Correction of cervical kyphoscoliosis, bisected spinal cord, and vertebral artery to epidural vein fistula in neurofibromatosis type 1.

Neurofibromatosis-1 (NF1) presents complex challenges due to its multisystemic effects, including kyphoscoliosis, dural ectasia, and arteriovenous fistulas (AVF). We present a case of a 31-year-old male with NF1 exhibiting severe cervical kyphoscoliosis, dural ectasia, a bisected cervical cord, and an arteriovenous fistula, highlighting the intricacies of managing such intricate cases. Rapid weakening in the patient's right arm and leg prompted imaging revealing severe cervical kyphotic deformity and a dural fold dividing the spinal cord. Surgical intervention addressed a high-flow arteriovenous fistula involving the right vertebral artery and an epidural vein, necessitating sacrifice of the artery. Posterior fusion and laminectomy were performed, resulting in stable neurological status postoperatively and significant improvement in sensory loss and weakness at three months. This case underscores the importance of a tailored posterior-only approach, involving dural fold release, to allow the spinal cord to relocate to a less tense position, thus demonstrating effective decompression in complex NF1 cases with concurrent kyphotic deformity and vertebral artery AVF.

A Cerebral Embolism Caused by a Malignant Peripheral Nerve Sheath Tumor in a Patient with Neurofibromatosis Type 1.

A 31-year-old man with neurofibromatosis type 1 (NF-1) had undergone resection of a malignant peripheral nerve sheath tumor (MPNST) on the buttock 3 months previously. He subsequently underwent mechanical thrombectomy for a hyperacute left middle cerebral artery embolism. Histopathologically, the emboli comprised neurofilament-positive pleomorphic tumor cells with geographic necrosis and conspicuous mitosis and were identified as MPNST. The patient died of respiratory failure due to lung MPNST metastasis on day 15 of hospitalization. To our knowledge, this is the first report of a spontaneous cerebral embolism due to MPNST in a NF-1 patient.

Solitary Isolated Oropharyngeal Neurofibroma Presenting With Dysphagia in the Setting of Von Recklinghausen's Disease.

A 24-year-old man with von Recklinghausen's disease presented with complaints of difficulty in swallowing for 6 months and change of voice for 3 months. He also had recent-onset difficulty in breathing. Telelaryngoscopy and subsequent contrast-enhanced computed tomography scan revealed a well-defined, smooth submucosal mass in the oropharynx (attached to the posterior pharyngeal wall, superior to the level of left aryepiglottic fold), obscuring the ipsilateral pyriform fossa, and nearly blocking the pharyngeal lumen. The mass was removed with endoscopic coblation-assisted laryngeal surgery, and subsequent histopathology revealed it to be neurofibroma. Neurofibromas are rare neoplasms to be encountered in the oropharynx. However, in the setting of von Recklinghausen's disease (neurofibromatosis type 1), one or more well-demarcated, submucosal nodular lesions in the upper aerodigestive tract may be considered as neurofibromas, and workup and treatment should be directed accordingly based on this clinical presumption. Endoscopic coblation during laryngeal surgery can effectively be used as a surgical tool to excise such lesions. It provides a relatively bloodless field compared to the conventional cold steel excision, and reduces the risk of complications at surgery and during the follow-up period. This clinical record illustrates the presentation and management of a solitary, isolated oropharyngeal neurofibroma in a man suffering from von Recklinghausen's disease. It further emphasizes the role of endoscopic coblation-assisted laryngeal surgery in this setup, and the need to maintain a low threshold of suspicion in having a provisional clinical diagnosis of such lesions.

Uncommon Thigh Mass in Neurofibromatosis Type 1: Unveiling Aggressive Epithelioid Sarcoma.

Background: Patients with neurofibromatosis type I (NF1) have an increased risk of developing soft-tissue sarcomas, particularly those related to the nervous system. Epithelioid sarcoma (ES) is an exceptionally rare subtype of soft-tissue sarcoma, with limited knowledge about its clinical presentation and optimal management in NF1. This report aims to provide insights into the characteristics and outcomes of ES in NF1 patients. Case description: A 37-year-old man with a history of NF1 presented with a progressively worsening mass on his right inner thigh. An MRI scan revealed a well-defined tissue mass originating from the adductor magnus muscle, later confirmed as ES through histopathology and immunohistochemistry. Considering poor local and general prognosis, the multidisciplinary team recommended salvage hip disarticulation, however the patient refused and opted for palliative marginal resection to reduce the tumour size. The patient's condition declined rapidly, and he succumbed six days after the surgery. Conclusion: This case highlights the rarity of ES in NF1 patients and underscores the potential for malignant tumour development in this population. Further research is needed to improve our understanding and management of sarcomas in the context of NF1. LEARNING POINTS: Patients with neurofibromatosis type 1 or von Recklinghausen's disease have a higher risk than those with other types of neurofibromatosis of developing benign or malignant soft-tissue tumours especially related to the nervous system.Epithelioid sarcoma is an extremely rare subtype of soft-tissue sarcoma and is exceptionally associated with neurofibromatosis type 1.A multidisciplinary approach remains essential in the diagnosis, management, and treatment of soft-tissue sarcomas in patients with neurofibromatosis type 1.

A Population Pharmacokinetic Assessment of the Effect of Food on Selumetinib in Patients with Neurofibromatosis Type 1-Related Plexiform Neurofibromas and Healthy Volunteers.

Selumetinib is clinically used for pediatric patients with neurofibromatosis type 1 and symptomatic, inoperable plexiform neurofibromas. Until recently, selumetinib had to be taken twice daily, after 2 hours of fasting and followed by 1 hour of fasting, which could be inconvenient. This population analysis evaluated the effect of low- and high-fat meals on the pharmacokinetic (PK) parameters of selumetinib and its active metabolite N-desmethyl selumetinib. The dataset comprised 511 subjects from 15 clinical trials who received ≥1 dose of selumetinib and provided ≥1 measurable postdose concentration of selumetinib and N-desmethyl selumetinib. A 2-compartment model with sequential 0- and 1st-order delayed absorption and 1st-order elimination adequately described selumetinib PK characteristics. A 1-compartment model reasonably described N-desmethyl selumetinib PK characteristics over time simultaneously with selumetinib. Selumetinib geometric mean area under the concentration-time curve ratio (1-sided 90% confidence interval [CI] lower bound) was 76.9% (73.3%) with a low-fat meal and 79.3% (76.3%) with a high-fat meal versus fasting. The lower bound of the 1-sided 90% CI demonstrated a difference of <30% between fed and fasted states. Considering the flat exposure-response relationship within the dose range (20-30 mg/m2), the observed range of exposure, and the variability in the SPRINT trial, this was not considered clinically relevant.

Conditionally replicative adenovirus as a therapy for malignant peripheral nerve sheath tumors.

Oncolytic adenoviruses (Ads) stand out as a promising strategy for the targeted infection and lysis of tumor cells, with well-established clinical utility across various malignancies. This study delves into the therapeutic potential of oncolytic Ads in the context of neurofibromatosis type 1 (NF1)-associated malignant peripheral nerve sheath tumors (MPNSTs). Specifically, we evaluate conditionally replicative adenoviruses (CRAds) driven by the cyclooxygenase 2 (COX2) promoter, as selective agents against MPNSTs, demonstrating their preferential targeting of MPNST cells compared with non-malignant Schwann cell control. COX2-driven CRAds, particularly those with modified fiber-knobs exhibit superior binding affinity toward MPNST cells and demonstrate efficient and preferential replication and lysis of MPNST cells, with minimal impact on non-malignant control cells. In vivo experiments involving intratumoral CRAd injections in immunocompromised mice with human MPNST xenografts significantly extend survival and reduce tumor growth rate compared with controls. Moreover, in immunocompetent mouse models with MPNST-like allografts, CRAd injections induce a robust infiltration of CD8+ T cells into the tumor microenvironment (TME), indicating the potential to promote a pro-inflammatory response. These findings underscore oncolytic Ads as promising, selective, and minimally toxic agents for MPNST therapy, warranting further exploration.

RASopathies influences on neuroanatomical variation in children.

BACKGROUND: RASopathies are a group of disorders characterized by pathogenic mutations in the Ras-mitogen-activated protein kinase (Ras/MAPK) signaling pathway. Distinct pathogenic variants in genes encoding proteins in the Ras/MAPK pathway cause Noonan syndrome (NS) and neurofibromatosis type 1 (NF1), which are associated with increased risk for autism spectrum disorder (ASD) and attention deficit and hyperactivity disorder (ADHD). METHODS: This study examines the effect RASopathies (NS and NF1) has on human neuroanatomy, specifically on surface area (SA), cortical thickness (CT), and subcortical volumes. We compared structural T1-weighted images, using vertex-based analysis for cortical measures and Desikan ROI parcellation for subcortical volumes on children with RASopathies (n=91, mean age = 8.81, SD = 2.12) to sex- and age-matched TD (n=74, mean age=9.07, SD = 1.77). RESULTS: Compared to TD, RASopathies had convergent effects on SA and CT, exhibiting increased SA in the precentral gyrus, decreased SA in occipital regions, and thinner CT in the precentral gyrus. RASopathies exhibit divergent effects on subcortical volumes, with syndrome-specific influences from NS and NF1. Overall children with NS display decreased volumes in striatal and thalamic structures and children with NF1 display increased volumes in the hippocampus, amygdala, and thalamus. CONCLUSIONS: Our study reveals the converging and diverging neuroanatomical effects of RASopathies on human neurodevelopment. The convergence of cortical effects on SA and CT indicates a shared influence of Ras/MAPK hyperactivation on the human brain. Therefore, considering these measures as objective outcome indicators for targeted treatments is imperative.

Autism spectrum disorder profiles in RASopathies: A systematic review.

BACKGROUND: RASopathies are associated with an increased risk of autism spectrum disorder (ASD). For neurofibromatosis type 1 (NF1) there is ample evidence for this increased risk, while for other RASopathies this association has been studied less. No specific ASD profile has been delineated so far for RASopathies or a specific RASopathy individually. METHODS: We conducted a systematic review to investigate whether a specific RASopathy is associated with a specific ASD profile, or if RASopathies altogether have a distinct ASD profile compared to idiopathic ASD (iASD). We searched PubMed, Web of Science, and Open Grey for data about ASD features in RASopathies and potential modifiers. RESULTS: We included 41 articles on ASD features in NF1, Noonan syndrome (NS), Costello syndrome (CS), and cardio-facio-cutaneous syndrome (CFC). Individuals with NF1, NS, CS, and CFC on average have higher ASD symptomatology than healthy controls and unaffected siblings, though less than people with iASD. There is insufficient evidence for a distinct ASD phenotype in RASopathies compared to iASD or when RASopathies are compared with each other. We identified several potentially modifying factors of ASD symptoms in RASopathies. CONCLUSIONS: Our systematic review found no convincing evidence for a specific ASD profile in RASopathies compared to iASD, or in a specific RASopathy compared to other RASopathies. However, we identified important limitations in the research literature which may also account for this result. These limitations are discussed and recommendations for future research are formulated.

The Lack of Ad Hoc Neuropsychological Assessment in Adults with Neurofibromatosis: A Systematic Review.

Background: Neurofibromatosis Type 1 (NF1) is a genetic autosomal dominant disorder that affects both the central and peripheral nervous systems. Children and adolescents with NF1 commonly experience neuropsychological, motor, and behavioral deficits. The cognitive profile hallmark of this disorder includes visuospatial and executive function impairments. These cognitive disorders may persist into adulthood. This study aims to analyze previous research studies that have described cognitive dysfunctions in adults with NF1. The purpose of this analysis is to review the neuropsychological and psychological assessment methods used. Methods: A total of 327 articles were identified based on the search terms in their titles and abstracts. The evaluation was conducted by scrutinizing each article's title, abstract, and text. Results: Only 16 articles were found to be eligible for inclusion based on the pre-defined criteria. The selected studies primarily focus on the development of diagnostic protocols for individuals with NF1. Conclusions: The management of NF1 disease requires a multidisciplinary approach to address symptoms, preserve neurological functions, and ensure the best possible quality of life. However, cognitive impairment can negatively affect psychological well-being. This study suggested that cognitive functions in NF1 patients were not tested using specific measures, but rather were evaluated through intelligence scales. Additionally, the findings revealed that there is no standardized neuropsychological assessment for adults with NF1. To address this gap, it would be helpful to create a specific neuropsychological battery to study cognitive function in NF1 patients during clinical studies. This battery could also serve as a tool to design models for cognitive rehabilitation by using reliable and sensitive measures of cognitive outcomes.

Discrimination of benign, atypical, and malignant peripheral nerve sheath tumors in neurofibromatosis type 1 using diffusion-weighted MRI.

Background: Neurofibromatosis type 1 (NF1) is associated with the development of benign (BPNST) and malignant (MPNST) peripheral nerve sheath tumors. Recently described atypical neurofibromas (ANF) are considered pre-malignant precursor lesions to MPNSTs. Previous studies indicate that diffusion-weighted magnetic resonance imaging (DW-MRI) can reliably discriminate MPNSTs from BPNSTs. We therefore investigated the diagnostic accuracy of DW-MRI for the discrimination of benign, atypical, and malignant peripheral nerve sheath tumors. Methods: In this prospective explorative single-center phase II diagnostic study, 44 NF1 patients (23 male; 30.1 ±â€…11.8 years) underwent DW-MRI (b-values 0-800 s/mm²) at 3T. Two radiologists independently assessed mean and minimum apparent diffusion coefficients (ADCmean/min) in areas of largest tumor diameters and ADCdark in areas of lowest signal intensity by manual contouring of the tumor margins of 60 BPNSTs, 13 ANFs, and 21 MPNSTs. Follow-up of ≥ 24 months (BPNSTs) or histopathological evaluation (ANFs + MPNSTs) served as diagnostic reference standard. Diagnostic ADC-based cut-off values for discrimination of the three tumor groups were chosen to yield the highest possible specificity while maintaining a clinically acceptable sensitivity. Results: ADC values of pre-malignant ANFs clustered between BPNSTs and MPNSTs. Best BPNST vs. ANF + MPNST discrimination was obtained using ADCdark at a cut-off value of 1.6 × 10-3 mm2/s (85.3% sensitivity, 93.3% specificity), corresponding to an AUC of 94.3% (95% confidence interval: 85.2-98.0). Regarding BPNST + ANF vs. MPNST, best discrimination was obtained using an ADCdark cut-off value of 1.4 × 10-3 mm2/s (83.3% sensitivity, 94.5% specificity). Conclusions: DW-MRI using ADCdark allows specific and noninvasive discrimination of benign, atypical, and malignant nerve sheath tumors in NF1.

Pilot study of the effectiveness of a telehealth group for improving peer relationships for adolescents with neurofibromatosis type 1.

BACKGROUND: Interventions for social difficulties have not been investigated in the neurofibromatosis type 1 (NF1) population despite observations of elevated rates of social difficulties. In this pilot study, the effectiveness of a 14-week telehealth PEERS® intervention with nineteen adolescents with NF1 (Mage=13.79 years, SD = 1.32) with social skills difficulties was examined. Measures of social outcomes were completed at three timepoints (before, immediately after, and at 14-week follow-up). RESULTS: Caregiver-reported social-emotional skills, social impairment, caregiver-reported number of adolescent get-togethers, and teen social knowledge showed significant improvement following the intervention. CONCLUSIONS: The PEERS® intervention is promising to support the social and friendship skills of adolescents with NF1 who have social difficulties.

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.

Epidemiology and Outcomes of Neurofibromatosis Type 1 (NF-1): Multicenter Tertiary Experience.

Purpose: The aim of this manuscript was to assess the epidemiology and clinical features of Neurofibromatosis type 1 (NF-1) based on the newly published revised NF-1 diagnostic criteria and to evaluate complications of NF-1 including neurodevelopmental disorders. Patients and methods: A retrospective cross-sectional observational study was conducted in the Ministry of National Guard Health Affairs (MNGHA) healthcare organization branches including four tertiary hospitals and 51 primary health care centers in different regions in Saudi Arabia. This study included all patients diagnosed with NF1 using the revised NIH diagnostic criteria published in 2021 that were registered at the electronic medical records (EMR) from 2015 to 2021. Results: A total of 184 patients fulfilled the diagnostic criteria and were included in this study. The median age at diagnosis was 11 years (IQR: 4.00-20.25). The most encountered diagnostic criteria in this study were Café-au-lait macules (85.3%), and (42.9%) were found to have two or more neurofibromas with plexiform neurofibroma being the most common subtype (23.36%), approximately (36.4%) of the patient with optic pathway glioma. Nearby (26.6%) of the patients displayed different type of tumors. Iris Lisch nodules were presented in 36.4% of patients at a median age of 12 years (IQR: 9.0-21.8). Cardiovascular abnormality was encountered in 9.8% of the patients. Around 27.7% of the patients reported headache and 11.4% of the patient suffered from different type of epilepsy. Besides, 10.5% of the patients had intellectual disability, 33.8% suffered from communication disorders, and 4.9% patients had ADHD. Conclusion: The results of this study will enable practitioners to adopt a more holistic approach and prioritize numerous attributes, which they can subsequently incorporate into their therapeutic methodologies. Furthermore, the identification of these attributes will facilitate an expeditious and accurate diagnosis. Hence, the implementation of intervention during its nascent phase may result in a more advantageous consequence.

Dermatologic Effects of Selumetinib in Pediatric Patients with Neurofibromatosis Type 1: Clinical Challenges and Therapeutic Management.

Background: Plexiform neurofibromas (pNFs) are benign neoplasms, primarily originating from Schwann cells, posing challenges in patients with type 1 neurofibromatosis (NF1) due to pain, disfigurement, compression of vital structures and potential for malignancy. Selumetinib, a MEK1/2 inhibitor, has shown promising results in treating inoperable pNFs, with clinical trials demonstrating tumor volume reduction and improved patient-reported outcomes. Despite its efficacy, dermatologic toxicities may impact the quality of life and treatment adherence. Evaluating the frequency and spectrum of such effects is crucial for effective management. Methods: In a four-year retrospective and prospective study, pediatric NF1 patients with symptomatic, inoperable plexiform neurofibromas (pNFs) were treated with selumetinib. Eligibility criteria included significant morbidity, pNF size exceeding 3 cm or surgical inoperability, and performance status >70%. Hematological, liver, lung and cardiac assessments established baseline health. Selumetinib, orally administered at 25 mg/m2 twice, was administered for two years unless a response warranting extension occurred. Cutaneous AEs were documented and graded by severity according to CTCAE v5.0, with evaluations every three to six months. The impact on symptoms and pNF size was systematically recorded, and biopsies characterized histopathological features in those patients requiring surgery. Results: Twenty patients were enrolled, with an average age at therapy initiation of 11.6 years. Cutaneous side effects were common, with all patients experiencing at least one and a median of two per patient. Xerosis, paronychia and acneiform rash were prevalent. Notably, pre-pubertal individuals were more susceptible to xerosis. Acneiform rash had a higher incidence in older patients and those with skin phototypes II and III. Successful management involved tailored approaches, such as clindamycin for acneiform rash and topical agents for paronychia. Hair abnormalities, including color changes and thinning, occurred, with female patients at higher risk for the latter. Paronychia presented challenges, necessitating various interventions, including surgical approaches. AEs led to treatment suspension in 20% of patients, with tumor rebound observed in 75%. Conclusions: According to our experience, successful management of selumetinib-induced cutaneous AEs requires tailored strategies including surgery. AEs might indirectly determine pNF regrowth due to therapy suspension. We thus emphasize the pivotal role of addressing cutaneous reactions for effective selumetinib management in pediatric patients.

Silver Nanoparticles Selectively Treat Neurofibromatosis Type 1-Associated Plexiform Neurofibroma Cells at Doses That Do Not Affect Patient-Matched Schwann Cells.

Neurofibromatosis Type 1 (NF1) is a common neurogenic condition characterized by heterozygous loss of function mutations in the neurofibromin gene. NF1 patients are susceptible to the development of neurofibromas, including plexiform neurofibromas (pNFs), which occurs in about half of all cases. Plexiform neurofibroma are benign peripheral nerve sheath tumors originating from Schwann cells after complete loss of neurofibromin; they can be debilitating and also transform into deadly malignant peripheral nerve sheath tumors (MPNSTs). Here, our data indicates that silver nanoparticles (AgNPs) may be useful in the treatment of pNFs. We assessed the cytotoxicity of AgNPs using pNF cells and Schwann cells derived from the same NF1 patient. We found that AgNPs are selectively cytotoxic to pNF cells relative to isogenic Schwann cells. We then examined the role of neurofibromin expression on AgNP-mediated cytotoxicity; restoration of neurofibromin expression in pNF cells decreased sensitivity to AgNP, and knockdown of neurofibromin in isogenic Schwann cells increased sensitivity to AgNP, outlining a correlation between neurofibromin expression and AgNP-mediated cytotoxicity. AgNP was able to selectively remove pNF cells from a co-culture with patient-matched Schwann cells. Therefore, AgNPs represent a new approach for clinical management of NF1-associated pNF to address significant clinical need.

Robotic resection for splenic artery aneurysm associated with neurofibromatosis type 1: a case report.

BACKGROUND: Neurofibromatosis type 1 is an autosomal-dominant disease characterized by café-au-lait spots and neurofibromas, as well as various other symptoms in the bones, eyes, and nervous system. Due to its connection with vascular fragility, neurofibromatosis type 1 has been reported to be associated with vascular lesions, such as aneurysms. However, there have been few reports of abdominal visceral aneurysms associated with neurofibromatosis type 1. Furthermore, there have been no reports of robotic treatment of aneurysms associated with neurofibromatosis type 1. In this report, we describe the case of a patient with neurofibromatosis type 1 with a splenic artery aneurysm who was successfully treated with robotic surgery. CASE PRESENTATION: This report describes a 41-year-old Asian woman with a history of neurofibromatosis type 1 who was referred to our hospital for evaluation of a 28 mm splenic artery aneurysm observed on abdominal ultrasound. The aneurysm was in the splenic hilum, and transcatheter arterial embolization was attempted; however, this was difficult due to the tortuosity of the splenic artery. Thus, we suggested minimally invasive robotic surgery for treatment and resection of the splenic artery aneurysm with preservation of the spleen. The postoperative course was uneventful, and the patient was discharged on the eighth day after surgery. At 1 year of follow-up, the patient was doing well, with no evidence of recurrence. CONCLUSION: We encountered a rare case of splenic artery aneurysm in a patient with neurofibromatosis type 1 who was successfully treated with robotic surgery. There is no consensus on treatment modalities for neurofibromatosis-related aneurysms, and endovascular treatment is considered safe and effective; however, surgery remains an important treatment modality. Especially in patients with stable hemodynamic status, robotic surgery may be considered as definitive treatment. To our knowledge, this is the first successfully treated case of a splenic artery aneurysm in a patient with neurofibromatosis type 1.

Correlation between large rearrangements and patient phenotypes in NF1 deletion syndrome: an update and review.

About 5-10% of neurofibromatosis type 1 (NF1) patients exhibit large genomic germline deletions that remove the NF1 gene and its flanking regions. The most frequent NF1 large deletion is 1.4 Mb, resulting from homologous recombination between two low copy repeats. This "type-1" deletion is associated with a severe clinical phenotype in NF1 patients, with several phenotypic manifestations including learning disability, a much earlier development of cutaneous neurofibromas, an increased tumour risk, and cardiovascular malformations. NF1 adjacent co-deleted genes could act as modifier loci for the specific clinical manifestations observed in deleted NF1 patients. Furthermore, other genetic modifiers (such as CNVs) not located at the NF1 locus could also modulate the phenotype observed in patients with large deletions. In this study, we analysed 22 NF1 deletion patients by genome-wide array-CGH with the aim (1) to correlate deletion length to observed phenotypic features and their severity in NF1 deletion syndrome, and (2) to identify whether the deletion phenotype could also be modulated by copy number variations elsewhere in the genome. We then review the role of co-deleted genes in the 1.4 Mb interval of type-1 deletions, and their possible implication in the main clinical features observed in this high-risk group of NF1 patients.

The NF1+/- Immune Microenvironment: Dueling Roles in Neurofibroma Development and Malignant Transformation.

Neurofibromatosis type 1 (NF1) is a common genetic disorder resulting in the development of both benign and malignant tumors of the peripheral nervous system. NF1 is caused by germline pathogenic variants or deletions of the NF1 tumor suppressor gene, which encodes the protein neurofibromin that functions as negative regulator of p21 RAS. Loss of NF1 heterozygosity in Schwann cells (SCs), the cells of origin for these nerve sheath-derived tumors, leads to the formation of plexiform neurofibromas (PNF)-benign yet complex neoplasms involving multiple nerve fascicles and comprised of a myriad of infiltrating stromal and immune cells. PNF development and progression are shaped by dynamic interactions between SCs and immune cells, including mast cells, macrophages, and T cells. In this review, we explore the current state of the field and critical knowledge gaps regarding the role of NF1(Nf1) haploinsufficiency on immune cell function, as well as the putative impact of Schwann cell lineage states on immune cell recruitment and function within the tumor field. Furthermore, we review emerging evidence suggesting a dueling role of Nf1+/- immune cells along the neurofibroma to MPNST continuum, on one hand propitiating PNF initiation, while on the other, potentially impeding the malignant transformation of plexiform and atypical neurofibroma precursor lesions. Finally, we underscore the potential implications of these discoveries and advocate for further research directed at illuminating the contributions of various immune cells subsets in discrete stages of tumor initiation, progression, and malignant transformation to facilitate the discovery and translation of innovative diagnostic and therapeutic approaches to transform risk-adapted care.

The PlexiQoL, a patient-reported outcome measure on quality of life in neurofibromatosis type 1-associated plexiform neurofibroma: translation, cultural adaptation and validation into the Dutch language for the Netherlands.

BACKGROUND: Half of the patients with Neurofibromatosis type 1 (NF1) develop one or more tumours called plexiform neurofibromas, which can have a significant impact on Quality of Life (QoL). The PlexiQoL questionnaire is a disease-specific QoL measure for adults with NF1-associated plexiform neurofibromas. The aim of this study was to adapt and validate a Dutch version of the PlexiQoL for the Netherlands. METHODS: The PlexiQoL was translated using the dual-panel methodology, followed by cognitive debriefing interviews to assess face and content validity. The psychometric properties were evaluated by administering the questionnaire on two separate occasions to a sample of adults with NF1 and plexiform neurofibromas. Feasibility was evaluated by the presence of floor/ceiling effects. Reliability was assessed by evaluating Cronbach's alpha coefficient and test-retest reliability, using Spearman's rank correlation coefficients. Mann-Whitney U tests were used to check for known group validity. The Nottingham Health Profile (NHP) questionnaire was used as comparator questionnaire to evaluate convergent validity. RESULTS: The translation and cognitive debriefing interviews resulted in a Dutch version of the PlexiQoL that reflected the original concept and underlying semantic meanings of the UK English version. Forty participants completed the validation survey. The Dutch PlexiQoL demonstrated excellent internal consistency (Cronbach's α 0.825) and test-retest reliability (Spearman correlation coefficient 0.928). The questionnaire detected differences in PlexiQoL scores between participants based on self-reported general health and disease severity. Convergent validity was confirmed for relevant NHP subsections. CONCLUSIONS: The Dutch PlexiQoL demonstrated excellent psychometric properties and can be reliably used to measure plexiform neurofibroma-related QoL in adults with NF1 in the Netherlands.