECCL to be part of a spectrum of malformations associated with NF1 pathogenic variants. An anatomical hemispherectomy was performed for intractable epilepsy. Through genetic analysis of blood, cerebral tissue and giant cell lesions in both jaws, we identified the germline NF1 pathogenic variant in all samples and a second-hit pathogenic NF1 variant in cerebral tissue and both giant cell lesions. Both NF1 variants were located on different alleles resulting in somatic mosaicism for a biallelic NF1 inactivation originating in early embryogenesis (second-hit mosaicism or Happle type 2 mosaicism). The biallelic deficit in NF1 in the left hemicranium explains the severe localised, congenital abnormality in this patient. Identical first and second-hit variants in a giant cell lesion of both upper and lower jaws provide confirmatory evidence for an early embryonic second hit involving at least the neural crest. We suggest that the ECCL phenotype may be part of a spectrum of congenital problems associated with mosaic NF1 nullisomy originating during early embryogenesis. The biallelic NF1 inactivation during early embryogenesis mimics the severe activation of the RAS-MAPK pathway seen in ECCL caused by embryonic mosaic activating FGFR1 and KRAS variants in the cranial region. We propose that distinct mechanisms of mosaicism can cause the ECCL phenotype through convergence on the RAS-MAPK pathway.

Cutaneous Neurofibromas and Quality of Life in Adults With Neurofibromatosis Type 1

Importance

There is a burgeoning interest in therapeutic development for cutaneous neurofibromas (cNFs), a major cause of morbidity in persons with neurofibromatosis type 1 (NF1). To determine meaningful clinical trial outcomes, deeper understanding is needed regarding how cNFs are associated with quality of life (QoL). However, this understanding has been hampered by challenges in recruiting participants with this rare genetic disease.

Objective

To develop a large, crowdsourced validated registry of persons with NF1 and determine the association of specific cNF features with QoL, pain, and itch.

Design, Setting, and Participants

From May 2021 to December 2023, a decentralized platform was developed and recruited persons 40 years or older with NF1 and at least 1 cNF from 49 states and 12 countries, who provided clinical survey data, detailed photographs, and genetic sequencing data. Photographs from 583 participants were scored on 12 features of cNFs, including general severity, number, size, facial severity, color, and subtypes.

Exposure

cNF features derived from participant-supplied photographs.

Main Outcomes and Measures

Total Skindex scores and subdomain scores (symptoms, emotion, function, pain, and itch).

Results

Of 583 participants, 384 (65.9%) were female, and the mean (range) age was 51.7 (40.0-83.0) years. Female sex, general severity, number, size, and facial severity of cNFs were negatively associated with QoL, as demonstrated by increased total Skindex scores. QoL had the largest association with the number of cNFs and presence of facial cNFs. Increasing number of cNFs was associated with worse QoL, and even individuals with a low cNF burden (<10 total cNFs) experienced a decrease in QoL.

Conclusions and Relevance

The results of this study suggest that reducing cNF number, particularly on the face, may be associated with improved QoL in individuals with NF1. In addition, early intervention before the development of numerous tumors may lead to the highest benefit in QoL. These data potentially provide insight into which individuals and cNF tumors may benefit most from therapy and highlights the utility of a completely decentralized, photograph-validated and age-controlled study for rare genetic disease. This cohort will allow analysis of disease and tumor heterogeneity after full phenotypic expression is achieved in NF1 and potentially serves as an example in its design for other rare diseases that struggle from poor recruitment.

Quality of Life in Children with Neurofibromatosis Type 1: Agreement between Parents and Patients, and the Role of Disease Severity and Visibility

BACKGROUND

Neurofibromatosis type 1 (NF1) is a genetic disorder that affects multiple systems in the body, often leading to physical disfigurements and a wide range of clinical symptoms. This study aims to investigate the relationship between NF1 severity and visibility and the quality of life (QoL) in children.

METHODS

The Pediatric Quality of Life Inventory (PedsQL) and a modified version of the Ablon scale were used to assess QoL and NF1 severity and visibility, respectively. Self-reported and parent-reported QoL scores were compared, and the associations between NF1 severity/visibility and QoL were explored.

RESULTS

Thirty-eight pediatric NF1 patients and their parents were enrolled. QoL scores did not differ significantly between patient self-reports and parent reports. However, correlational analyses revealed that higher NF1 severity was associated with lower physical QoL in patients, and greater NF1 visibility was linked to lower physical and social QoL. For parents, higher NF1 severity correlated with lower school functioning, whereas NF1 visibility did not show a significant correlation with QoL.

CONCLUSION

The severity and visibility of NF1 have distinct impacts on various aspects of QoL in children, highlighting the need for tailored interventions that address both physical and psychological challenges. These findings underscore the importance of comprehensive care approaches in managing NF1 in pediatric populations.

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.

Biomarker Landscape in RASopathies

RASopathies are a group of related genetic disorders caused by mutations in genes within the RAS/MAPK signaling pathway. This pathway is crucial for cell division, growth, and differentiation, and its disruption can lead to a variety of developmental and health issues. RASopathies present diverse clinical features and pose significant diagnostic and therapeutic challenges. Studying the landscape of biomarkers in RASopathies has the potential to improve both clinical practices and the understanding of these disorders. This review provides an overview of recent discoveries in RASopathy molecular profiling, which extend beyond traditional gene mutation analysis. mRNAs, non-coding RNAs, protein expression patterns, and post-translational modifications characteristic of RASopathy patients within pivotal signaling pathways such as the RAS/MAPK, PI3K/AKT/mTOR, and Rho/ROCK/LIMK2/cofilin pathways are summarized. Additionally, the field of metabolomics holds potential for uncovering metabolic signatures associated with specific RASopathies, which are crucial for developing precision medicine. Beyond molecular markers, we also examine the role of histological characteristics and non-invasive physiological assessments in identifying potential biomarkers, as they provide evidence of the disease's effects on various systems. Here, we synthesize key findings and illuminate promising avenues for future research in RASopathy biomarker discovery, underscoring rigorous validation and clinical translation.

Efficacy of Trametinib in Neurofibromatosis Type 1-Associated Gastrointestinal Stromal Tumors: A Case Report

Trametinib, an MEK inhibitor, may offer a new therapeutic option for patients with NF1-related GIST.

Whole-Body Positron Emission Tomography with 18F-Fluorodeoxyglucose/Magnetic Resonance Imaging as a Screening Tool for the Detection of Malignant Transformation in Individuals with Neurofibromatosis Type 1

Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of death in patients with neurofibromatosis type 1. They can result from premalignant neurofibromas, including neurofibromas with atypia and atypical neurofibromatous neoplasms of uncertain biologic potential. Some phenotypic characteristics have been described as associated with their development. The aim of this study was to outline our use of whole-body positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging in adults with neurofibromatosis type 1, especially in the screening of asymptomatic individuals with a higher risk of developing an MPNST, and to study its impact on neurofibroma classification (malignant vs premalignant) and MPNST staging over time. Individuals with neurofibromatosis type 1 who underwent a positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging between 2017 and 2021 were included, analyzing separately the screened population. Maximum standard uptake value and diffusion-weighted imaging were assessed. Biopsy/surgery confirmed the diagnosis. In all, 345 positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging were performed in 241 patients, including 149 asymptomatic (62%) but at-risk patients. Eight MPNSTs in 8 screened individuals (5%), 6 neurofibromas with atypia in 4 individuals (3%), and 29 atypical neurofibromatous neoplasms of uncertain biologic potential in 23 individuals (15%) were diagnosed. Over time, the proportion of grade 3 MPNST and the malignant/premalignant ratio in screened individuals significantly decreased (P = .03 and P < .001, respectively). This study emphasizes the diagnostic and screening performances of whole-body positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging in adults with neurofibromatosis type 1.

An evaluation of computerized attention and executive function measures for use with school age children with neurofibromatosis type 1

The present study investigated the performance of children with neurofibromatosis type 1 on computerized assessments of attention and executive function. Relations to ADHD symptomatology were also examined. Participants included 37 children (20 male) with NF1 (9-13 years; Mage = 11.02). Participants completed the NIH Toolbox Dimensional Change Card Sort, List Sort Working Memory (LSWM), and Flanker tasks, as well as Cogstate Identification and One Back tests. ADHD symptomatology was assessed using the K-SADS. Average performance was significantly different from the normative mean on every measure, except LSWM. The NIH Toolbox Flanker and Cogstate Identification tasks detected the highest proportion of participants with at least mild difficulty, and the Cogstate Identification task detected the highest proportion of participants with severe difficulty. Analyses revealed significant relations with ADHD symptomatology for two NIH toolbox tasks. The various computerized measures of attention and executive function offer different information when working with school age children with NF1. The NIH Flanker may offer the most room for change and offers face validity, which may be beneficial for clinical trials research. However, the LSWM shows most support for relations with behavioral indicators of attention and executive challenges.

Minimally Invasive Plasma Device Management of Multiple Benign Skin Cancers Associated with Rare Genodermatoses-Case Series and Review of the Therapeutic Methods

Background: Non-melanocytic benign skin tumours encompass a diverse group of lesions, classified based on their cellular origin, such as epidermal, vascular, fibrous, neural, muscle, and adnexal tumours. Though they often reveal solitary lesions, multiple skin tumours focus on genodermatoses. Each syndrome exhibits distinct clinical characteristics and potential complications, including cutaneous and extra-cutaneous malignancies, some of which are potentially life-threatening. Diagnosing genetic syndromes is complex and requires numerous histopathological and immunohistochemistry tests due to similarities between the adnexal tumours and basal cell carcinoma upon pathology. Methods: To illustrate the clinical practice, we conducted a retrospective case study that included eleven patients with genodermatoses referred to a tertiary dermatology clinic from September 2018 to April 2024. We have also conducted a research study on available treatment modalities in this setting. Results: Five patients with excellent aesthetic results were treated using a recently approved FDA plasma device. After searching SCOPUS and PubMed database records, we assessed 96 original articles to present current knowledge regarding the dermato-surgical approach. Conclusions: Multiple skin tumours, especially on the face, may significantly affect patients' quality of life and have psychological consequences. An appropriate treatment selection tailored to the patient's needs should be provided. There is no standardised treatment for multiple benign tumours in genodermatoses, and selected methods with varying efficacy are employed. We presented the utility of a new plasma device in these settings.

Analysis of visual evoked potentials in patients with neurofibromatosis type 1: new concepts

Introduction

Neurofibromatosis type 1 (NF type 1) is an autosomal dominant disease with typical clinical manifestations, such as skin lesions, Lisch nodules, optic pathway gliomas, and neurofibromas, caused by the mutation of the NF1 gene. Visual evoked potentials (VEP) present a measure of the electrophysiological response of visual cortex to a visual stimulus. The role of VEP in the pathophysiology of NF type 1 is very complex and requires additional research.

The Aim

We examined the differences between NF type 1 patients with normal and altered VEP and analyzed the correlation between the prolongation of P100 latency and disease severity.

Materials and methods

Two groups were formed: a control group and a study group with NF type 1 patients. Based on the control group analysis, a threshold value for a normal VEP finding of 116 ms was obtained, and it was used to divide the study group into subgroups with normal and altered VEP. We proceeded with examining the differences in clinical manifestations of the disease between the subgroups, after which we checked if there is a correlation between the prolongation of the P100 latency and the severity of the clinical picture according to the Riccardi scale. Statistical analysis was performed using the Pearson chi-square test and the Spearman correlation test in the program SPSS 28.0, with levels of statistical significance p = 0.05 and p = 0.001.

Results

In the group with the abnormal VEP we found a statistically significant more frequent occurrence of optic tract glioma (p = 0.008), tumors (p = 0.032), epilepsy (p = 0.043), and cognitive disorders (p = 0.028), while the other clinical signs had an equal prevalence in both groups. A moderately strong correlation (r s = 0.665) was observed between the prolongation of P100 latency and the severity of the clinical picture.

Conclusion

Our results showed the important role of VEP in the description of clinical phenotypes of NF type 1. The authors of the study propose VEP to be included in the diagnostic algorithms designed for patients with NF type 1.

Beyond the Band-Aid: Robot-Assisted Laparoscopy for Splenic Aneurysms. A Systematic Review

INTRODUCTION

Splenic artery aneurysm (SAA) is characterized by a weakening and bulging of splenic artery. Robot-assisted laparoscopic surgery is a minimally invasive surgical technique. This systematic review aimed to assess the use of robot-assisted laparoscopic surgery to manage SAA.

METHODOLOGY

Five medical databases were used to identify studies that investigated the use of robotic devices in laparoscopic SAA management in humans. Original, peer-reviewed articles were included. Two authors independently screened articles and extracted data on factors including patient demographics, surgical procedures, and outcomes.

RESULTS

The PRISMA search identified seven studies with a total of 28 patients who underwent robot-assisted laparoscopic surgery for SAA. The studies reported successful surgeries using various techniques, including end-to-end anastomosis, ligation, and graft placement. 3D printed models were used in one study as an aid for pre-operative surgery planning. Mean operation time was 210 minutes, and three complications were reported (robotic arm failure during surgery and two conversions to open surgery).

DISCUSSION AND FUTURE DIRECTIONS

Robot-assisted laparoscopic surgery offers several advantages over traditional open surgery for SAA management. However, more research is needed to confirm these potential benefits and establish robot-assisted laparoscopic surgery as a standard treatment option for SAA. Future studies should involve larger patient groups, compare this method to traditional techniques, and evaluate its cost-effectiveness. Additionally, incorporating advancements like mixed reality for pre-operative planning and 3D printing to improve surgical planning and patient communication.

Dermoscopy aids in differentiating café-au-lait macules from congenital melanocytic nevi in patients with darker skin phototypes

Dermoscopy aids in the diagnosis and management of pigmented growths and disorders of pigmentation in children. However, there is limited literature on the dermoscopic appearance of café-au-lait macules (CALMs) and congenital melanocytic nevi in patients with dark skin. We report two cases of young children with dark skin and many hyperpigmented patches in whom dermoscopy was utilized to accurately diagnose CALMs and facilitate testing for neurofibromatosis.

Neurofibromatosis Type 1-Retinal Alterations Detectable with Optical Coherence Tomography Angiography

Neurofibromatosis type 1 (NF 1) is a multisystemic genetic disorder involving aberrant proliferation of multiple tissues of a neural crest origin. It represents a tumor predisposition syndrome characterized by a wide range of clinical manifestations, such as benign tumors, which primarily affect the skin and the nervous system. The most frequent clinical signs of NF 1 include café-au-lait spots all over the surface of the skin and axillary freckling; however, these signs can be accompanied by more severe manifestations such as the growth of both benign and malignant nervous system tumors and skeletal dysplasia, as well as a wide range of ocular manifestations. We report the rare case of retinal microvascular alterations and choroidal nodules in a 15 year old male patient with NF 1, detectable on optical coherence tomography angiography (OCTA). The hyperreflective choroidal nodules modified the profile of the choroidal vasculature. The retinal microvascular alterations in the form of clustered capillaries were detected in the superficial capillary plexus located nasally to the macular region. Retinal vascular abnormalities undetectable on fundus photography or fundoscopy can be present in patients with NF 1. Indirect ophthalmoscopy of our study patient was unremarkable. However, retinal vascular abnormalities were seen on OCTA scans in the superficial capillary plexus and choroidal nodules were detected on raster OCT scans. OCTA represents a useful imaging technique for detecting retinal microvascular abnormalities, which can be considered additional distinctive signs of NF 1.

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.

Cardiac screening in pediatric patients with neurofibromatosis type 1: similarities with Noonan syndrome?

Both Neurofibromatosis type 1 (NF1) and Noonan syndrome (NS) are RASopathies. Characteristic cardiac phenotypes of NS, including specific electrocardiographic changes, pulmonary valve stenosis and hypertrophic cardiomyopathy have not been completely studied in NF1.

PURPOSE

The aims of this study were to assess: (1) similarities in the prevalence and types of ECG and conventional echocardiographic findings described in NS in asymptomatic patients with NF1, and (2) the presence of discrete myocardial dysfunction in NF1 patients using myocardial strain imaging.

METHODS

Fifty-eight patients with NF1 (ages 0-18 years), and thirty-one age-matched healthy controls underwent cardiac assessment including blood pressure measurements, a 12-lead ECG, and detailed echocardiography. Quantification of cardiac chamber size, mass and function were measured using conventional echocardiography. Myocardial strain parameters were assessed using 2-Dimensional (2D) Speckle tracking echocardiography.

RESULTS

Asymptomatic patients with NF1 had normal electrocardiograms, none with the typical ECG patterns described in NS. However, patients with NF1 showed significantly decreased calculated Z scores of the left ventricular internal diameter in diastole and systole, reduced left ventricular mass index and a higher incidence of cardiac abnormal findings, mainly of the mitral valve, in contrast to the frequently described types of cardiac abnormalities in NS. Peak and end systolic global circumferential strain were the only significantly reduced speckle tracking derived myocardial strain parameter.

CONCLUSIONS

Children with NF1 demonstrated more dissimilarities than similarities in the prevalence and types of ECG and conventional echocardiographic findings described in NS. The role of the abnormal myocardial strain parameter needs to be explored.

Distinct attentional and executive profiles in neurofibromatosis type 1: Is there difference with primary attention deficit-hyperactivity disorder?

PURPOSE

Attentional and executive dysfunctions are the most frequent cognitive disorders in neurofibromatosis type 1 (NF1), with a high prevalence of attention deficit-hyperactivity disorder (ADHD). We (i) compared attentional profiles between NF1 children with and without ADHD and children with primary ADHD criteria and (ii) investigated the possible relationship between attentional disorders and "unidentified bright objects" (UBOs) in NF1.

METHODS

This retrospective study included 47 NF1 children, 25 with ADHD criteria (NF1+adhd group), matched for age, sex, and cognitive level with 47 children with primary ADHD (ADHD group). We collected computer task (sustained-attention, visuomotor-decision, inhibition, and cognitive-flexibility tasks) scores normalized for age and sex, and brain magnetic resonance imaging data.

RESULTS

(i) Working memory was impaired in all groups. (ii) Omissions (p < 0.002) and response-time variability (p < 0.05) in sustained-attention and visuomotor-decision tasks and errors (p < 0.02) in the cognitive-flexibility task were lower for the NFI+adhd and ADHD groups than for the NF1-no-adhd group. (iii) The NF1+adhd group had slower response times (p ≤ 0.02) for inhibition and visuomotor-decision tasks than the other groups. (iv) We found no relevant association between cognitive performance and UBOs.

CONCLUSIONS

NF1 children with ADHD have an attentional and executive functions deficit profile similar to that of children with primary ADHD, but with a slower response-time, increasing learning difficulties. The atypical connectivity of fronto-striatal pathways, poorer dopamine homeostasis, and increased GABA inhibition observed in NF1 renders vulnerable the development of the widely distributed neural networks that support attentional, working-memory, and executive functions.

The genetic spectrum of NF1 variants in 10 unrelated Chinese families with neurofibromatosis type 1

OBJECTIVES

To investigate the clinical and genetic features in a cohort of Chinese families with neurofibromatosis type 1 (NF1).

METHODS

The clinical information of 21 patients with NF1 in 10 families was retrospectively analyzed. To broaden the genetic spectrum of NF1, multiplex ligation-dependent probe amplification analysis was performed first, followed by the whole-exome sequencing, in order to identify pathogenic or potentially pathogenic variants of NF1 gene in 10 unrelated Chinese families.

RESULTS

Nine different NF1 variants were identified in all 10 families. Of these, 7 were known pathogenic variants and included the exon 1 deletion, exons 1-58 deletion, c.5401C>T (p.Q1801*), c.2291-2A>C, c.484C>T (p.Q162*), c.4922G>A (p.W1641*) and c.1019_1020del (p.S340Cfs*25). The 2 novel variants were c.5197T>C (p.S1733P) and c.783_797delinsC (p.K261Nfs*25). The p.S1733P variant was classified as a variant of uncertain significance, while p.K261Nfs*25 was classified as pathogenic. Hence, the positive detection rate of NF1 variants was 100% (10/10). While the truncating variants were responsible for 60.0% (6/10) of the cases, the splicing variant was responsible for 10% (1/10) of the cases.

CONCLUSION

We identified 2 novel heterozygous variants (c.5197T>C and c.783_797delinsC) in the NF1 gene, which broadens the genetic spectrum of the NF1 gene.

Genotype-Phenotype Correlation in Neurofibromatosis Type 1: Evidence for a Mild Phenotype Associated with Splicing Variants Leading to In-Frame Skipping of NF1 Exon 24 [19a]

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disorder caused by loss-of-function variants in the NF1 gene. As of 20 November 2023, over 5000 distinct pathogenic or likely pathogenic variants have been reported in public databases. However, only a few NF1 genotype-phenotype correlations have been established so far. In this study, we present findings on 40 individuals with NF1, comprising 26 unrelated probands and 14 affected relatives, who carry one of nine NF1 heterozygous pathogenic splicing variants, all of which result in the in-frame skipping of exon 24 [19a] (NM_000267.3:r.3114_3197del, p.Asn1039_Arg1066del). These variants include c.3114-2A>G, c.3114-1G>A, c.3196A>G, c.3197G>A, c.3197G>T, c.3197+1G>A, c.3197+1G>T, c.3197+2T>C, and c.3197+3A>T. Among individuals with these variants, none exhibit externally visible plexiform neurofibromas, histopathologically confirmed cutaneous or subcutaneous neurofibromas, symptomatic spinal neurofibromas, or symptomatic optic pathway gliomas. The most prevalent, and sometimes sole, clinical feature observed in this cohort is multiple café-au-lait macules, with or without skinfold freckles: 85% and 60.5% of the individuals display six or more café-au-lait macules and freckles, respectively. In comparison to established NF1 genotype-phenotype correlations, these patients demonstrate highly similar clinical presentations to those associated with the NF1 pathogenic variant c.2970_2972del (p.Met992del), known for resulting in the mildest clinical features. Despite the generally mild phenotype, cognitive impairment, developmental delay, and/or learning difficulties are still observed in 33.3% of these patients, suggesting that learning challenges remain a prominent aspect of the phenotypic presentation in these individuals and necessitate specialized care. This newly established genotype-phenotype correlation will assist clinicians in improving the management of patients harboring NF1 exon 24 [19a] skipping variants and provide a new therapeutic target for NF1 treatment.

Dietary intervention rescues a bone porosity phenotype in a murine model of Neurofibromatosis Type 1 (NF1)

Neurofibromatosis type 1 (NF1) is a complex genetic disorder that affects a range of tissues including muscle and bone. Recent preclinical and clinical studies have shown that Nf1 deficiency in muscle causes metabolic changes resulting in intramyocellular lipid accumulation and muscle weakness. These can be subsequently rescued by dietary interventions aimed at modulating lipid availability and metabolism. It was speculated that the modified diet may rescue defects in cortical bone as NF1 deficiency has been reported to affect genes involved with lipid metabolism. Bone specimens were analyzed from wild type control mice as well as Nf1Prx1-/- (limb-targeted Nf1 knockout mice) fed standard chow versus a range of modified chows hypothesized to influence lipid metabolism. Mice were fed from 4 weeks to 12 weeks of age. MicroCT analysis was performed on the cortical bone to examine standard parameters (bone volume, tissue mineral density, cortical thickness) and specific porosity measures (closed pores corresponding to osteocyte lacunae, and larger open pores). Nf1Prx1-/- bones were found to have inferior bone properties to wild type bones, with a 4-fold increase in the porosity attributed to open pores. These measures were rescued by dietary interventions including a L-carnitine + medium-chain fatty acid supplemented chow previously shown to improve muscle histology function. Histological staining visualized these changes in bone porosity. These data support the concept that lipid metabolism may have a mechanistic impact on bone porosity and quality in NF1.

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.

Magnetic Resonance Imaging of Central Nervous System Manifestations of Type 1 Neurofibromatosis: Pictorial Review and Retrospective Study of Their Frequency in a Cohort of Patients

Background: type 1 neurofibromatosis (NF1) is the most common neurocutaneous disorder, and it is an inherited condition that causes a tumour predisposition. Central nervous system (CNS) manifestations are a significant cause of morbidity and mortality in NF1. We provide a pictorial review of neuroradiological features of NF1, with emphasis on magnetic resonance imaging (MRI), and we assess the frequency of those features on a cohort of NF1 patients. Methods: we retrospectively evaluated all patients with a diagnosis of NF1 who underwent MRI of the spine and brain in our centre over a period of almost 5 years. A total of 74 patients were enrolled, 28 males and 46 females, with a mean age of 21 ± 12.67 years. The frequency of CNS manifestations encountered in our cohort of NF1 patients was assessed and compared with the data found in other studies published in the literature. Results: many of our findings were in line with the literature, and possible interpretations for those that turned out to be different were suggested in the discussion. Conclusion: imaging plays a central role in the diagnosis and management of NF1, and the knowledge of CNS manifestations could be critical for its early detection and identification, such as for treatment planning and prognostic implications.

Cancer predisposing syndromes in childhood and adolescence pose several challenges necessitating interdisciplinary care in dedicated programs

Introduction

Genetic disposition is a major etiologic factor in childhood cancer. More than 100 cancer predisposing syndromes (CPS) are known. Surveillance protocols seek to mitigate morbidity and mortality. To implement recommendations in patient care and to ascertain that the constant gain of knowledge forces its way into practice specific pediatric CPS programs were established.

Patients and methods

We retrospectively analyzed data on children, adolescents, and young adults referred to our pediatric CPS program between October 1, 2021, and March 31, 2023. Follow-up ended on December 31, 2023.

Results

We identified 67 patients (30 male, 36 female, 1 non-binary, median age 9.5 years). Thirty-five patients were referred for CPS surveillance, 32 for features suspicious of a CPS including café-au-lait macules (n = 10), overgrowth (n = 9), other specific symptoms (n = 4), cancer suspicious of a CPS (n = 6), and rare neoplasms (n = 3). CPS was confirmed by clinical criteria in 6 patients and genetic testing in 7 (of 13). In addition, 6 clinically unaffected at-risk relatives were identified carrying a cancer predisposing pathogenic variant. A total of 48 patients were eventually diagnosed with CPS, surveillance recommendations were on record for 45. Of those, 8 patients did not keep their appointments for various reasons. Surveillance revealed neoplasms (n = 2) and metachronous tumors (n = 4) by clinical (n = 2), radiological examination (n = 2), and endoscopy (n = 2). Psychosocial counselling was utilized by 16 (of 45; 35.6%) families.

Conclusions

The diverse pediatric CPSs pose several challenges necessitating interdisciplinary care in specified CPS programs. To ultimately improve outcome including psychosocial well-being joint clinical and research efforts are necessary.

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.

Epilepsy in Legius syndrome: Coincidence or causation?

Legius syndrome is a rare genetic disorder, caused by heterozygous SPRED1 pathogenic variants, which shares phenotypic features with neurofibromatosis type 1 (NF1). Both conditions typically involve café-au-lait macules, axillary freckling, and macrocephaly; however, patients with NF1 are also at risk for tumors, such as optic nerve gliomas and neurofibromas. Seizure risk is known to be elevated in NF1, but there has been little study of this aspect of Legius syndrome. The reported epilepsy incidence is 3.3%-5%, well above the general population incidence of ~0.5%-1%, but the few reports in the literature have very little data regarding epilepsy phenotype. We identified two unrelated individuals, both with Legius syndrome and epilepsy, and performed thorough phenotyping. One individual's mother also had Legius syndrome and now-resolved childhood epilepsy, as well as reports of more distant relatives who also had multiple café-au-lait macules and seizures. Both probands had experienced childhood-onset focal seizures, with normal brain MRI. In one patient, EEG later showed apparently generalized epileptiform abnormalities. Based on the data from this small case series and literature review, seizure risk is increased in people with Legius syndrome, but the epilepsy prognosis appears to be generally good, with patients having either self-limited or pharmacoresponsive courses.

Understanding chronic pain in Neurofibromatosis Type 1 using the Neurofibromatosis Pain Module (NFPM)

Neurofibromatosis Type 1 (NF1) is an autosomal dominant genetic disorder that can cause an individual significant chronic pain (CP). CP affects quality of life and daily functioning, yet there are limited effective treatments for CP within NF1. The current study describes the impact of CP using the Neurofibromatosis Pain Module (NFPM). The NFPM is a self-reported clinical assessment that evaluates the impact of CP across multiple domains (e.g., interference, severity, tolerance, and symptomology) and three prioritized pain regions. A cross-sectional study (N = 242) asked adults with NF1 to describe and rate their pain using the NFPM. The results indicated that they reported moderate pain severity (M = 6.6, SD = 2.0) on a 0-10 scale, that 54% (n = 131) had been in pain at least 24 days in the last 30, for 75% (n = 181) sleep was affected, and 16% reported that nothing was effective in reducing their CP for their primary pain region. The current results extend previously published work on CP within adults with NF1 and indicate that more emphasis on understanding and ameliorating CP is required. The NFPM is a sensitive clinical measure that provides qualitative and quantitative responses to inform medical providers about changes in CP.

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.

Quality of life in individuals with neurofibromatosis type 1 associated cutaneous neurofibromas: validation of the Dutch cNF-Skindex

BACKGROUND

Almost all patients with Neurofibromatosis type 1 (NF1) develop cutaneous neurofibroma (cNF), benign dermal tumours that have a large impact on the patient's Quality of Life (QoL). The French cNF-Skindex is the first questionnaire to specifically assess cNF-related QoL in patients with NF1. We aimed to adapt and validate a Dutch version of the cNF-Skindex.

METHODS

The questionnaire was translated using forward and backwards translation, and subsequently administered to a sample of 59 patients on two separate occasions. Feasibility was evaluated by the presence of floor/ceiling effects. Reliability was assessed by evaluating internal consistency and test-retest reliability, by calculating Cronbach's alpha and Spearman's rank correlation coefficients. The EQ-5D-5L and SF-36 were used to evaluate convergent validity, using Spearman's rank correlation coefficients. An exploratory factor analysis was performed to study the data's internal structure. Multivariable linear regression was used to model the relationship between patient characteristics and the cNF-Skindex.

RESULTS

The Dutch cNF-Skindex demonstrated excellent feasibility and reliability (Cronbach's alpha 0.96, test-retest correlation coefficient 0.88). Convergent validity was confirmed for the EQ-5D-5L and relevant SF-36 scales. All items and subdomains from the original questionnaire were confirmed following exploratory factor analysis. The patient characteristics included in the multivariable linear regression were not significantly associated with the cNF-Skindex score.

CONCLUSIONS

The Dutch cNF-Skindex displayed excellent psychometric properties, enabling use in the Netherlands.

NF1 with 47,XYY mosaicism diagnosed by mandibular neurofibromas

Neurofibromatosis type 1 (NF1) is an autosomal dominant nevus disease characterized by multiple manifestations, primarily café-au-lait macules and neurofibromas. Here, we present the case of an NF1 patient with 47,XYY mosaicism whose diagnosis was prompted by café-au-lait macules on the skin and mandibular neurofibromas. Targeted next-generation sequencing of the patient's blood sample revealed a novel frameshift mutation in NF1 (NM_000267.3:c.6832dupA:p.Thr2278Asnfs*8) that is considered a pathogenic variant.

Facial Features of Hereditary Cancer Predisposition

In the age of telehealth medicine, an individual's facial features may provide the only physical clues signaling the presence of a heritable cancer predisposition syndrome. These syndromes include APC-associated polyposis, Birt-Hogg-Dubé syndrome, CYLD cutaneous syndrome, hereditary leiomyomatosis and renal cell cancer, multiple endocrine neoplasia, neurofibromatosis type 1, Peutz-Jeghers syndrome, PTEN hamartoma tumor syndrome, and tuberous sclerosis complex 1 and 2, among others. Correctly identifying characteristic features is important for genetic and nongenetic specialists as early detection can enable prompt intervention, improving patient outcomes. Advancements in the availability of genetic testing allow patients and their relatives to have more information about their genetic risk profile than before. These changes in clinical pathways, combined with improvements in screening and risk-reducing treatment, highlight the need to outline the cutaneous and morphologic features of high-risk cancer syndromes for clinicians. In this review, we describe the important facial features of hereditary cancer predisposition, with emphasis on diagnosis, cutaneous and extracutaneous manifestations, and screening.

Low-grade glioma in children with neurofibromatosis type 1: surveillance, treatment indications, management, and future directions

Neurofibromatosis type 1 (NF1) is an autosomal dominant cancer predisposition syndrome characterized by the development of both central and peripheral nervous system tumors. Low-grade glioma (LGG) is the most prevalent central nervous system tumor occurring in children with NF1, arising most frequently within the optic pathway, followed by the brainstem. Historically, treatment of NF1-LGG has been limited to conventional cytotoxic chemotherapy and surgery. Despite treatment with chemotherapy, a subset of children with NF1-LGG fail initial therapy, have a continued decline in function, or recur. The recent development of several preclinical models has allowed for the identification of novel, molecularly targeted therapies. At present, exploration of these novel precision-based therapies is ongoing in the preclinical setting and through larger, collaborative clinical trials. Herein, we review the approach to surveillance and management of NF1-LGG in children and discuss upcoming novel therapies and treatment protocols.

Chronic kidney disease with malignant peripheral nerve sheath tumor of the ureter: a case report

Malignant peripheral nerve sheath tumors (MPNSTs) are a complex group of malignant tumors originating from nerve cells or benign peripheral nerve sheath tumors and are commonly found in major plexus/nerve root sites such as the limbs, head, and neck. Malignant peripheral nerve sheath tumors originating in the ureter are extremely rare. Herein, we report the case of a 63-year-old patient with a malignant peripheral nerve sheath tumor of the right ureter who underwent laparoscopic radical resection of the right kidney and ureter. The patient also had stage 5 chronic kidney disease (CKD). Therefore, chemotherapy and radiotherapy were not considered. No tumor recurrence was observed during the follow-up period.

Social cognition in children with neurofibromatosis type 1

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a genetic pathology that can lead to impaired social functioning that has a negative impact on patients' quality of life. To date, although the hypothesis of impaired social cognition has been proposed as a potential explanation for these difficulties, very few studies have focused on theory of mind in children with NF1. Furthermore, other complex sociocognitive abilities have never been investigated. The aim of the present study was to assess theory of mind, moral reasoning, and social information processing in children with NF1 compared with a control group.

METHOD

We administered the Paediatric Evaluation of Emotions, Relationships and Socialization® to 38 children with NF1 aged between 8 years and 16 years 11 months (mean = 11.4, SD = 2.3) and 43 control children with comparable sociodemographic characteristics.

RESULTS

Patients performed significantly worse than controls on moral reasoning and social information processing tests, but there was no significant difference on theory of mind.

CONCLUSIONS

These results seem to confirm the presence of social cognition difficulties in NF1 that could explain, at least in part, their social difficulties, although not all dimensions are concerned. The differences between the processes we assessed are discussed in relation to the methodologies used to measure them, and raises questions about the complementarity of traditional tools and more ecological assessments.

Giant Cystic Pheochromocytoma Associated With Neurofibromatosis Type 1: A Case Report

Pheochromocytomas are tumors that develop from the chromaffin cells of the adrenal medulla. More than 40% of cases of pheochromocytomas are associated with genetic conditions such as neurofibromatosis type 1 (NF1) or von Hippel-Lindau syndrome. Cystic pheochromocytomas are rare, generally asymptomatic, and thus of bigger size at the time of diagnosis. Surgical treatment is necessary to prevent cardiovascular morbidity and malignancy risk. We report the case of a 27-year-old patient admitted for further examination of a left adrenal mass that was discovered by an abdominal CT scan in the context of abdominal pain associated with hypertension evolving for three years. The clinical examination showed the presence of multiple café au lait spots, axillary and inguinal freckling with two dermal neurofibromas diagnosed clinically, as well as Lisch nodules on bilateral ophthalmic examination, thus meeting the clinical criteria for the diagnosis of NF1. The clinical laboratory investigation showed elevated urinary metanephrine and normetanephrine levels. CT scan examination showed a 10 cm left adrenal cystic mass on abdominal CT. This mass uptake of the radioligand in metaiodobenzylguanidine (MIBG) scintigraphy without secondary extra-adrenal localization allowed the diagnosis of a seemingly benign cystic pheochromocytoma to be made. The patient was put on presurgical drug preparation with volume expansion and then underwent left unilateral adrenalectomy. The histopathological study was in favor of a rather aggressive cystic pheochromocytoma with a pheochromocytoma of the adrenal gland scaled (PASS) score of 9. Blood pressure and urine catecholamines at seven days, three months, six months, and one year after surgery were normalized. Cystic pheochromocytoma is a rare tumor with a potentially poor prognosis. It is characterized by a more insidious evolution and a larger volume at diagnosis. It should be considered a diagnosis in patients with a cystic adrenal mass or an extra-adrenal mass with fluctuating blood pressure during surgery. This case illustrates the importance of both presurgical preparation and screening for pheochromocytoma in neurofibromatosis type 1.

Epilepsy in neurofibromatosis type 1: Prevalence, phenotype, and genotype in adults

PURPOSE

Studies have shown an increased risk of epilepsy in patients with neurofibromatosis type 1 (NF1). However, most reports focus on the pediatric population. In this study, we describe the trajectory of patients with NF1 and epilepsy beyond childhood.

METHODS

Patients with NF1 ≥18 years-old consecutively seen at a multidisciplinary neurofibromatosis clinic during a four-year period were prospectively enrolled and offered routine EEG, MRI, and genetic testing. The lifelong and point prevalence of epilepsy in patients with NF1 were calculated. Demographic, genetic, radiological, and clinical features found to be statistically associated with having received a diagnosis of epilepsy were incorporated into a logistic regression model.

RESULTS

Among 113 patients with NF1 included in this study (median age at study inclusion: 33 years), the lifelong prevalence of epilepsy was 11% (CI95%=6-18%) and point prevalence 7% (CI95%= 3-13%). Most patients (73%) were diagnosed with epilepsy before the age of 18 and achieved seizure-freedom by adulthood. At study inclusion, three-quarters of patients with a diagnosis of epilepsy had been seizure-free for more than one year and a third had resolved epilepsy. A routine EEG with epileptiform discharges had a sensitivity of 25% (CI95%=3-65) and specificity of 99% (CI95%=93-100) for identifying adult patients with NF1 and unresolved epilepsy. A history of epilepsy was associated with having a low-grade glioma (OR: 38.2; CI95%=2.2-674.7; p<0.01), learning disability (OR: 5.7; CI95%=1.0-31.5; p<0.05), and no plexiform neurofibroma (OR: 0.05; CI95%=0.0-0.8; p=0.04). No single mutation type was associated with the development of epilepsy.

CONCLUSIONS

In patients with NF1, although resolution of epilepsy over time was observed in many cases, the prevalence of epilepsy was higher among adults with NF1 than that reported in the general population. Epileptogenesis in NF1 likely requires the combination of multiple genetic and environmental factors and suggests involvement of a network that spreads beyond the borders of a well-defined parenchymal lesion.

RASopathies: Evolving Concepts in Pathogenetics, Clinical Features, and Management

RASopathies refers to the group of disorders which are caused by a mutation in various genes of the RAS/MAPK (RAT sarcoma virus/Mitogen activated protein kinase) pathway. It includes many genes with varied functions, which are responsible for cell cycle regulation. As the mutation in one gene affects the entire pathway, there are many overlapping features among the various syndromes which are included under an umbrella term "RASopathies." However, neuroectodermal involvement is a unifying feature among these syndromes, which are caused by germline mutations affecting genes along this pathway. Recently, many other RASopathies have been described to involve blood vessels, lymphatics, and immune system. Also, many cutaneous mosaic disorders have been found to have mutations in the concerned pathway. The purpose of this article is to briefly review the pathogenesis of RASopathies with cutaneous manifestations, and summarise the features that can be helpful as diagnostic clues to dermatologists. As we understand more about the pathogenesis of the pathway at the cellular level, the research on genotype-phenotype correlation and therapeutic options broadens. Targeted therapy is in the clinical and preclinical trial phase, which may brighten the future of many patients.

Clinical and biological landscape of constitutional mismatch-repair deficiency syndrome: an International Replication Repair Deficiency Consortium cohort study

BACKGROUND

Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare and aggressive cancer predisposition syndrome. Because a scarcity of data on this condition contributes to management challenges and poor outcomes, we aimed to describe the clinical spectrum, cancer biology, and impact of genetics on patient survival in CMMRD.

METHODS

In this cohort study, we collected cross-sectional and longitudinal data on all patients with CMMRD, with no age limits, registered with the International Replication Repair Deficiency Consortium (IRRDC) across more than 50 countries. Clinical data were extracted from the IRRDC database, medical records, and physician-completed case record forms. The primary objective was to describe the clinical features, cancer spectrum, and biology of the condition. Secondary objectives included estimations of cancer incidence and of the impact of the specific mismatch-repair gene and genotype on cancer onset and survival, including after cancer surveillance and immunotherapy interventions.

FINDINGS

We analysed data from 201 patients (103 males, 98 females) enrolled between June 5, 2007 and Sept 9, 2022. Median age at diagnosis of CMMRD or a related cancer was 8·9 years (IQR 5·9-12·6), and median follow-up from diagnosis was 7·2 years (3·6-14·8). Endogamy among minorities and closed communities contributed to high homozygosity within countries with low consanguinity. Frequent dermatological manifestations (117 [93%] of 126 patients with complete data) led to a clinical overlap with neurofibromatosis type 1 (35 [28%] of 126). 339 cancers were reported in 194 (97%) of 201 patients. The cumulative cancer incidence by age 18 years was 90% (95% CI 80-99). Median time between cancer diagnoses for patients with more than one cancer was 1·9 years (IQR 0·8-3·9). Neoplasms developed in 15 organs and included early-onset adult cancers. CNS tumours were the most frequent (173 [51%] cancers), followed by gastrointestinal (75 [22%]), haematological (61 [18%]), and other cancer types (30 [9%]). Patients with CNS tumours had the poorest overall survival rates (39% [95% CI 30-52] at 10 years from diagnosis; log-rank p<0·0001 across four cancer types), followed by those with haematological cancers (67% [55-82]), gastrointestinal cancers (89% [81-97]), and other solid tumours (96% [88-100]). All cancers showed high mutation and microsatellite indel burdens, and pathognomonic mutational signatures. MLH1 or MSH2 variants caused earlier cancer onset than PMS2 or MSH6 variants, and inferior survival (overall survival at age 15 years 63% [95% CI 55-73] for PMS2, 49% [35-68] for MSH6, 19% [6-66] for MLH1, and 0% for MSH2; p<0·0001). Frameshift or truncating variants within the same gene caused earlier cancers and inferior outcomes compared with missense variants (p<0·0001). The greater deleterious effects of MLH1 and MSH2 variants as compared with PMS2 and MSH6 variants persisted despite overall improvements in survival after surveillance or immune checkpoint inhibitor interventions.

INTERPRETATION

The very high cancer burden and unique genomic landscape of CMMRD highlight the benefit of comprehensive assays in timely diagnosis and precision approaches toward surveillance and immunotherapy. These data will guide the clinical management of children and patients who survive into adulthood with CMMRD.

FUNDING

The Canadian Institutes for Health Research, Stand Up to Cancer, Children's Oncology Group National Cancer Institute Community Oncology Research Program, Canadian Cancer Society, Brain Canada, The V Foundation for Cancer Research, BioCanRx, Harry and Agnieszka Hall, Meagan's Walk, BRAINchild Canada, The LivWise Foundation, St Baldrick Foundation, Hold'em for Life, and Garron Family Cancer Center.

Impact of trametinib on the neuropsychological profile of NF1 patients

PURPOSE

The use of trametinib in the treatment of pediatric low-grade gliomas (PLGG) and plexiform neurofibroma (PN) is being investigated in an ongoing multicenter phase II trial (NCT03363217). Preliminary data shows potential benefits with significant response in the majority of PLGG and PN and an overall good tolerance. Moreover, possible benefits of MEK inhibitor therapy on cognitive functioning in neurofibromatosis type 1 (NF1) were recently shown which supports the need for further evaluation.

METHODS

Thirty-six patients with NF1 (age range 3-19 years) enrolled in the phase II study of trametinib underwent a neurocognitive assessment at inclusion and at completion of the 72-week treatment. Age-appropriate Wechsler Intelligence Scales and the Trail Making Test (for children over 8 years old) were administered at each assessment. Paired t-tests and Reliable Change Index (RCI) analyses were performed to investigate change in neurocognitive outcomes. Regression analyses were used to investigate the contribution of age and baseline score in the prediction of change.

RESULTS

Stable performance on neurocognitive tests was revealed at a group-level using paired t-tests. Clinically significant improvements were however found on specific indexes of the Wechsler intelligence scales and Trail Making Test, using RCI analyses. No significant impact of age on cognitive change was evidenced. However, lower initial cognitive performance was associated with increased odds of presenting clinically significant improvements on neurocognitive outcomes.

CONCLUSION

These preliminary results show a potential positive effect of trametinib on cognition in patients with NF1. We observed significant improvements in processing speed, visuo-motor and verbal abilities. This study demonstrates the importance of including neuropsychological evaluations into clinical trial when using MEK inhibitors for patients with NF1.

Neurofibromatosis Type 1: Optimizing Management with a Multidisciplinary Approach

Neurofibromatosis Type I (NF1) is a complex genetic condition that affects multiple organ systems and presents a unique set of challenges for clinicians in its management. NF1 is a tumor predisposition syndrome that primarily affect the peripheral and central nervous systems via the impact of haploinsufficiency upon neural crest lineage cells including Schwann cells, melanocytes, fibroblasts, etc. NF1 can further lead to pathology of the skin, bones, visual system, and cardiovascular system, all of which can drastically reduce a patient's quality of life (QOL). This review provides a comprehensive examination of the many specialties required for the care of patients with Neurofibromatosis Type 1 (NF1). We delve into the pathogenesis and clinical presentation of NF1, highlighting its diverse manifestations and the challenges they pose in management. The review underscores the importance of a multidisciplinary approach to NF1, emphasizing how such an approach can significantly improve patient outcomes and overall QOL. Central to this approach is the role of the NF expert, who guides a multidisciplinary team (MDT) comprising healthcare professionals from many areas of expertise. The MDT collaboratively addresses the multifaceted needs of NF1 patients, ensuring comprehensive and personalized care. This review highlights the need for further investigation to optimize the workflow for NF1 patients in an MDT setting, and to improve implementation and efficacy.

Histologic correlates of "Choroidal abnormalities" in Neurofibromatosis type 1 (NF1)

Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disorder characterized by proliferation of cells from neural crest origin. The most common manifestations are cutaneous, neurologic, skeletal and ocular. The distinction of NF1 from other syndromes with multiple café-au-lait macules may be difficult in the pediatric age group, and ocular findings, especially Lisch nodules (i.e., melanocytic hamartomas on the irides), are a useful, early diagnostic tool. In recent years, novel ocular manifestations descriptively referred to as "choroidal abnormalities", choroidal "hyperpigmented spots" and "retinal vascular abnormalities" have been recognized in NF1. Choroidal abnormalities (CA) appear as bright patchy nodules that can be best detected with near-infrared ocular coherence tomography imaging (NIR-OCT). Because of their high specificity and sensitivity for NF1, CA have been added as an ocular diagnostic criterion of NF1 as an alternative to Lisch nodules. Although CA are important ocular diagnostic criteria for NF1, the histologic correlates are controversial. We present the postmortem ocular pathology findings of an NF1 patient for whom clinical notes and ocular imaging were available. Findings in this patient included choroidal hyperpigmented spots on funduscopy and retinal vascular abnormalities, both of which have been reported to be closely associated with CA. Histologic examination of the eyes showed multiple clusters of melanocytes of varying sizes in the choroid. Pathologic review of 12 additional postmortem eyes from 6 NF1 patients showed multiple, bilateral choroidal melanocytic aggregates in all eyes. These findings suggest that the CA seen on NIR-OCT and the hyperpigmented spots seen clinically in NF1 patients are manifestations of multifocal choroidal melanocytic clusters, consistent with choroidal melanocytic hamartomas. Lisch nodules, often multiple, were present in all eyes with morphology that differed from the choroidal hamartomas. As such, although CA and Lisch nodules are melanocytic hamartomas, there are clear phenotypical differences in their morphologies.