The Hao-Fountain syndrome protein USP7 regulates neuronal connectivity in the brain via a novel p53-independent ubiquitin signaling pathway.

Precise control of protein ubiquitination is essential for brain development, and hence, disruption of ubiquitin signaling networks can lead to neurological disorders. Mutations of the deubiquitinase USP7 cause the Hao-Fountain syndrome (HAFOUS), characterized by developmental delay, intellectual disability, autism, and aggressive behavior. Here, we report that conditional deletion of USP7 in excitatory neurons in the mouse forebrain triggers diverse phenotypes including sensorimotor deficits, learning and memory impairment, and aggressive behavior, resembling clinical features of HAFOUS. USP7 deletion induces neuronal apoptosis in a manner dependent of the tumor suppressor p53. However, most behavioral abnormalities in USP7 conditional mice persist despite p53 loss. Strikingly, USP7 deletion in the brain perturbs the synaptic proteome and dendritic spine morphogenesis independently of p53. Integrated proteomics analysis reveals that the neuronal USP7 interactome is enriched for proteins implicated in neurodevelopmental disorders and specifically identifies the RNA splicing factor Ppil4 as a novel neuronal substrate of USP7. Knockdown of Ppil4 in cortical neurons impairs dendritic spine morphogenesis, phenocopying the effect of USP7 loss on dendritic spines. These findings reveal a novel USP7-Ppil4 ubiquitin signaling link that regulates neuronal connectivity in the developing brain, with implications for our understanding of the pathogenesis of HAFOUS and other neurodevelopmental disorders.

Ectopic Fibrous Dysplasia Presenting As a Well-Circumscribed Orbital Mass.

The authors present the case of a middle-aged woman with subacute progressive swelling of the OD associated with pain and severely limited duction in all gazes. MRI demonstrated a ~3 cm circumscribed mass in the extraconal space, which displaced and distorted the globe and impinged upon ocular adnexa. She underwent lateral orbitotomy with bone osteotomy to remove the mass, and subsequent histopathologic examination showed woven bone set within a fibrotic background, microscopic features of fibrous dysplasia. Fibrous dysplasia is characterized by abnormal scar-like bony proliferation, typically within a preexisting structure of the skeletal system. To the authors' knowledge, this represents the first example of fibrous dysplasia presenting as an orbital mass unconnected to the craniofacial skeleton.

BRAF mutations may identify a clinically distinct subset of glioblastoma.

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Prior studies examining the mutational landscape of GBM revealed recurrent alterations in genes that regulate the same growth control pathways. To this regard, ~ 40% of GBM harbor EGFR alterations, whereas BRAF variants are rare. Existing data suggests that gain-of-function mutations in these genes are mutually exclusive. This study was designed to explore the clinical, pathological, and molecular differences between EGFR- and BRAF-mutated GBM. We reviewed retrospective clinical data from 89 GBM patients referred for molecular testing between November 2012 and December 2015. Differences in tumor mutational profile, location, histology, and survival outcomes were compared in patients with EGFR- versus BRAF-mutated tumors, and microarray data from The Cancer Genome Atlas was used to assess differential gene expression between the groups. Individuals with BRAF-mutant tumors were typically younger and survived longer relative to those with EGFR-mutant tumors, even in the absence of targeted treatments. BRAF-mutant tumors lacked distinct histomorphology but exhibited unique localization in the brain, typically arising adjacent to the lateral ventricles. Compared to EGFR- and IDH1-mutant tumors, BRAF-mutant tumors showed increased expression of genes related to a trophoblast-like phenotype, specifically HLA-G and pregnancy specific glycoproteins, that have been implicated in invasion and immune evasion. Taken together, these observations suggest a distinct clinical presentation, brain location, and gene expression profile for BRAF-mutant tumors. Pending further study, this may prove useful in the stratification and management of GBM.

Acute Posterior Multifocal Placoid Pigment Epitheliopathy Complicated by Fatal Cerebral Vasculitis.

A 21-year-old man experienced unilateral vision loss associated with multiple atrophic chorioretinal lesions. He was treated for a presumptive diagnosis of acute retinal necrosis, but his vision did not improve with antiviral therapy. Over the course of several weeks, his symptoms progressed to involve both eyes. The fellow eye showed characteristic yellow-white placoid lesions, prompting treatment with oral corticosteroids for acute posterior multifocal placoid pigment epitheliopathy (APMPPE). Despite high-dose therapy with prednisone 80 mg daily, the patient developed the acute onset of mental status changes within the next several days. Neuroimaging revealed multifocal large-vessel strokes associated with cerebral edema; these infarcts led to herniation and death. Postmortem histopathologic examination confirmed granulomatous inflammation in both ocular and cerebral vasculatures. Together with findings from multimodal imaging obtained throughout this patient's clinical course, our findings support the notion that granulomatous choroiditis is the mechanism of the ocular lesions seen in APMPPE. This granulomatous inflammation can also affect cerebral vessels, leading to strokes.

Focal traumatic rupture of a dermoid cyst in a pediatric patient: case report and literature review.

BACKGROUND: Dermoid cysts are rare congenital teratomas that can occasionally rupture and cause chemical meningitis, neurological deficit, or hydrocephalus. Rarely, dermoid cysts in the pediatric population can rupture spontaneously and even more rarely rupture due to trauma. To date, there are only five documented cases of traumatic rupture of a dermoid cyst. A 2-year-old male presented with 5 days of left eye ptosis and ophthalmoplegia after suffering a fall and was found to have a ruptured left anterior clinoid dermoid cyst that was surgically resected. The patient had significant improvement postoperatively. SIGNIFICANCE: To the authors' knowledge, this is the first reported case in the literature of a ruptured dermoid cyst after trauma in a pediatric patient and the first case of a traumatically ruptured dermoid cyst presenting with neurological deficit.

Epidermal Growth Factor Receptor Extracellular Domain Mutations in Glioblastoma Present Opportunities for Clinical Imaging and Therapeutic Development.

We explored the clinical and pathological impact of epidermal growth factor receptor (EGFR) extracellular domain missense mutations. Retrospective assessment of 260 de novo glioblastoma patients revealed a significant reduction in overall survival of patients having tumors with EGFR mutations at alanine 289 (EGFRA289D/T/V). Quantitative multi-parametric magnetic resonance imaging analyses indicated increased tumor invasion for EGFRA289D/T/V mutants, corroborated in mice bearing intracranial tumors expressing EGFRA289V and dependent on ERK-mediated expression of matrix metalloproteinase-1. EGFRA289V tumor growth was attenuated with an antibody against a cryptic epitope, based on in silico simulation. The findings of this study indicate a highly invasive phenotype associated with the EGFRA289V mutation in glioblastoma, postulating EGFRA289V as a molecular marker for responsiveness to therapy with EGFR-targeting antibodies.

Autoimmune Encephalitis With Multiple Autoantibodies: A Diagnostic and Therapeutic Challenge.

INTRODUCTION: Indications for autoantibody testing in patients with rapid-onset cognitive impairment have expanded in step with the growing number of disease-associated autoantibodies and clinical syndromes. Although increased access to autoantibody testing has broadened our understanding of the spectrum of autoimmune encephalitis (AE), it has also produced new challenges associated with deciphering the contributions of disease-associated autoantibodies in patients with atypical clinical features and/or multiple autoantibodies. These challenges are illustrated through presentation of a patient with AE associated with autoantibodies against intracellular and cell-surface neuronal antigens. The implications of detection of multiple autoantibodies are considered in the context of relevant literature, and used to frame a diagnostic and therapeutic approach. CASE REPORT: A previously well 67-year-old man presented with encephalopathy and psychosis, impaired visual fixation, and ataxia, emerging over 3 months. Hu, CRMP-5, and NMDAR autoantibodies were identified in the cerebrospinal fluid. No malignancy was discovered despite extensive investigations. An aggressive course of immunotherapy temporarily stabilized his course; however, the patient succumbed to his illness 10 months after symptom onset. Lack of sustained response to immunotherapy and neuropathologic findings suggested that AE associated with Hu antibodies was primarily responsible for this patient's progressive decline. CONCLUSIONS: Multiple autoantibodies may be detected in patients with AE. When antibodies targeting intracellular and cell-surface antigens are detected together, investigation and treatment of syndromes associated with intracellular antibodies should be prioritized, acknowledging the link between these antibodies and irreversible neuronal injury. In paraneoplastic cases, prognosis may be tied to early detection and treatment of the underlying malignancy.

Rapid Clinical and Radiographic Response With Combined Dabrafenib and Trametinib in Adults With BRAF-Mutated High-Grade Glioma.

BRAF V600E mutations have been successfully treated with targeted therapy in melanoma, non-small cell lung cancer, and thyroid cancer. Interestingly, these mutations have also been identified in a subset of pediatric and adult brain tumors, with several cases reportedly responding to targeted therapy. However, these reports have been limited to single-agent BRAF inhibitor therapy and recurrent disease. Herein, we report dramatic clinical and radiographic responses to combination dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor) in 2 adults with high-grade gliomas (HGGs), with 1 patient treated in the first-line setting. These observations, together with prior case reports, advocate for routine screening of BRAF point mutations in adult HGGs, and suggest that treatment with dual-targeted therapy, even in newly diagnosed cases, is safe and effective.

Sarcoidosis presenting as granulomatous myositis in a 16-year-old adolescent.

BACKGROUND: Sarcoidosis is a multi-system disease characterized by the presence of non-caseating epithelioid granulomas in affected tissues, including skeletal muscle. These organized collections of immune cells have important pathophysiologic action including cytokine production leading to inflammation as well as enzymatic conversion of cholecalciferol to calcitriol via 1-α hydroxylase. There are limited reports of isolated granulomatous myositis causing hypercalcemia in pediatric patients. Our patient uniquely presented with symptoms from hypercalcemia and renal insufficiency caused by an overwhelming burden of granulomatous myositis in her lower extremities, but was otherwise asymptomatic. CASE PRESENTATION: A 16 year old Caucasian female presented with protracted symptoms of fatigue, nausea and prominent weight loss with laboratory evidence of hypercalcemia and renal insufficiency. She lacked clinical and physical findings of arthritis, weakness, rash, uveitis, fever, lymphadenopathy or respiratory symptoms. After extensive negative investigations, re-examination yielded subtle soft tissue changes in her lower extremities, with striking MRI findings of extensive myositis without correlative weakness or serum enzyme elevation. Biopsy showed the presence of non-caseating epithelioid granulomas and calcium oxalate crystals. The patient responded well to prednisone and methotrexate but relapsed with weaning of steroids. She reachieved remission with addition of adalimumab. CONCLUSIONS: Sarcoidosis should be considered in patients presenting with symptomatic hypercalcemia with no apparent causes and negative routine workup. The absences of decreased muscle strength or elevated muscle enzymes do not preclude the diagnosis of granulomatous myositis.

Immunogenomics of Hypermutated Glioblastoma: A Patient with Germline POLE Deficiency Treated with Checkpoint Blockade Immunotherapy.

We present the case of a patient with a left frontal glioblastoma with primitive neuroectodermal tumor features and hypermutated genotype in the setting of a POLE germline alteration. During standard-of-care chemoradiation, the patient developed a cervical spine metastasis and was subsequently treated with pembrolizumab. Shortly thereafter, the patient developed an additional metastatic spinal lesion. Using whole-exome DNA sequencing and clonal analysis, we report changes in the subclonal architecture throughout treatment. Furthermore, a persistently high neoantigen load was observed within all tumors. Interestingly, following initiation of pembrolizumab, brisk lymphocyte infiltration was observed in the subsequently resected metastatic spinal lesion and an objective radiographic response was noted in a progressive intracranial lesion, suggestive of active central nervous system (CNS) immunosurveillance following checkpoint blockade therapy. SIGNIFICANCE: It is unclear whether hypermutated glioblastomas are susceptible to checkpoint blockade in adults. Herein, we provide proof of principle that glioblastomas with DNA-repair defects treated with checkpoint blockade may result in CNS immune activation, leading to clinically and immunologically significant responses. These patients may represent a genomically stratified group for whom immunotherapy could be considered. Cancer Discov; 6(11); 1230-6. ©2016 AACR.See related commentary by Snyder and Wolchok, p. 1210This article is highlighted in the In This Issue feature, p. 1197.

Role of the phosphoinositide phosphatase FIG4 gene in familial epilepsy with polymicrogyria.

OBJECTIVE: The aim of this study was to identify the causal gene in a consanguineous Moroccan family with temporo-occipital polymicrogyria, psychiatric manifestations, and epilepsy, previously mapped to the 6q16-q22 region. METHODS: We used exome sequencing and analyzed candidate variants in the 6q16-q22 locus, as well as a rescue assay in Fig4-null mouse fibroblasts and immunohistochemistry of Fig4-null mouse brains. RESULTS: A homozygous missense mutation (p.Asp783Val) in the phosphoinositide phosphatase gene FIG4 was identified. Pathogenicity of the variant was supported by impaired rescue of the enlarged vacuoles in transfected fibroblasts from Fig4-deficient mice. Histologic examination of Fig4-null mouse brain revealed neurodevelopmental impairment in the hippocampus, cortex, and cerebellum as well as impaired cerebellar gyration/foliation reminiscent of human cortical malformations. CONCLUSIONS: This study extends the spectrum of phenotypes associated with FIG4 mutations to include cortical malformation associated with seizures and psychiatric manifestations, in addition to the previously described Charcot-Marie-Tooth disease type 4J and Yunis-Varón syndrome.

Defective autophagy in neurons and astrocytes from mice deficient in PI(3,5)P2.

Mutations affecting the conversion of PI3P to the signaling lipid PI(3,5)P(2) result in spongiform degeneration of mouse brain and are associated with the human disorders Charcot-Marie-Tooth disease and amyotrophic lateral sclerosis (ALS). We now report accumulation of the proteins LC3-II, p62 and LAMP-2 in neurons and astrocytes of mice with mutations in two components of the PI(3,5)P(2) regulatory complex, Fig4 and Vac14. Cytoplasmic inclusion bodies containing p62 and ubiquinated proteins are present in regions of the mutant brain that undergo degeneration. Co-localization of p62 and LAMP-2 in affected cells indicates that formation or recycling of the autolysosome is impaired. These results establish a role for PI(3,5)P(2) in autophagy in the mammalian central nervous system (CNS) and demonstrate that mutations affecting PI(3,5)P(2) can contribute to inclusion body disease.

Correction of the disease phenotype in canine leukocyte adhesion deficiency using ex vivo hematopoietic stem cell gene therapy.

Canine leukocyte adhesion deficiency (CLAD) represents the canine counter-part of the human disease leukocyte adhesion deficiency (LAD). Defects in the leukocyte integrin CD18 adhesion molecule in both CLAD and LAD lead to recurrent, life-threatening bacterial infections. We evaluated ex vivo retroviral-mediated gene therapy in CLAD using 2 nonmyeloablative conditioning regimens--200 cGy total body irradiation (TBI) or 10 mg/kg busulfan--with or without posttransplantation immunosuppression. In 6 of 11 treated CLAD dogs, therapeutic levels of CD18(+) leukocytes were achieved. Conditioning with either TBI or busulfan allowed long-term engraftment, and immunosuppression was not required for efficacy. The percentage of CD18(+) leukocytes in the peripheral blood progressively increased over 6 to 8 months after infusion to levels ranging from 1.26% to 8.37% at 1-year follow-up in the 6 dogs. These levels resulted in reversal or moderation of the severe CLAD phenotype. Linear amplification-mediated polymerase chain reaction assays indicated polyclonality of insertion sites. These results describe ex vivo hematopoietic stem cell gene transfer in a disease-specific, large animal model using 2 clinically applicable conditioning regimens, and they provide support for the use of nonmyeloablative conditioning regimens in preclinical protocols of retroviral-mediated gene transfer for nonmalignant hematopoietic diseases such as LAD.

Acute myeloid leukemia is associated with retroviral gene transfer to hematopoietic progenitor cells in a rhesus macaque.

We report, for the first time, a replication-defective retroviral vector-associated neoplasia in a nonhuman primate. Five years after transplantation with CD34+ cells transduced with a retroviral vector expressing enhanced green fluorescent protein (eGFP) and a drug-resistant variant of the dihydrofolate reductase gene (L22Y), a rhesus macaque developed a fatal myeloid sarcoma, a type of acute myeloid leukemia. Tumor cells contained 2 clonal vector insertions. One insertion was found in BCL2-A1, an antiapoptotic gene. This event suggests that currently available retroviral vectors may have long-term side effects, particularly in hematopoietic stem and progenitor cells.

Hematopoietic stem cell gene therapy: dead or alive?

Despite some reports of toxicity in recent clinical trials, many scientists believe that the use of gene therapy in the treatment of congenital genetic defects and acquired disorders has too much potential to abandon. Hematopoietic stem cells (HSCs) have been primary targets for gene therapy owing to their capacity for differentiation and self-renewal, whereby multiple cell lineages can potentially be corrected for the lifetime of an individual. These efforts represent a long-term investment towards broadening physicians' treatment options for patients whose diseases, in particular certain immunodeficiencies, are fatal and where no other therapy is available. We review the recent progress and clinical triumphs as well as the reported toxicity related to insertional mutagenesis. We also discuss the current risk-to-benefit estimates and future strategies to reduce the risks and allow full realization of clinical potential. Scientists are continually revising protocols: going both from "bench to bedside" and, as strikingly demonstrated by HSC gene therapy, from "bedside to bench."

Recurrent retroviral vector integration at the Mds1/Evi1 locus in nonhuman primate hematopoietic cells.

Recent reports linking insertional activation of LMO2 following gene therapy for X-linked severe combined immunodeficiency (X-SCID) have led to a re-evaluation of risks following gene therapy with retroviral vectors. In our analysis of 702 integration sites in rhesus macaques that underwent transplantation up to 7 years earlier with autologous CD34+ cells transduced with amphotropic murine leukemia virus (MLV)-derived retroviral vectors containing marker genes, we detected insertion into one locus, the Mds1/Evi1 region, a total of 14 times in 9 animals. Mds1/Evi1 integrations were observed stably long term, primarily in myeloid cells. We hypothesize that this over-representation likely results from an impact on the self-renewal and engraftment potential of CD34+ progenitor cells via insertional mutagenesis at this specific locus. There is no evidence of ongoing in vivo clonal expansion of the Mds1/Evi1 populations, and all animals are hematologically normal without evidence for leukemia. Characterization of integration sites in this relevant preclinical model provides critical information for gene therapy risk assessment as well as identification of genes controlling hematopoiesis.

Distinct genomic integration of MLV and SIV vectors in primate hematopoietic stem and progenitor cells.

Murine leukemia virus (MLV)-derived vectors are widely used for hematopoietic stem cell (HSC) gene transfer, but lentiviral vectors such as the simian immunodeficiency virus (SIV) may allow higher efficiency transfer and better expression. Recent studies in cell lines have challenged the notion that retroviruses and retroviral vectors integrate randomly into their host genome. Medical applications using these vectors are aimed at HSCs, and thus large-scale comprehensive analysis of MLV and SIV integration in long-term repopulating HSCs is crucial to help develop improved integrating vectors. We studied integration sites in HSCs of rhesus monkeys that had been transplanted 6 mo to 6 y prior with MLV- or SIV-transduced CD34(+)cells. Unique MLV (491) and SIV (501) insertions were compared to a set of in silico-generated random integration sites. While MLV integrants were located predominantly around transcription start sites, SIV integrants strongly favored transcription units and gene-dense regions of the genome. These integration patterns suggest different mechanisms for integration as well as distinct safety implications for MLV versus SIV vectors.