Selumetinib for children with neurofibromatosis type 1 and plexiform neurofibromas: A plain language summary of SPRINT.

WHAT IS THIS SUMMARY ABOUT?: This summary describes a publication about a study called SPRINT. The SPRINT study included 50 children with neurofibromatosis type 1 (NF1) and plexiform neurofibroma (PN) that could not be removed with surgery. PNs are tumors that grow along nerves and can cause various problems for children, such as pain, changes to appearance, and muscle weakness. In SPRINT, the study team wanted to learn whether a medication called selumetinib was able to shrink the PN caused by NF1 (also known as NF1-related PN), and if shrinking PNs helped relieve children of the problems caused by it. To assess how selumetinib might help, children had scans to measure the size of their PN, completed questionnaires, and had a variety of other tests done by their doctor. Their caregivers also completed questionnaires about their child. The children took selumetinib capsules twice a day on an empty stomach. WHAT WERE THE RESULTS?: The results showed that selumetinib was able to shrink the PN for most children (68%). The results also showed that the problems caused by the children's PNs mostly improved while on selumetinib treatment. SPRINT also showed that the side effects of selumetinib were mainly mild and could be managed by doctors. WHAT DO THE RESULTS MEAN?: Before SPRINT, there were not many treatment options for children with NF1 and PN as there were no medications that had been shown to shrink PN, and surgery was not always possible. SPRINT showed that this medication shrinks most PNs and could help children with NF1 and PN. In April 2020, selumetinib was approved by the US Food and Drug Administration (FDA) because of the results of SPRINT. Selumetinib was the first and, as of February 2024, is the only medicine that can be prescribed by doctors to help children with NF1-related PN. Clinical Trial Registration: NCT01362803 (SPRINT) (ClinicalTrials.gov).

Generation of heterozygous and homozygous NF1 lines from human-induced pluripotent stem cells using CRISPR/Cas9 to investigate bone defects associated with neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders caused by heterozygous germline NF1 mutations. NF1 affects many systems, including the skeletal system. To date, no curative therapies are available for skeletal manifestations such as scoliosis and tibial dysplasia, mainly due to the lack of knowledge about the mechanisms that underlie this process. By using CRISPR/Cas9-mediated gene editing in human-induced pluripotent stem cells (hiPSCs) to minimize the variability due to genetic background and epigenetic factors, we generated isogenic heterozygous and homozygous NF1-deficient hiPSC lines to investigate the consequences of neurofibromin inactivation on osteoblastic differentiation. Here, we demonstrate that loss of one or both copies of NF1 does not alter the potential of isogenic hiPSCs to differentiate into mesenchymal stem cells (hiPSC-MSCs). However, NF1 (+/-) and NF1 (-/-) hiPSC-MSCs show a defect in osteogenic differentiation and mineralization. In addition, we show that a mono-allelic deletion in NF1 in an isogenic context is sufficient to impair cell differentiation into osteoblasts. Overall, this study highlights the relevance of generating isogenic lines, which may help in genotype-phenotype correlation and provide a human cellular model to understand the molecular mechanisms underlying NF1 and, thus, discover new therapeutic strategies.

Successful revascularization using a saphenous vein for a ruptured brachial artery aneurysm in a patient with neurofibromatosis type I.

Vasculopathy in patients with type 1 neurofibromatosis is known. Brachial artery aneurysms in patients with type 1 neurofibromatosis are rare, but any rupture can be extremely serious. A 56-year-old woman presented to our hospital with sudden pain in her right upper arm. Computed tomography revealed a ruptured brachial artery aneurysm, and operative reconstruction using a saphenous vein graft was performed. This is one of the few case reports of such successful revascularization using saphenous vein. The pathologic findings suggest neurogenic tumor invasion, and end-to-side anastomosis was effective in avoiding hemorrhagic complications.

A Giant Scrotal Neurofibroma in a Child Masquerading as Filariasis: Uncommon Presentation of a Common Disease.

Neurofibroma of the scrotum is a very uncommon benign neoplasm, specifically when it affects teenagers and is not associated with neurofibromatosis type I. To the best of our knowledge, only a couple of cases of neurofibroma in children have been documented. Here, we report a case study of a 17-year-old boy who had a giant scrotal lump for ten years masquerading clinically as filariasis. A provisional diagnosis of benign nerve sheath neoplasm was made based on cytology findings. The lump was surgically removed from the patient, and a histopathological and immunohistochemistry examination established the diagnosis of neurofibroma. The combined clinical, preoperative cytological, histological, and immunohistochemistry findings were not presented in the literature in any of the formerly documented cases of scrotal neurofibroma. The current case expands the spectrum of differential diagnoses for scrotal tumours that clinicians have previously observed.

Inflammatory/juvenile-like polyps in neurofibromatosis type 1 associated with epithelial dysplasia.

The term "juvenile-like (inflammatory/hyperplastic) mucosal polyps" (JLIHMP) has been recently introduced to describe a spectrum of polypoid lesions in patients with neurofibromatosis type 1 (NF-1). Due to the scarce number of reported cases and histopathological similarities with entities such as sporadic/syndromic juvenile polyps or inflammatory fibroid polyps, this entity remains a subject of debate. We describe herein a case of multiple JLIHMPs in a patient with NF-1, and we document the presence of low-grade dysplasia within one of these polyps.

Mandibular Brown Tumor Revealing Hyperparathyroidism in a Patient With Neurofibromatosis Type I: Case Report.

The brown tumor is a non-neoplastic lesion resulting from an abnormality in bone metabolism in the context of primary, secondary, or tertiary hyperparathyroidism. They can affect any bone structure and be single or multiple. They are usually located on the long bones, pelvis, ribs, and collarbones. Facial localization is rare and is found in only 4.5% of brown tumors dominated by mandibular involvement. The treatment of a brown tumor depends on several elements: etiology, location, and symptomatology. It can regress or disappear after the treatment of hyperparathyroidism, thus avoiding surgical removal. Otherwise, excision of this mass is performed. We illustrate through this case a brown mandibular tumor revealing secondary hyperparathyroidism in a patient with a history of end-stage chronic renal failure on hemodialysis and associated neurofibromatosis type 1.

Minimal intervention for neurofibromatosis type I manifestations: A case report.

INTRODUCTION AND IMPORTANCE: Neurofibromatosis type I (NF1, OMIM: 162200) is a benign, autosomal dominant, tumorigenic predisposing syndrome with variable manifestations. Both neurofibromatosis and soft tissue sarcomas are associated with the formation of hematomas. Moreover, skeletal manifestations of NF1 include focal or generalized forms and expansive or infiltrative growth types. CASE PRESENTATION: A 19-year-old NF1 female patient presented with an expanding post-traumatic facial hematoma that resembled a soft-tissue tumor at initial presentation. A congenital neck mass was noted ipsilateral to her craniofacial skeletal deformities. Multiple imaging modalities were used to aid diagnosis, and urgent surgical intervention of the expanding facial lesion was performed. Her neck lesion and skeletal deformities were monitored, and her recovery was uneventful at 1-year follow-up, with no progression. CLINICAL DISCUSSION: A palpable, non-pulsatile soft tissue mass is a common clinical presentation with a diverse differential diagnosis. Despite the low incidence of post-traumatic vascular injuries and lesions in the maxillofacial region, neurofibromatosis-associated vasculopathy remains an underestimated and serious manifestation of NF1. The reported zygomatic arch deformity is believed to be unique. However, the NF1 tumor-associated skeletal malformations are not linearly related. CONCLUSION: NF1 is a multisystem disorder necessitating an early multidisciplinary team approach. Minimal intervention can help convert an emergent operation into an urgent one and preclude the need for major surgery. The case illustrated a rare example of simultaneous affection of soft tissue and jaw bones in NF1 patients.

Deregulated expression of polycomb repressive complex 2 target genes in a NF1 patient with microdeletion generating the RNF135-SUZ12 chimeric gene.

Neurofibromatosis type I (NF1) microdeletion syndrome, accounting for 5-11% of NF1 patients, is caused by the heterozygous deletion of NF1 and a variable number of flanking genes in the 17q11.2 region. This syndrome is characterized by more severe symptoms than those shown by patients with intragenic NF1 mutation and by variable expressivity, which is not fully explained by the haploinsufficiency of the genes included in the deletions. We here reevaluate an 8-year-old NF1 patient, who carries an atypical deletion generating the RNF135-SUZ12 chimeric gene, previously described when he was 3 years old. As the patient has developed multiple cutaneous/subcutaneous neurofibromas over the past 5 years, we hypothesized a role of RNF135-SUZ12 chimeric gene in the onset of the patient's tumor phenotype. Interestingly, SUZ12 is generally lost or disrupted in NF1 microdeletion syndrome and frequently associated to cancer as RNF135. Expression analysis confirmed the presence of the chimeric gene transcript and revealed hypo-expression of five out of the seven analyzed target genes of the polycomb repressive complex 2 (PRC2), to which SUZ12 belongs, in the patient's peripheral blood, indicating a higher transcriptional repression activity mediated by PRC2. Furthermore, decreased expression of tumor suppressor gene TP53, which is targeted by RNF135, was detected. These results suggest that RNF135-SUZ12 chimera may acquire a gain of function, compared with SUZ12 wild type in the PRC2 complex, and a loss of function relative to RNF135 wild type. Both events may have a role in the early onset of the patient's neurofibromas.

The Perceived Influence of Neurofibromatosis Type 1(NF1) on the Parents' Relationship.

Neurofibromatosis type 1 (NF1) is a genetic condition affecting 1 in 3000 individuals. Having a child with a chronic illness can introduce both practical and emotional challenges to a parental relationship. This cross-sectional study was administered to 50 parents of children with NF1, diagnosed between the ages of 1-24. Each participant was provided a 50-item self-report survey to complete during an inpatient or outpatient visit. The survey gathered information on the participants' views of the spouse/partner relationship, coping mechanisms, and elements that supported emotional connections. While the majority of parental relationships were reported to remain strong, the mean relationship quality was perceived to have decreased compared to prior to the child's diagnosis. Compassionate and open communication, shared perspective, having time alone with their partner outside of medical situations, and dyadic coping were identified as strategies that could strengthen the relationship. The identified stressors to the parental relationship during the NF1 illness trajectory can inform interventions and help guide development of a couple's intervention. The National Cancer Institute, NIH Institutional Review Board approved this study (12-C-0206).

Extended Transsphenoidal Approach for Gross Total Resection of Hypothalamic Tumor.

Tumors of the optic pathway and/or hypothalamus are uncommon, and the majority occur in patients with neurofibromatosis type 1.1,2 These lesions can be managed with a "watch-and-wait" approach; however, when treatment is indicated, the optimal strategy is wholly case dependent. We present a 22-year-old female patient with neurofibromatosis type 1 who had a partially cystic mass within the right mamillary body (Video 1). The mass was present on prior imaging but had increased in size and was newly enhancing with evidence of mass effect on the right optic tract. Given her history and the lesion's progression, treatment was recommended. The patient elected for surgery over radiation. Preoperatively, there were no visual field deficits or signs of hypopituitarism. We undertook a unilateral, extended transsphenoidal approach. Additional bony removal of the tuberculum sellae and planum sphenoidale enabled greater exposure of the anterior cranial fossa. The circular sinus was cauterized and divided for visualization of the pituitary stalk and clear identification of the hypothalamus. This provided an operative corridor superior to the pituitary gland and just beneath the optic nerves. The procedure proceeded without complication, and gross total resection was achieved. Postoperative imaging demonstrated gross total resection with a normal-appearing pituitary gland. Of note, the patient did experience mildly elevated postoperative sodium and was treated with desmopressin for transient diabetes insipidus. Twelve- and 24-month follow-up imaging showed no recurrence. The extended transsphenoidal approach used here offers a safe and suitable working corridor to achieve total resection of hypothalamic lesions without injury to the pituitary gland.

Destabilizing NF1 variants act in a dominant negative manner through neurofibromin dimerization.

The majority of pathogenic mutations in the neurofibromatosis type I (NF1) gene reduce total neurofibromin protein expression through premature truncation or microdeletion, but it is less well understood how loss-of-function missense variants drive NF1 disease. We have found that patient variants in codons 844 to 848, which correlate with a severe phenotype, cause protein instability and exert an additional dominant-negative action whereby wild-type neurofibromin also becomes destabilized through protein dimerization. We have used our neurofibromin cryogenic electron microscopy structure to predict and validate other patient variants that act through a similar mechanism. This provides a foundation for understanding genotype-phenotype correlations and has important implications for patient counseling, disease management, and therapeutics.

Estudio clínico y molecular en pacientes cubanos con neurofibromatosis tipo i / Clinical and molecular study in cuban patients with type I neurofibromatosis

Introducción: La neurofibromatosis tipo i es una enfermedad hereditaria, autosómica dominante, multisistémica, progresiva con penetrancia completa y expresividad variable. El análisis de las familias con marcadores moleculares permite realizar el diagnóstico por métodos indirectos. Objetivos: Estudiar dos familias cubanas con al menos un caso de neurofibromatosis tipo i e identificar los alelos resultantes del polimorfismo para el diagnóstico molecular. Métodos: Se realizó un estudio descriptivo a dos familias con al menos un caso de neurofibromatosis tipo i. Se extrajo el ADN con la técnica de precipitación salina y fue utilizada la reacción en cadena de la polimerasa para la amplificación del fragmento de interés. Se realizó la digestión enzimática con la enzima Rsai para analizar los alelos del polimorfismo estudiado y posteriormente hacer la electroforesis en gel de agarosa al 2 por ciento. Resultados: Las manifestaciones clínicas más frecuentes fueron las manchas color café con leche, pecas axilares e inguinales y lesiones óseas. Se detectaron los alelos 1 y 2 al analizar el polimorfismo en las muestras. Las frecuencias alélicas fueron 38,5 por ciento y 61,5 por ciento respectivamente. Conclusiones: Fueron identificadas las principales manifestaciones clínicas en los pacientes. La técnica para el análisis del polimorfimo permitió el estudio molecular en las familias con neurofibromatosis tipo i. Se detectaron los alelos del marcador molecular y sus frecuencias. Se realizó el diagnóstico molecular de los individuos sospechosos (AU)

Introduction: Neurofibromatosis type i is a hereditary, autosomal dominant, multisystemic, progressive disease with complete penetrance and variable manifestation. The analysis of families with molecular markers allows diagnosis by indirect methods. Objectives: To study two Cuban families with at least one case of neurofibromatosis type i and to identify the alleles resulting from the polymorphism for molecular diagnosis. Methods: A descriptive study of two families with at least one case of neurofibromatosis type i was performed. DNA was extracted with the saline precipitation technique and polymerase chain reaction was used for amplification of the fragment of interest. Enzymatic digestion was performed with the RsaI enzyme to analyze the alleles of the polymorphism studied and then to perform electrophoresis in 2 percent agarose gel. Results: The most frequent clinical manifestations were café-au-lait spots, axillary and inguinal freckles and bone lesions. Alleles 1 and 2 were detected when analyzing the polymorphism in the samples. The allele frequencies were 38.5 percent and 61.5 percent respectively. Conclusions: The main clinical manifestations in patients were identified. The technique for polymorphism analysis allowed the molecular study in the families with neurofibromatosis type i. The alleles of the molecular marker and their frequencies were detected. Molecular diagnosis of suspected individuals was performed (AU)

Abdominal tumors in patients with neurofibromatosis type I: Genotype-phenotype relationships.

BACKGROUND: Gastrointestinal stromal tumors have been detected in 25% of the necropsies performed on NF1 patients, but have been reported only in 7% of NF1 patients in the largest series. Such data imply an important gap between the true presence of tumors and those diagnosed. Few genotype-phenotype relationships have been described but to date none referring to abdominal tumors. OBJECTIVES: Evaluate retrospectively the efficacy of a regular and proactive follow-up of NF1 patients to early diagnose abdominal tumors and report their mutations. METHODS: Cohort study performed between 2010 and 2020, with 43 NF1 adult patients followed at our Dermatology department. RESULTS: Eight abdominal tumors were diagnosed in six patients, meaning that 14% of the followed patients developed an abdominal tumor. Five patients (83%) were asymptomatic. Five (83.3%) had a family history of NF1 with abdominal tumors (patients 1,2 and 3,4,5 were relatives). CONCLUSIONS: Although currently gastrointestinal routine screening investigations for asymptomatic patients are not recommended in the guidelines, the family aggregation in our series suggests it should be considered a close follow-up of the relatives of a patient with an NF1-related abdominal tumor. Also, for the first time, two mutations [c.2041C > T (p.Arg681Ter) and c.4537C > T (p.Arg1513*)] have been associated with family aggregation of abdominal tumors in NF1 patients.

Congenital difference of the hand and foot: Pediatric macrodactyly.

BACKGROUND: Macrodactyly is a very rare congenital difference that affects hands and feet with significant developmental and psychological implications. Macrodactyly is attributed to a somatic mutation in PIK3CA, a component of the mTOR pathway-related overgrowth disorders. Other medical conditions have been associated with macrodactyly (e.g., neurofibromatosis and Proteus syndrome). A thorough investigation of the presence of these conditions should be undertaken by the multidisciplinary team. The aim of this study is to summarize the main clinical characteristics and associated conditions, with an emphasis on diagnosis and surgical treatment options. MATERIALS AND METHODS: We present several clinical cases after a retrospective chart review of macrodactyly cases and a comprehensive literature review. RESULTS: The indications for surgery include peripheral compressive neuropathies (e.g., carpal tunnel syndrome), grotesque enlargement interfering with function, psychosocial distress due to the deformity, and macrodystrophic lipomatosis with proximal upper limb involvement. The main surgical treatment options are categorized as follows: digit reduction (e.g., soft tissue debulking, skeletal shortening/ terminalization, Barsky procedure, and Tsuge technique), limitation of growth (digital nerve stripping and epiphysiodesis), and correction of deviation (wedge or angulation osteotomy, arthrodesis, Millesi procedure for thumb macrodactyly correction, toe-to-hand transfer, ray resection, and combination of bony reduction and soft tissue debulking). CONCLUSIONS: Macrodactyly correction requires surgical experience and an individualized approach. Treatment is primarily surgical; however, efforts are being made to delineate the root cause of macrodactyly and provide nonoperative management.

A case report of mesenteric involvement in neurofibromatosis type 1.

Mutations in the Neurofibromatosis Type 1 (NF-1) gene, which is located on chromosome 17q11.2, are the cause of NF-1, an autosomal dominant hereditary condition in which tumors of the nerve system develop. Neurological, skeletal, and cutaneous abnormalities are symptoms of the condition. Of all gastrointestinal tract lesions, mesentery lesions are the least common. There are many gastrointestinal problems that can accompany mesenteric neurofibromas, or they may not. We describe a case of a 5-year-old kid with mesenteric neurofibromatosis, which results in bowel obstruction and abdominal discomfort. On a CT scan, the mesenteric vasculature was completely encircled by homogenous soft tissue lesions without any vessel wall invasion. Diffuse mesentery lesions were discovered during surgery, although they could not be fully removed.

Concurrent inhibition of FAK/SRC and MEK overcomes MEK inhibitor resistance in Neurofibromatosis Type I related malignant peripheral nerve sheath tumors.

Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft-tissue sarcomas which lack effective drugs. Loss of the RAS GTPase-activating protein NF1 and subsequent overactivation of mitogen-activated protein kinase kinase (MAPK) signaling exist nearly uniformly in MPNST, making MAPK inhibition a promising therapeutic intervention. However, the efficacy of MEK inhibitor (MEKi) monotherapy was limited in MPNST and the relative mechanisms remained largely unexplored. In this study, we generated three MEKi-resistant cell models and investigated the mechanisms of MEKi resistance using high-throughput transcriptomic sequencing. We discovered that cell apoptosis and cell cycle arrest induced by MEKi were rescued in MEKi-resistant cells and the upregulation of LAMA4/ITGB1/FAK/SRC signaling conferred resistance to MEKi. In addition, concurrent inhibition of MAPK signaling and FAK/SRC cascade could sensitize MPNST cells to MEKi. Our findings provide potential solutions to overcome MEKi resistance and effective combination therapeutic strategies for treating MPNSTs.

The gene diagnosis of neurofibromatosis type I with headache as the main symptom: A case report and review of the literature.

Neurofibromatosis type I (NF1) is an autosomal dominant disease. Some NF1 patients experience atypical clinical manifestations, genetic testing is not widely available, and the types of mutations vary; thus, they are prone to misdiagnosis and missed diagnosis. Although headache is not included in the diagnostic criteria for NF1, the incidence of headache in NF1 patients is not low. We report an NF1 family in which the proband presented with prominent headache and atypical clinical presentation, with limited skin pigmentation. We identified a frameshift mutation (c.1541_1542del, p. Q514Rfs*) in the NF1 gene by whole-exome sequencing of this family, and the patients were diagnosed with NF1. We hope to attract the attention of clinicians to these patients and improve genetic testing as soon as possible to increase the diagnosis rate.