Project description:Legius syndrome presents as an autosomal dominant condition characterized by café-au-lait macules with or without freckling and sometimes a Noonan-like appearance and/or learning difficulties. It is caused by germline loss-of-function SPRED1 mutations and is a member of the RAS-MAPK pathway syndromes. Most mutations result in a truncated protein and only a few inactivating missense mutations have been reported. Since only a limited number of patients has been reported up until now, the full clinical and mutational spectrum is still unknown. We report mutation data and clinical details in fourteen new families with Legius syndrome. Six novel germline mutations are described. The Trp31Cys mutation is a new pathogenic SPRED1 missense mutation. Clinical details in the 14 families confirmed the absence of neurofibromas, and Lisch nodules, and the absence of a high prevalence of central nervous system tumors. We report white matter T2 hyperintensities on brain MRI scans in 2 patients and a potential association between postaxial polydactyly and Legius syndrome.
Project description:Optic pathway glioma (OPG) comprises 10% of pediatric brain tumors and 40% of all pediatric low-grade gliomas (pLGGs). While generally considered benign pathologically, many require interventions with chemotherapy, radiation, or targeted therapies. Management has historically foregone tissue diagnosis given the classical clinical/radiographic presentation of these tumors, inability to safely remove the lesions surgically, and efficacy and safety of available chemotherapy options. Furthermore, when considering such aspects as their delicate location, the role of surgery continues to be heavily debated. More recently, however, a greater understanding of the genetic drivers of OPGs has made operative tissue sampling a critical step in management planning, specifically for patients without Neurofibromatosis, Type I (NF1). Given the need for long-term, complex management of pediatric OPGs, it is crucial that a multidisciplinary approach is employed, and the rapidly expanding role of molecular characterization be incorporated into their management.
Project description:Optic Pathway Glioma (OPG) is a relatively common brain tumour in childhood; however, there is scarce understanding of neuropsychological sequelae in these survivors. In this study, 12 children with diagnosis of OPG before 6 years of age received a comprehensive standardised assessment of visual perception, general intelligence and academic achievement, using adjustments to visual materials of the tests, to examine the extent of concurrent impairment in these functional domains. Information about vision, clinical and socio-demographic factors were extracted from medical records to assess the associations of neuropsychological outcomes with clinical and socio-demographic factors. Children with OPG exhibited high within-patient variability and moderate group-level impairment compared to test norms. Visual perception was the most impaired domain, while scholastic progression was age-appropriate overall. For cognition, core verbal and visuo-spatial reasoning skills were intact, whereas deficits were found in working memory and processing speed. Visual function was associated with tasks that rely on visual input. Children with OPG are at moderate risk of neuropsychological impairment, especially for visual perception and cognitive proficiency. Future research should elucidate further the relative contribution of vision loss and neurofibromatosis type 1 co-diagnosis within a large sample.
Project description:Legius syndrome (LS) is an autosomal dominant disorder caused by germline loss-of-function mutations in the sprouty-related, EVH1 domain containing 1 (SPRED1) gene. The phenotype of LS is multiple café au lait macules (CALM) with other commonly reported manifestations, including intertriginous freckling, lipomas, macrocephaly, and learning disabilities including ADHD and developmental delays. Since the earliest signs of LS and neurofibromatosis type 1 (NF1) syndrome are pigmentary findings, the two are indistinguishable and individuals with LS may meet the National Institutes of Health diagnostic criteria for NF1 syndrome. However, individuals are not known to have an increased risk for developing tumors (compared with NF1 patients). It is therefore important to fully characterize the phenotype differences between NF1 and LS because the prognoses of these two disorders differ greatly. We have developed a mutation database that characterizes the known variants in the SPRED1 gene in an effort to facilitate this process for testing and interpreting results. This database is free to the public and will be updated quarterly.
Project description:Optic pathway gliomas (OPGs) encompass two distinct categories: benign pediatric gliomas, which are characterized by favorable prognosis, and malignant adult gliomas, which are aggressive cancers associated with a poor outcome. Our review aims to explore the established standards of care for both types of tumors, highlight the emerging therapeutic strategies for OPG treatment, and propose potential alternative therapies that, while originally studied in a broader glioma context, may hold promise for OPGs pending further investigation. These potential therapies encompass immunotherapy approaches, molecular-targeted therapy, modulation of the tumor microenvironment, nanotechnologies, magnetic hyperthermia therapy, cyberKnife, cannabinoids, and the ketogenic diet. Restoring visual function is a significant challenge in cases where optic nerve damage has occurred due to the tumor or its therapeutic interventions. Numerous approaches, particularly those involving stem cells, are currently being investigated as potential facilitators of visual recovery in these patients.
Project description:Optic pathway gliomas (OPGs) are insidious, debilitating low-grade tumors. They can affect the optic nerve, optic chiasm, and optic tracts and can be sporadic or associated with neurofibromatosis type 1 (NF1). The location of OPGs within the optic pathway typically precludes complete resection or optimal radiation dose. Treatment is unnecessary for sporadic and NF1-related OPGs that do not cause visual impairments. Chemotherapy is the mainstay of treatment for patients with progressive disease. However, outcomes following standard treatments have been mixed, and standardized outcome measurements are lacking. In recent years, newer molecularly targeted therapies such as anti-vascular endothelial growth factor (VEGF) monoclonal antibody, mitogen-activated protein kinase (MAPK) inhibitor, and mammalian target of rapamycin (mTOR) inhibitor, represent a promising treatment modality.
Project description:In this study, we characterize translocations that are frequent in Low Grade Endometrial Stromal Sarcoma (LG-ESS) and Ossifying FibroMyxoid Tumors (OFMT). We find that the fusion protein assembles a mega-complex harboring both NuA4/TIP60 and PRC2 subunits and enzymatic activities and leads to mislocalization of chromatin marks in the genome, linked to aberrant gene expression.
Project description:The purpose of this study was to investigate the progression of changes in retinal ganglion cells and optic nerve glia in neurofibromatosis-1 (NF1) genetically-engineered mice with optic glioma. Optic glioma tumors were generated in Nf1+/- mice lacking Nf1 expression in GFAP+ cells (astrocytes). Standard immunohistochemistry methods were employed to identify astrocytes (GFAP, S100beta), proliferating progenitor cells (sox2, nestin), microglia (Iba1), endothelial cells (CD31) and retinal ganglion cell (RGC) axons (Neurofilament 68k) in Nf1+/-, Nf1(GFAP)CKO (wild-type mice with Nf1 loss in glial cells), and Nf1+/-(GFAP)CKO (Nf1+/- mice with Nf1 loss in glial cells) mice. Ultrastructural changes in the optic chiasm and nerve were assessed by electron microscopy (EM). RGC were counted in whole retina preparations using high-resolution, mosaic confocal microscopy following their delineation by retrograde FluoroGold labeling. We found that only Nf1+/-(GFAP)CKO mice exhibited gross pre-chiasmatic optic nerve and chiasm enlargements containing aggregated GFAP+/nestin+ and S100beta+/sox2+ cells (neoplastic glia) as well as increased numbers of blood vessels and microglia. Optic gliomas in Nf1+/-(GFAP)CKO mice contained axon fiber irregularities and multilamellar bodies of degenerated myelin. EM and EM tomographic analyses showed increased glial disorganization, disoriented axonal projections, profiles of degenerating myelin and structural alterations at nodes of Ranvier. Lastly, we found reduced RGC numbers in Nf1+/-(GFAP)CKO mice, supporting a model in which the combination of optic nerve Nf1 heterozygosity and glial cell Nf1 loss results in disrupted axonal-glial relationships, subsequently culminating in the degeneration of optic nerve axons and loss of their parent RGC neurons.
Project description:The SPRED1 gene encodes a protein involved in the Ras/MAPK (mitogen-activated protein kinase) signaling pathway. Mutations in SPRED1 have been reported to cause Legius Syndrome, a rare developmental disorder that shares some clinical features with Neurofibromatosis-1. Direct sequencing was used to define SPRED1 mutations. We present two previously undescribed mutations: a frameshift mutation causing a stop codon, which was identified in an Italian family (p.Ile60Tyrfs*18) and a missense variation, which was identified in one sporadic Italian case (p.Pro422Arg). Our results led us to hypothesize that these modifications may contribute to the Legius Syndrome phenotype. Further studies will be needed to determine the roles of these mutations in the mechanisms of Legius Syndrome.