Search Results (241)

Background: In decentralized clinical trials, some or all activities occur outside of traditional sites, which may reduce time away from school/work and decrease participation burden for patients and their parents/caregivers. This methodology may improve recruitment and retention in studies, which is important for rare diseases like neurofibromatosis type 1 (NF1) and schwannomatosis (SWN). Published guidance exists for the general conduct of decentralized trials, but specific considerations for clinical trial design and endpoints in NF1/SWN have not yet been explored. Methods: The Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration is a group of researchers, clinicians, and people affected by NF1 and SWN whose shared goal is to advance clinical trial methodology for NF1/SWN. In December 2023, REiNS members met to discuss the opportunities and challenges of conducting NF1/SWN decentralized trials. Results: Endpoints that are promising for use in NF1/SWN decentralized trials include visual acuity (as tested by the computerized amblyopia treatment study HOTV testing algorithm); electronic versions of REiNS-recommended patient reported outcome measures; digital health technologies for functional outcomes; radiography and computed tomography scans for imaging outcomes; remote photography to assess cutaneous neurofibromas; “e-centralized” evaluations of neurocognitive functioning; and remote biomarkers collected with analyte stabilizing tubes and self-collection devices. Conclusions: Further research is necessary to validate endpoints for decentralized trials for NF1/SWN and evaluate their feasibility. However, trial designs that incorporate decentralized elements hold considerable promise for rare diseases like NF1/SWN where patients encounter significant barriers to traditional clinical trial participation. Full article

Background: This study applies Buysse’s sleep health framework to examine sleep in children and adolescents with neurofibromatosis type 1 (NF1). By examining sleep timing, daytime sleepiness, sleep quality, sleep behavior, sleep duration, and sleep efficiency together, this framework captures the multidimensional nature of sleep and its relationship with biopsychosocial factors and health-related quality of life (HR-QoL) in NF1. Methods: This multi-site, prospective, cross-sectional study included 131 children and adolescents with NF1 and 71 typically developing (TD) controls aged 6 to 16 years. A sleep health composite was derived from carer rating scales and 7 days of actigraphy. A biopsychosocial framework was used to examine factors associated with sleep health in NF1, including sociodemographic, cognitive, psychopathology, and biological variables. Independent predictors of QoL were examined to assess the unique contributions of sleep quality, sleep duration, and previously established predictors of HR-QoL in NF1. Results: Poorer sleep health was evident in children with NF1. Compared with TD controls, children with NF1 were five times as likely to have poor sleep quality, with almost 78% demonstrating impaired sleep efficiency and nearly half not obtaining sufficient sleep at night. The strongest risk factors were being male, elevated pain, and having greater levels of ADHD and autism spectrum disorder traits. Conclusions: Findings suggest sleep health in NF1 is interconnected with multiple biopsychosocial factors. A better understanding of these relationships will help identify early risk markers, improve prediction of clinical trajectories, and guide the development of targeted multimodal interventions for sleep disruption in NF1. Full article

Background/Objectives: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder caused by pathogenic variants in the NF1 gene, characterized by high phenotypic variability. Methods: We present clinical and molecular data from a Romanian cohort of 54 patients initially diagnosed clinically. Results: Phenotypic evaluation (n = 54) revealed a high prevalence of café-au-lait macules (100%), Lisch nodules (64.8%), axillary/inguinal freckling (61.1%), and cutaneous neurofibromas (42.6%). Due to financial constraints (genetic testing not covered by the national health system), molecular confirmation by next-generation sequencing (NGS) was possible in only 12 patients (mostly sporadic cases and young children). Genetic testing identified a diverse spectrum of variants, including frameshift (41.7%, n = 5), nonsense (33.3%, n = 4), missense (16.7%, n = 2), and one splicing deletion (8.3%, n = 1). A novel complex NF1 frameshift variant, c.7504_7508delinsC (p.Ser2502Argfs*24) in exon 54, was identified in a patient exhibiting an aggressive phenotype characterized by plexiform neurofibromas, a malignant peripheral nerve sheath tumor (MPNST), and severe skeletal abnormalities. Additionally, a recurrent nonsense variant, NF1 c.910C>T (p.Arg304*), was detected in two unrelated individuals. Conclusions: The high proportion of sporadic cases (58.3%) in the molecularly tested subgroup underscores the critical role of early genetic screening. By integrating clinical data from 54 patients with the first molecular characterization of NF1 in Romania, this study expands the mutational spectrum and provides preliminary, descriptive insights into genotype–phenotype correlations. It also proposes a cost-effective diagnostic algorithm adapted for resource limited settings and lays the groundwork for future multicenter initiatives. Given the exploratory nature of the molecular subgroup (n = 12), all genotype–phenotype observations require validation in larger independent cohorts. Full article

Background/Objectives: NF1 encodes neurofibromin, a RAS-GTPase-activating protein (GAP), and heterozygous loss-of-function variants cause neurofibromatosis type 1. Missense variants outside the GAP-related domain (GRD) are difficult to classify because supporting functional evidence is limited. NF1 c.6394T>C (p.Ser2132Pro) is currently listed in ClinVar as a variant of uncertain significance. We examined its functional consequences and evaluated whether the resulting evidence supports a likely pathogenic interpretation under the ACMG/AMP framework. Methods: We evaluated p.Ser2132Pro using population databases, evolutionary conservation, calibrated in silico predictors, and structural mapping onto the full-length cryo-EM model of neurofibromin. The variant was then introduced at the endogenous NF1 locus in HEK293T and A375 cells by prime editing, and we measured neurofibromin abundance, transcript levels, RAS-GTP dynamics, and MAPK pathway reactivation after PLX4032 treatment. Evidence was integrated under the ACMG/AMP framework. Results: p.Ser2132Pro was absent from population databases, affected a highly conserved residue buried within the C-terminal HEAT domain, and received concordant deleterious predictions from calibrated in silico tools. At the endogenous locus, p.Ser2132Pro reduced neurofibromin abundance by 88–95% in both cell models while NF1 transcript levels were only modestly reduced, impaired RAS-GTP signal termination, doubled steady-state RAS-GTP in A375 cells, and produced 5-fold higher ERK phosphorylation than the non-targeting control under PLX4032 treatment. Conclusions: These findings support a cellular loss-of-function effect of p.Ser2132Pro characterized primarily by reduced neurofibromin abundance with impaired neurofibromin-dependent RAS regulation. Under a conservative ACMG/AMP interpretation, the combined evidence supports a Likely Pathogenic interpretation of NF1 c.6394T>C (p.Ser2132Pro). Full article

Background: Neurocutaneous syndromes (NCS), including neurofibromatosis type 1 (NF1), tuberous sclerosis complex (TSC), and Sturge–Weber syndrome (SWS), are rare neurodevelopmental disorders frequently associated with epilepsy, cognitive impairment, and behavioural difficulties. Although caused by different genetic alterations, these disorders share biological mechanisms that influence brain development, neuronal connectivity, and network excitability. Beyond being a common neurological manifestation, epilepsy is increasingly recognized as an important factor influencing cognitive and behavioural outcomes in neurocutaneous syndromes. Methods: This narrative review summarizes current evidence on the relationship between epilepsy, cognitive dysfunction, and behavioural manifestations in major neurocutaneous syndromes. Attention is given to epileptogenic mechanisms, shared molecular pathways, and factors influencing long-term neurodevelopmental outcomes. Results: Epilepsy is consistently associated with cognitive and behavioural outcomes in neurocutaneous syndromes, particularly in disorders characterized by early-onset and treatment-resistant seizures. Early seizure onset, poor seizure control, and persistent network dysfunction have been associated with intellectual disability, executive dysfunction, attention deficits, autism spectrum features, and impaired adaptive functioning. In TSC and SWS, epilepsy burden is strongly associated with cognitive outcome, particularly in interaction with underlying structural, vascular, and molecular abnormalities. In neurofibromatosis type 1, cognitive and behavioural difficulties are more often related to altered neuronal connectivity and dysregulated signalling pathways, although epilepsy may further contribute to neurodevelopmental impairment in a subset of patients. Despite their distinct genetic origins, these disorders converge on dysregulated RAS/MAPK, PI3K/AKT/mTOR, and Gαq-mediated signalling pathways that influence both epileptogenesis and brain development. Conclusions: Despite their distinct genetic origins, major neurocutaneous syndromes converge on common pathways linking epilepsy, network dysfunction, and neurodevelopmental impairment. Understanding how these processes interact may facilitate earlier intervention and more accurate prognostic assessment, ultimately improving long-term outcomes for affected children. Full article

Neurofibromatosis type 1 (NF1) is a genetic tumor predisposition syndrome characterized by a substantial risk of developing peripheral nerve sheath tumors, including malignant peripheral nerve sheath tumors (MPNSTs), which occur in 8–13% of patients. Approximately 50% arise from plexiform neurofibromas (PNs) and 40% develop de novo, making them a major cause of premature mortality. Current clinical management is limited by the intrinsic shortcomings of standard imaging modalities: magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT), and tissue biopsy in distinguishing benign PNs from early malignant transformation, which remains a major clinical challenge. This progression follows a stepwise molecular continuum marked by cumulative genetic alterations and widespread epigenetic dysregulation. In this setting, liquid biopsy has emerged as a promising non-invasive approach to help fill these diagnostic gaps by enabling real-time molecular monitoring through the analysis of circulating tumor DNA (ctDNA) and other blood-based biomarkers. This review examines the current evidence supporting liquid biopsy applications in NF1 management, including early detection of MPNST, discrimination between benign and malignant lesions, mutational profiling for therapeutic targeting, and disease monitoring before and during treatment. We also discuss the current evidence on fragmentomics, methylomics and driver mutation profiling as tools to distinguish PNs from MPNSTs. Recent evidence suggests that liquid biopsy may help detect molecular changes associated with malignant transformation before clear clinical signs emerge, potentially opening an important window for intervention and supporting a shift towards a more molecularly informed surveillance model. Finally, this review considers the possible extension of liquid biopsy to other tumor types, including NF1-deficient breast cancer, and outlines a future management framework aimed at improving early diagnosis and personalized therapeutic intervention in this high-risk population. Full article

Ultrasonography can assist in the preoperative evaluation and postoperative surveillance of superficial soft tissue tumors of the hand. We present an ultrasound-based identification of a neurofibroma in a patient with neurofibromatosis type 1 (NF1). A 45-year-old male presented with a slowly enlarging subcutaneous mass over the dorsal aspect of the hand associated with localized paresthesia. Physical examination revealed characteristic NF1 stigmata, including café-au-lait macules, axillary freckling, and craniofacial asymmetry suggestive of sphenoid wing dysplasia. High-resolution ultrasonography demonstrated a well-defined hypoechoic fusiform lesion along the course of a digital nerve, suggestive of a peripheral nerve sheath tumor. Magnetic resonance imaging showed a T2-hyperintense lesion compatible with a nerve sheath tumor. Surgical excision was subsequently performed, and histopathological examination confirmed a localized neurofibroma with incorporation of native nerve fascicles within a myxoid spindle cell matrix. Serial postoperative ultrasonography at 3 and 12 months demonstrated no evidence of local recurrence. This case highlights ultrasonography as a practical, radiation-free, and cost-effective modality for both preoperative assessment and longitudinal follow-up of superficial NF1-associated neurofibromas. Full article

Juvenile myelomonocytic leukemia (JMML) is a rare, aggressive myeloproliferative neoplasm of early childhood characterized by constitutive activation of the RAS-MAPK signaling pathway. RASopathies are a heterogeneous group of complex genetic disorders arising from germline mutations that dysregulate RAS-MAPK signaling. Noonan syndrome, CBL syndrome, and neurofibromatosis type 1 (NF1) are the three major RASopathies predisposing to JMML. More than 90% of JMML cases harbor germline or somatic mutations in one of five canonical driver genes—PTPN11, NRAS, KRAS, NF1, or CBL—establishing JMML as the prototypical malignant manifestation of RASopathy biology. The fifth edition of the World Health Organization Classification of Tumours reclassified JMML as a myeloproliferative neoplasm while the International Consensus Classification adopted JMML under pediatric and/or germline mutation-associated disorders, introducing a JMML-like category for cases lacking five canonical mutations but harboring emerging drivers such as SH2B3::LNK alterations and ALK::ROS1 fusions. The distinction between germline and somatic mutations profoundly influences prognosis: e.g., germline PTPN11-associated myeloproliferations and many germline CBL cases undergo spontaneous resolution, whereas somatic PTPN11- and NF1-mutated JMML is more aggressive and requires prompt allogeneic hematopoietic stem cell transplantation. DNA methylation profiling has emerged as the most robust prognostic framework, with consensus defining high-, intermediate-, and low-methylation subgroups that independently predict outcome. Both genotype and DNA methylation subclassification have been integrated into clinical decision-making, incorporating pretransplant azacitidine, watch-and-wait approaches for favorable-risk patients, and emerging targeted therapies including MEK inhibitors. This review synthesizes recent advances in understanding JMML as a bona fide RASopathy; provides a diagnostic algorithm, molecular landscapes, and prognostic models; and highlights opportunities for molecularly targeted therapeutic intervention. Full article

Moyamoya angiopathy (MMA) is a rare, chronic progressive cerebrovascular condition characterized by bilateral stenosis or occlusion of the terminal internal carotid arteries and their major branches. This progressive occlusion triggers the development of telangiectatic and fragile vessels at the base of the brain, creating the characteristic angiographic appearance of a “puff of smoke.” Depending on the etiology, MMA is classified as Moyamoya Disease (MMD) when idiopathic and primary or Moyamoya Syndrome (MMS) when associated with underlying systemic conditions. While the RNF213 gene, particularly the p.R4810K variant, is recognized as the major susceptibility locus for MMD in East Asian populations, it does not fully account for the global genetic landscape or the phenotypic diversity of the disease. This review provides a comprehensive overview of the genetic architecture of the entire MMA spectrum, exploring loci beyond RNF213. We analyze the role of genes involved in vascular smooth muscle cell contractility (ACTA2, MYH11), TGF-β signaling, and DNA repair mechanisms that drive MMS, alongside the genetic basis of syndromic forms associated with neurofibromatosis type 1, trisomy 21, and RASopathies. Understanding these diverse genetic drivers is crucial for early diagnosis, risk stratification, and the development of targeted molecular therapies. Full article

Plexiform neurofibromas (pNF1s) are benign peripheral nerve sheath tumors caused by NF1 loss, leading to dysregulated RAS/mitogen-activated protein kinase (MAPK) signaling. While the mitogen-activated protein kinase kinase (MEK) inhibitors, selumetinib and mirdametinib, can reduce tumor volume, surgical resection remains the primary treatment for immediate debulking and symptom relief. Complete removal is often limited by tumor infiltration along nerve plexuses, and residual tumors may undergo postsurgical tissue remodeling, producing localized regions of stiffened extracellular matrix (ECM). The impact of ECM stiffness on pNF1 growth and drug responses remains unclear. Using immortalized patient-derived pNF1 tumor cell lines cultured in 3D hydrogels with defined stiffness (1.5 kPa, soft; 7 kPa, stiff), we found that stiff ECM promoted spread morphology, increased growth, and progressive intracellular softening. Stiff ECM also reduced lysyl oxidase (LOX) expression, suggesting mechanoadaptive ECM remodeling, and increased P-glycoprotein expression. Under the same conditions, stiff ECM was associated with reduced sensitivity to selumetinib. These results provide the first evidence that ECM stiffening, including that plausibly associated with postsurgical remodeling, may contribute to pNF1 growth and reduced sensitivity to selumetinib in this 3D pNF1 culture model. Our findings highlight mechanobiology as a key regulator of tumor behavior and support further investigation of ECM-targeted strategies to improve outcomes in neurofibromatosis type 1 (NF1). Full article

Neurofibromatosis type 1 (NF1) patients are predisposed to develop plexiform neurofibromas (PNFs). By cross-comparison of RNA sequencing and RUNX1-CHIP sequencing data on mouse PNFs, we found that transcripts encoding the NF1-interacting p97/valosin-containing protein (VCP) gene are overexpressed in PNFs. Co-immunoprecipitation confirmed that VCP bounded to neurofibromin. Western blot and immunostaining confirmed VCP overexpression in both mouse and human PNFs. Treatment of primary mouse PNF Schwann cells with CB-5083, a p97/VCP inhibitor, led to accumulation of poly-ubiquitinated proteins and generation of irresolvable proteotoxic stress. Pharmacological or genetic inhibition of VCP reduced mouse PNF cell-derived sphere number, and genetic inhibition of Vcp in Schwann cell precursors decreased tumor-like lesion numbers in a cell transplantation model. In vivo treatment with CB-5083 in Nf1^fl/fl;DhhCre PNF mice significantly inhibited cell proliferation, increased cell apoptosis and reduced PNF volume. The combination with a MEK inhibitor did not increase efficacy compared to the single agent, supporting the hypothesis that VCP functions in parallel to, and may be modulated by, RAS–MAPK signaling under stress or oncogenic conditions. The significant effects of VCP inhibition in this pre-clinical study suggest a potential novel therapy for patients with PNFs. Full article

We describe a case of a 3-year-old girl with neurofibromatosis type 1 presenting with arterial hypertension, in whom multimodal vascular imaging identified significant right renal artery stenosis. The patient was successfully treated with percutaneous transluminal renal angioplasty; however, post-procedural Doppler ultrasound revealed a transient vascular fistula. Changes in renal arterial inflow during the procedure may have temporarily altered pressure gradients, facilitating the opening of communication involving pre-existing compensatory collateral vessels. This case illustrates the diagnostic value of multimodal vascular imaging in pediatric hypertension and highlights a rare, self-limiting post-interventional vascular phenomenon. Full article

Neurofibromatosis type 1 (NF1) and NF2-related schwannomatosis (NF2-SWN) are major genetic tumor predisposition syndromes characterized by progressive, often debilitating neoplasms of the peripheral and central nervous systems. Over the past five years, substantial advances in molecular genetics, signaling biology, and targeted therapeutic development have reshaped diagnostic and management paradigms for both disorders. This Perspective synthesizes recent developments, including gene-based reclassification, emergence of MEK inhibitor therapy in NF1, renewed evaluation of bevacizumab and kinase-pathway inhibitor brigatinib, the discovery of a novel TβR1-RKIP pathogenic axis, and a brain-penetrant HDAC inhibitor in NF2-SWN. These insights highlight a shift toward precision-medicine strategies and mechanistically driven therapies poised to redefine future clinical care. Full article

Background/Objectives: Neurofibromatosis Type 1 (NF1) is a genetic syndrome caused by pathogenic NF1 variants encoding neurofibromin, a Ras GTPase activating protein. Individuals with NF1 develop peripheral nerve sheath tumors called neurofibromas. Approximately 50% of NF1 patients develop plexiform neurofibromas (pNFs) which have up to 13% lifetime risk of transformation into malignant peripheral nerve sheath tumors (MPNSTs). Current therapeutic strategies emphasize surgical resection with wide margins, radiation, and traditional chemotherapy for unresectable MPNSTs. However, NF1 patients diagnosed with MPNSTs have 5-year survival rates as low as 16%. The two recently FDA-approved drugs for pNFs, the MEK inhibitors selumetinib and mirdametinib, are not used to prevent or treat MPNSTs. Methods: The MEK inhibitor trametinib and the dual HDAC/PI3K inhibitor fimepinostat were assessed for growth inhibitory effects in nine unique patient-derived MPNST cell lines, as both drugs have preclinical efficacy in other Schwann cell-derived tumors. Results: Trametinib, which is approved for malignant melanomas, promoted cell death in 7/9 MPNST cell lines with a geometric mean GI50 = 17 nM. When directly compared to selumetinib and mirdametinib in a subset of four MPNST cell lines, trametinib had the lowest mean GI50 (trametinib = 38 nM, mirdametinib = 1.6 µM, selumetinib = 4.9 µM). Trametinib was also superior to selumetinib and mirdametinib in blocking ERK1/2 phosphorylation for 24 h. Fimepinostat promoted cell death in all cell lines with a geometric mean GI50 = 17 pM. Conclusions: These studies demonstrate in vitro efficacy for two candidate MPNST therapeutics which could reduce tumor burden and metastasis in NF1 patients. Full article

Objective: The current study tested (1) how ADHD symptoms and internalizing or externalizing problems covaried across ages 3–18 in children with neurofibromatosis type 1 (NF1), and (2) whether demographic and NF1-specific factors moderated the associations. Method: We analyzed integrated cross-sectional data of 685 observations from 455 children and adolescents with NF1 (M_age = 9.79 years, SD = 3.88; 43% female) across six institutions in the United States and Australia. ADHD symptoms (inattention and hyperactivity/impulsivity) and internalizing/externalizing problems were assessed via parent-report measures. Time-varying effect modeling was employed to examine the age-specific associations between ADHD symptoms and internalizing/externalizing problems. Moderation analyses tested effects of sex, parental education, and NF1 inheritance mode (familial vs. sporadic). Results: Inattention and hyperactivity/impulsivity symptoms were associated with greater internalizing and externalizing problems across ages 3–17. Inattention links were similar across ages, while the hyperactivity/impulsivity-externalizing link was stronger in early childhood than during adolescence. NF1 inheritance mode significantly moderated the inattention-externalizing link, with stronger associations observed among children with familial NF1. Other moderators were nonsignificant. Conclusions: ADHD symptoms are robustly linked to internalizing and externalizing problems from childhood to middle adolescence in children with NF1, with familial NF1 emerging as a potentially elevated risk factor. Future longitudinal and experimental research is needed to inform integrated intervention approaches, especially for those with familial NF1. Full article