NF2-related schwannomatosis and other schwannomatosis: an updated genetic and epidemiological study.

OBJECTIVES: New diagnostic criteria for NF2-related schwannomatosis (NF2) were published in 2022. An updated UK prevalence was generated in accordance with these, with an emphasis on the rate of de novo NF2 (a 50% frequency is widely quoted in genetic counselling). The distribution of variant types among de novo and familial NF2 cases was also assessed. METHODS: The UK National NF2 database identifies patients meeting updated NF2 criteria from a highly ascertained population cared for by England's specialised service. Diagnostic prevalence was assessed on 1 February 2023. Molecular analysis of blood and, where possible, tumour specimens for NF2, LZTR1 and SMARCB1 was performed. RESULTS: 1084 living NF2 patients were identified on prevalence day (equivalent to 1 in 61 332). The proportion with NF2 inherited from an affected parent was only 23% in England. If people without a confirmed molecular diagnosis or bilateral vestibular schwannoma are excluded, the frequency of de novo NF2 remains high (72%). Of the identified de novo cases, almost half were mosaic. The most common variant type was nonsense variants, accounting for 173/697 (24.8%) of people with an established variant, but only 18/235 (7.7%) with an inherited NF2 pathogenic variant (p<0.0001). Missense variants had the highest proportion of familial association (56%). The prevalence of LZTR1-related schwannomatosis and SMARCB1-related schwannomatosis was 1 in 527 000 and 1 in 1.1M, respectively, 8.4-18.4 times lower than NF2. CONCLUSIONS: This work confirms a much higher rate of de novo NF2 than previously reported and highlights the benefits of maintaining patient databases for accurate counselling.

Radiation treatment of benign tumors in NF2-related-schwannomatosis: A national study of 266 irradiated patients showing a significant increase in malignancy/malignant progression.

Background: Radiation treatment of benign tumors in tumor predisposition syndromes is controversial, but short-term studies from treatment centers suggest safety despite apparent radiation-associated malignancy being reported. We determined whether radiation treatment in NF2-related schwannomatosis patients is associated with increased rates of subsequent malignancy (M)/malignant progression (MP). Methods: All UK patients with NF2 were eligible if they had a clinical/molecular diagnosis. Cases were NF2 patients treated with radiation for benign tumors. Controls were matched for treatment location with surgical/medical treatments based on age and year of treatment. Prospective data collection began in 1990 with addition of retrospective cases in 1969. Kaplan-Meier analysis was performed for malignancy incidence and survival. Outcomes were central nervous system (CNS) M/MP (2cm annualized diameter growth) and survival from index tumor treatment. Results: In total, 1345 NF2 patients, 266 (133-Male) underwent radiation treatments between 1969 and 2021 with median first radiotherapy age of 32.9 (IQR = 22.4-46.0). Nine subsequent CNS malignancies/MPs were identified in cases with only 4 in 1079 untreated (P < .001). Lifetime and 20-year CNS M/MP was ~6% in all irradiated patients-(4.9% for vestibular schwannomas [VS] radiotherapy) versus <1% in the non-irradiated population (P < .001/.01). Controls were well matched for age at NF2 diagnosis and treatment (Males = 133%-50%) and had no M/MP in the CNS post-index tumor treatment (P = .0016). Thirty-year survival from index tumor treatment was 45.62% (95% CI = 34.0-56.5) for cases and 66.4% (57.3-74.0) for controls (P = .02), but was nonsignificantly worse for VS radiotherapy. Conclusion: NF2 patients should not be offered radiotherapy as first-line treatment of benign tumors and should be given a frank discussion of the potential 5% excess absolute risk of M/MP.

ERN GENTURIS tumour surveillance guidelines for individuals with neurofibromatosis type 1.

Background: Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder, predisposing development of benign and malignant tumours. Given the oncogenic potential, long-term surveillance is important in patients with NF1. Proposals for NF1 care and its specific manifestations have been developed, but lack integration within routine care. This guideline aims to assimilate available information on NF1 associated tumours (based on evidence and/or expert opinion) to assist healthcare professionals in undertaking tumour surveillance of NF1 individuals. Methods: By comprehensive literature review, performed March 18th 2020, guidelines were developed by a NF1 expert group and patient representatives, conversant with clinical care of the wide NF1 disease spectrum. We used a modified Delphi procedure to overcome issues of variability in recommendations for specific (national) health care settings, and to deal with recommendations based on indirect (scarce) evidence. Findings: We defined proposals for personalised and targeted tumour management in NF1, ensuring appropriate care for those in need, whilst reducing unnecessary intervention. We also incorporated the tumour-related psychosocial and quality of life impact of NF1. Interpretation: The guideline reflects the current care for NF1 in Europe. They are not meant to be prescriptive and may be adjusted to local available resources at the treating centre, both within and outside EU countries. Funding: This guideline has been supported by the European Reference Network on Genetic Tumour Risk Syndromes (ERN GENTURIS). ERN GENTURIS is funded by the European Union. DGE is supported by the Manchester NIHRBiomedical Research Centre (IS-BRC-1215-20007).

Non-invasive brain stimulation modulates GABAergic activity in neurofibromatosis 1.

Neurofibromatosis 1 (NF1) is a single-gene disorder associated with cognitive phenotypes common to neurodevelopmental conditions such as autism. GABAergic dysregulation underlies working memory impairments seen in NF1. This mechanistic experimental study investigates whether application of anodal transcranial direct current stimulation (atDCS) can modulate GABA and working memory in NF1. Thirty-one NF1 adolescents 11-18 years, were recruited to this single-blind sham-controlled cross-over randomized trial. AtDCS or sham stimulation was applied to the left Dorsolateral Prefrontal Cortex (DLPFC) and MR Spectroscopy was collected before and after intervention in the left DLPFC and occipital cortex. Task-related functional MRI was collected before, during, and after stimulation. Higher baseline GABA+ in the left DLPFC was associated with faster response times on baseline working memory measures. AtDCS was seen to significantly reduced GABA+ and increase brain activation in the left DLPFC as compared to sham stimulation. Task performance was worse in the aTDCS group during stimulation but no group differences in behavioural outcomes were observed at the end of stimulation. Although our study suggests aTDCS modulates inhibitory activity in the DLPFC, further work is needed to determine whether repeated sessions of atDCS and strategies such as alternating current stimulation offer a better therapeutic approach.

Response assessment in paediatric intracranial ependymoma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group.

Response criteria for paediatric intracranial ependymoma vary historically and across different international cooperative groups. The Response Assessment in the Pediatric Neuro-Oncology (RAPNO) working group, consisting of an international panel of paediatric and adult neuro-oncologists, neuro-radiologists, radiation oncologists, and neurosurgeons, was established to address both the issues and the unique challenges in assessing the response in children with CNS tumours. We established a subcommittee to develop response assessment criteria for paediatric ependymoma. Current practice and literature were reviewed to identify major challenges in assessing the response of paediatric ependymoma to clinical trial therapy. For areas in which data were scarce or unavailable, consensus was reached through an iterative process. RAPNO response assessment recommendations include assessing disease response on the basis of changes in tumour volume, and using event-free survival as a study endpoint for patients entering clinical trials without bulky disease. Our recommendations for response assessment include the use of brain and spine MRI, cerebral spinal fluid cytology, neurological examination, and steroid use. Baseline postoperative imaging to assess for residual tumour should be obtained 24-48 h after surgery. Our consensus recommendations and response definitions should be prospectively validated in clinical trials.

Neuroanatomical correlates of working memory performance in Neurofibromatosis 1.

Introduction: Neurofibromatosis 1 (NF1) is a single-gene disorder associated with cognitive impairments, particularly with deficits in working memory. Prior research indicates that brain structure is affected in NF1, but it is unclear how these changes relate to aspects of cognition. Methods: 29 adolescents aged 11-17 years were compared to age and sex-matched controls. NF1 subjects were assessed using detailed multimodal measurements of working memory at baseline followed by a 3T MR scan. A voxel-based morphometry approach was used to estimate the total and regional gray matter(GM) volumetric differences between the NF1 and control groups. The working memory metrics were subjected to a principal component analysis (PCA) approach. Results: The NF1 groups showed increased gray matter volumes in the thalamus, corpus striatum, dorsal midbrain and cerebellum bilaterally in the NF1 group as compared to controls. Principal component analysis on the working memory metrics in the NF1 group yielded three independent factors reflecting high memory load, low memory load and auditory working memory. Correlation analyses revealed that increased volume of posterior cingulate cortex, a key component of the default mode network (DMN) was significantly associated with poorer performance on low working memory load tasks. Conclusion: These results are consistent with prior work showing larger subcortical brain volumes in the NF1 cohort. The strong association between posterior cingulate cortex volume and performance on low memory load conditions supports hypotheses of deficient DMN structural development, which in turn may contribute to the cognitive impairments in NF1.

ERN GENTURIS clinical practice guidelines for the diagnosis, treatment, management and surveillance of people with schwannomatosis.

A Guideline Group (GG) was convened from multiple specialties and patients to develop the first comprehensive schwannomatosis guideline. The GG undertook thorough literature review and wrote recommendations for treatment and surveillance. A modified Delphi process was used to gain approval for recommendations which were further altered for maximal consensus. Schwannomatosis is a tumour predisposition syndrome leading to development of multiple benign nerve-sheath non-intra-cutaneous schwannomas that infrequently affect the vestibulocochlear nerves. Two definitive genes (SMARCB1/LZTR1) have been identified on chromosome 22q centromeric to NF2 that cause schwannoma development by a 3-event, 4-hit mechanism leading to complete inactivation of each gene plus NF2. These genes together account for 70-85% of familial schwannomatosis and 30-40% of isolated cases in which there is considerable overlap with mosaic NF2. Craniospinal MRI is generally recommended from symptomatic diagnosis or from age 12-14 if molecularly confirmed in asymptomatic individuals whose relative has schwannomas. Whole-body MRI may also be deployed and can alternate with craniospinal MRI. Ultrasound scans are useful in limbs where typical pain is not associated with palpable lumps. Malignant-Peripheral-Nerve-Sheath-Tumour-MPNST should be suspected in anyone with rapidly growing tumours and/or functional loss especially with SMARCB1-related schwannomatosis. Pain (often intractable to medication) is the most frequent symptom. Surgical removal, the most effective treatment, must be balanced against potential loss of function of adjacent nerves. Assessment of patients' psychosocial needs should be assessed annually as well as review of pain/pain medication. Genetic diagnosis and counselling should be guided ideally by both blood and tumour molecular testing.

The role of artificial intelligence in paediatric neuroradiology.

Imaging plays a fundamental role in the managing childhood neurologic, neurosurgical and neuro-oncological disease. Employing multi-parametric MRI techniques, such as spectroscopy and diffusion- and perfusion-weighted imaging, to the radiophenotyping of neuroradiologic conditions is becoming increasingly prevalent, particularly with radiogenomic analyses correlating imaging characteristics with molecular biomarkers of disease. However, integration into routine clinical practice remains elusive. With modern multi-parametric MRI now providing additional data beyond anatomy, informing on histology, biology and physiology, such metric-rich information can present as information overload to the treating radiologist and, as such, information relevant to an individual case can become lost. Artificial intelligence techniques are capable of modelling the vast radiologic, biological and clinical datasets that accompany childhood neurologic disease, such that this information can become incorporated in upfront prognostic modelling systems, with artificial intelligence techniques providing a plausible approach to this solution. This review examines machine learning approaches than can be used to underpin such artificial intelligence applications, with exemplars for each machine learning approach from the world literature. Then, within the specific use case of paediatric neuro-oncology, we examine the potential future contribution for such artificial intelligence machine learning techniques to offer solutions for patient care in the form of decision support systems, potentially enabling personalised medicine within this domain of paediatric radiologic practice.

Enlarged Vestibular Aqueduct: Disease Characterization and Exploration of Potential Prognostic Factors for Cochlear Implantation.

OBJECTIVES: There is an unmet need to match the anticipated natural history of hearing loss (HL) in enlarged vestibular aqueduct (EVA) with clinical management strategies. The objectives of this study are therefore to provide a detailed case characterization of an EVA cohort and explore the relationship between candidate prognostic factors and timing of cochlear implant (CI) surgery. STUDY DESIGN: A multicenter retrospective review of patients diagnosed with EVA. SETTING: Patient data recruitment across three CI centers in the UK. PATIENTS: One hundred fifty patients with a radiological diagnosis of EVA from January 1995 to January 2021. MAIN OUTCOME MEASURES: Age at audiological candidacy for CI and age at first implant surgery. RESULTS: EVA was predominately a bilateral condition (144/ 150) with increased prevalence in women (M:F, 64:86). 51.7% of patients failed new-born hearing screening, with 65.7% having HL diagnosed by 1 year. Initial moderate to severe and severe to profound HL were reported most frequently. In 123 patients, median age that audiological candidacy for CI was met for at least one ear was 2.75 years. Median age at first CI was 5 years (140/150).Pendred syndrome (confirmed in 73 patients) and ethnicity, were not significantly associated with earlier CI surgery. Multivariate linear regression demonstrated that male patients have first CI surgery significantly earlier than females (coefficient -0.43, 95% CI [-0.82, -0.05), p-value = 0.028). CONCLUSIONS: This large UK EVA cohort provides evidence that patients should be closely monitored for CI candidacy within the first 3 years of life. Significantly, male gender is emerging as an independent prognostic factor for earlier assessment and first CI surgery.

A Neuroimaging Preparation Protocol Tailored for Autism.

This paper describes the key basic elements required for a successful multi-parametric MRI data acquisition in awake children with autism. The procedure was designed by taking into account methodological challenges arising from the acquisition of Resting State fMRI (RS fMRI) data, and factors such as cost, time, and staff availability. The ultimate aim was to prepare an imaging preparation protocol with high transferability to the whole autism spectrum, adaptable for use in a multi-site research with multiple time points. As part of a randomized pharmaco-intervention study, 31 children aged 4-10 years with Neurofibromatosis 1 and autism underwent MR imaging at baseline and end of intervention. The protocol consisted of tailored habituation instructions including gradual exposure to scanner noise, a social stories booklet, positive incentive strategies, and Play Therapy support. Success rate for initial acquisition was 71% for GABA+ MR spectroscopy at either location, 87% for perfusion, and 67% for diffusion assessment, and 71% for RS fMRI. Qualitative data indicated that 84% parents found the habituation protocol helpful. LAY SUMMARY: Here we describe a protocol for brain Magnetic Resonance Imaging (MRI) tailored for children with ASD to help reduce stress and avoid sedation during scanning. This procedure can make advanced medical imaging more accessible and promote a better MRI experience for families of children with ASD.

Disease course of neurofibromatosis type 2: a 30-year follow-up study of 353 patients seen at a single institution.

BACKGROUND: Limited data exist on the disease course of neurofibromatosis type 2 (NF2) to guide clinical trial design. METHODS: A prospective database of patients meeting NF2 diagnostic criteria, reviewed between 1990 and 2020, was evaluated. Follow-up to first vestibular schwannoma (VS) intervention and death was assessed by univariate analysis and stratified by age at onset, era referred, and inheritance type. Interventions for NF2-related tumors were assessed. Cox regression was performed to determine the relationship between individual factors from time of diagnosis to NF2-related death. RESULTS: Three hundred and fifty-three patients were evaluated. During 4643.1 follow-up years from diagnosis to censoring, 60 patients (17.0%) died. The annual mean number of patients undergoing VS surgery or radiotherapy declined, from 4.66 and 1.65, respectively, per 100 NF2 patients in 1990-1999 to 2.11 and 1.01 in 2010-2020, as the number receiving bevacizumab increased (2.51 per 100 NF2 patients in 2010-2020). Five patients stopped bevacizumab to remove growing meningioma or spinal schwannoma. 153/353 (43.3%) had at least one neurosurgical intervention/radiation treatment within 5 years of diagnosis. Patients asymptomatic at diagnosis had longer time to intervention and better survival compared to those presenting with symptoms. Those symptomatically presenting <16 and >40 years had poorer overall survival than those presenting at 26-39 years (P = .03 and P = .02, respectively) but those presenting between 16 and 39 had shorter time to VS intervention. Individuals with de novo constitutional variants had worse survival than those with de novo mosaic or inherited disease (P = .004). CONCLUSION: Understanding disease course improves prognostication, allowing for better-informed decisions about care.

The importance of genetic counseling and screening for people with pathogenic SMARCE1 variants: A family study.

Clear cell meningioma (CCM) is a rare variant of meningioma. In recent years, an association between cranial and spinal CCMs and germline loss of function mutations in the SMARCE1 gene (SWI/SNF chromatin remodeling complex subunit gene) has been discovered. We report a family with an incidental large spinal clear cell meningioma in a young adult following reflex screening for a germline loss of function pathogenic variant (PV) in the SMARCE1 gene. The index patient's mother and maternal grandfather were both also tested positive presymptomatically for SMARCE1. His mother developed intracranial and spinal meningiomas and his maternal grandfather developed a spinal CCM 4 years following a clear spinal MRI scan which required surgical excision. In this report we particularly emphasize the importance of genetic counseling and screening in siblings, parents and offspring of patients who are diagnosed with intracranial or spinal CCM in the context of SMARCE1 PVs. We recommend brain and spine Imaging screening of asymptomatic SMARCE1 PV carriers at least every 3 years, even if the baseline scan did not show any tumors.

A retrospective regional study of aqueduct stenosis and fourth ventricle outflow obstruction in the paediatric complex neurofibromatosis type 1 population; Aetiology, clinical presentation and management.

OBJECTIVES: Aqueduct stenosis (AS) and fourth ventricle outflow obstruction are rare associations of neurofibromatosis type 1 (NF1), resulting in ventriculomegaly and hydrocephalus requiring surgical treatment. This study aims to identify the prevalence of AS and its patterns of clinical presentation, aetiology and treatment in the paediatric complex NF1 population. PATIENTS AND METHODS: Patients with NF-1 aged 0-18 years were recruited from the Regional Genetic Family Register, following institutional review board approval. Magnetic resonance imaging data and clinical documents were reviewed with respect to clinical presentation, degree of ventriculomegaly, aetiological factors and management of AS and fourth ventricle outflow obstruction. RESULTS: 24 of the 233 paediatric patients seen within the NHS highly specialised service for complex NF1 were found to have AS or and fourth ventricle outflow obstruction. This included 13 males and 11 females with a mean age of 9 years 5 months (range 8 months - 17 years). The majority of patients with AS or fourth ventricle outflow obstruction presented with symptoms of raised intracranial pressure associated with ventriculomegaly and/or hydrocephalus (n = 18). However, in 25 % of patients, AS was an incidental finding on MRI and was observed both in the presence (n = 2) and absence (n = 4) of ventriculomegaly. In the majority of cases a single cause of AS was identified (n = 16), of which tectal plate thickening (n = 7) was most frequently observed. The remaining 8 patients had multiple causes of AS, in which tectal plate thickening (n = 7) and aqueductal webs (n = 5) were the most common observations. Surgery was performed on all patients with evidence of raised pressure (n = 8) by performing endoscopic third ventriculostomy (ETV) (n = 5) or ventriculoperitoneal (VP)-shunting (n = 3). Tectal plate thickening was most frequently observed in patients who underwent ETV (n = 3), followed by aqueductal web (n = 1) and T2-signal changes in the tectal plate (n = 1). Patients treated with VP-shunt had 4th ventricle outflow obstruction (n = 2) and a tectal plate tumour (n = 1). CONCLUSION: This study identifies that AS is more prevalent amongst the paediatric complex NF-1 population than previously reported, occurring in 10 % of cases. Our findings demonstrate that AS is most commonly symptomatic in presentation but can be asymptomatic in 25 % of paediatric complex NF1 patients. In this population, AS can occur both in the presence and absence of ventriculomegaly and therefore requires careful monitoring for development of hydrocephalus. In this study, over one third of patients (9 of 24 patients) with AS eventually required treatment.

Perceived fatigue in children and young adults with neurofibromatosis type 1.

AIM: This study describes the prevalence and severity of perceived fatigue in a young neurofibromatosis type 1 (NF1) population. METHODS: Ethical approval was obtained and NF1 affected Individuals aged 2-18 years from the Manchester's NF1 clinic invited along with any unaffected siblings. The PedsQL Multidimensional Fatigue Scale Parental and child report was used. This validated measure explores cognitive, physical and sleep/rest domains on a 0-100 scale. Higher scores indicate less fatigue. Fatigue scores in affected children were compared to unaffected siblings after adjusting for age, sex and Index of Multiple Deprivation and with published population standards using z-scores. RESULTS: A total of 286 families were invited and 75 affected and 16 siblings participated. There were significant differences between NF1 and controls in the aggregated fatigue core (child report 55 ± 19 vs. 75 (14), P < 0.001; parent 54 ± 20 vs. 73 ± 18, P = 0.001) and the three sub-domains: cognitive (child 48 ± 27 vs. 75 ± 23, P < 0.001), physical (child 59 ± 19 vs. 82 ± 14, P < 0.001) and sleep/rest (child 59 ± 19 vs. 71 ± 15, P = 0.018). Similar differences were seen when compared with published controls (aggregated child z-score -1.9 ± 1.4, P < 0.001; parent -3.2 ± 1.8, P < 0.001). Prevalence of severe fatigue indicated by scores <2 standard deviation below published means for healthy controls were also higher for children with NF on both parent and child reports. Agreement between child and parent reports were limited as is frequently seen in the literature. CONCLUSION: This study suggests that children with NF1 are affected by perceived fatigue when compared with healthy children who do not have NF1.

Incidence of mosaicism in 1055 de novo NF2 cases: much higher than previous estimates with high utility of next-generation sequencing.

PURPOSE: To evaluate the incidence of mosaicism in de novo neurofibromatosis 2 (NF2). METHODS: Patients fulfilling NF2 criteria, but with no known affected family member from a previous generation (n = 1055), were tested for NF2 variants in lymphocyte DNA and where available tumor DNA. The proportion of individuals with a proven or presumed mosaic NF2 variant was assessed and allele frequencies of identified variants evaluated using next-generation sequencing. RESULTS: The rate of proven/presumed mosaicism was 232/1055 (22.0%). However, nonmosaic heterozygous pathogenic variants were only identified in 387/1055 (36.7%). When variant detection rates in second generation nonmosaics were applied to de novo cases, we assessed the overall probable mosaicism rate to be 59.7%. This rate differed by age from 21.7% in those presenting with bilateral vestibular schwannoma <20 years to 80.7% in those aged ≥60 years. A mosaic variant was detected in all parents of affected children with a single-nucleotide pathogenic NF2 variant. CONCLUSION: This study has identified a very high probable mosaicism rate in de novo NF2, probably making NF2 the condition with the highest expressed rate of mosaicism in de novo dominant disease that is nonlethal in heterozygote form. Risks to offspring are small and probably correlate with variant allele frequency detected in blood.

Randomised controlled trial of simvastatin treatment for autism in young children with neurofibromatosis type 1 (SANTA).

Background: Neurofibromatosis 1 (NF1) is a monogenic model for syndromic autism. Statins rescue the social and cognitive phenotype in animal knockout models, but translational trials with subjects > 8 years using cognition/behaviour outcomes have shown mixed results. This trial breaks new ground by studying statin effects for the first time in younger children with NF1 and co-morbid autism and by using multiparametric imaging outcomes. Methods: A single-site triple-blind RCT of simvastatin vs. placebo was done. Assessment (baseline and 12-week endpoint) included peripheral MAPK assay, awake magnetic resonance imaging spectroscopy (MRS; GABA and glutamate+glutamine (Glx)), arterial spin labelling (ASL), apparent diffusion coefficient (ADC), resting state functional MRI, and autism behavioural outcomes (Aberrant Behaviour Checklist and Clinical Global Impression). Results: Thirty subjects had a mean age of 8.1 years (SD 1.8). Simvastatin was well tolerated. The amount of imaging data varied by test. Simvastatin treatment was associated with (i) increased frontal white matter MRS GABA (t(12) = - 2.12, p = .055), GABA/Glx ratio (t(12) = - 2.78, p = .016), and reduced grey nuclei Glx (ANCOVA p < 0.05, Mann-Whitney p < 0.01); (ii) increased ASL perfusion in ventral diencephalon (Mann-Whitney p < 0.01); and (iii) decreased ADC in cingulate gyrus (Mann-Whitney p < 0.01). Machine-learning classification of imaging outcomes achieved 79% (p < .05) accuracy differentiating groups at endpoint against chance level (64%, p = 0.25) at baseline. Three of 12 (25%) simvastatin cases compared to none in placebo met 'clinical responder' criteria for behavioural outcome. Conclusions: We show feasibility of peripheral MAPK assay and autism symptom measurement, but the study was not powered to test effectiveness. Multiparametric imaging suggests possible simvastatin effects in brain areas previously associated with NF1 pathophysiology and the social brain network. Trial registration: EU Clinical Trial Register (EudraCT) 2012-005742-38 (www.clinicaltrialsregister.eu).

Fanconi anemia with sun-sensitivity caused by a Xeroderma pigmentosum-associated missense mutation in XPF.

BACKGROUND: Fanconi anemia (FA) is an inherited genomic instability disorder with congenital and developmental abnormalities, bone marrow failure and predisposition to cancer early in life, and cellular sensitivity to DNA interstrand crosslinks. CASE PRESENTATION: A fifty-one-year old female patient, initially diagnosed with FA in childhood on the basis of classic features and increased chromosomal breakage, and remarkable sun-sensitivity is described. She only ever had mild haematological abnormalities and no history of malignancy. To identify and characterise the genetic defect in this lady, who is one of the oldest reported FA patients, we used whole-exome sequencing for identification of causative mutations, and functionally characterized the cellular phenotype. Detection of the novel splice site mutation c.793-2A > G and the previously described missense mutation c.1765C > T (p.Arg589Trp) in XPF/ERCC4/FANCQ assign her as the third individual of complementation group FA-Q. Ectopic expression of wildtype, but not mutant, XPF/ERCC4/FANCQ, in patient-derived fibroblasts rescued cellular resistance to DNA interstrand-crosslinking agents. Patient derived FA-Q cells showed impaired nuclear excision repair capacity. However, mutated XPF/ERCC4/FANCQ protein in our patient's cells, as in the two other patients with FA-Q, was detectable on chromatin, in contrast to XP-F cells, where missense-mutant protein failed to properly translocate to the nucleus. CONCLUSIONS: Patients with FA characteristics and UV sensitivity should be tested for mutations in XPF/ERCC4/FANCQ. The missense mutation p.Arg589Trp was previously detected in patients diagnosed with Xeroderma pigmentosum or Cockayne syndrome. Hence, phenotypic manifestations associated with this XPF/ERCC4/ FANCQ mutation are highly variable.

High-Grade Glioma is not a Feature of Neurofibromatosis Type 2 in the Unirradiated Patient.

BACKGROUND: The Manchester criteria for neurofibromatosis type 2 (NF2) include a range of tumors, and gliomas were incorporated in the original description. The gliomas are now widely accepted to be predominantly spinal cord ependymomas. OBJECTIVE: To determine whether these gliomas include any cases of malignant glioma (WHO grade III and IV) through a database review. METHODS: The prospective database consists of 1253 patients with NF2. 1009 are known to be alive at last follow-up. RESULTS: There was a single case of glioblastoma multiforme (GBM; World Health Organization grade IV) in the series and no WHO grade III gliomas. The GBM was in a patient who had previously undergone stereotactic radiosurgery for a vestibular schwannoma. CONCLUSION: High-grade gliomas are not a feature of NF2 in the unirradiated patient and should be excluded from the diagnostic criteria.

Malignant Peripheral Nerve Sheath Tumors are not a Feature of Neurofibromatosis Type 2 in the Unirradiated Patient.

BACKGROUND: The published literature suggests that malignant peripheral nerve sheath tumors (MPNST) occur at increased frequency in neurofibromatosis type 2 (NF2). A recent review based on incidence data in North America showed that 1 per 1000 cerebellopontine angle nerve sheath tumors were malignant. OBJECTIVE: To determine whether MPNST occurred spontaneously in NF2 by reviewing our NF2 database. METHODS: The prospective database consists of 1253 patients with NF2. One thousand and nine are known to be alive at last follow-up. The presence and laterality/pathology of vestibular schwannoma at diagnosis and last follow-up was sought. RESULTS: There were no cases of spontaneous MPNST with 2114 proven (n = 1150) and presumed benign (n = 964) vestibular schwannomas found. Two patients had developed MPNST (1 presumed) after having previously undergone stereotactic radiosurgery for a vestibular schwannoma. CONCLUSION: In this series, and from the literature, malignant transformation of a vestibular schwannoma was not a feature of NF2 in the unirradiated patient. NF2 patients should not be told that they have an increased risk of malignant change in a vestibular schwannoma unless they undergo radiation treatment. However, very much larger datasets are required before it can be determined whether there is any association between NF2 and MPNST in the unirradiated patient.

Ventricular metastatic dissemination of a paediatric craniopharyngioma: case report and literature review.

Distant intraventricular metastasis is extremely rare in childhood craniopharyngioma. Here, we report the isolated posterior ventricular recurrence of an adamantinomatous craniopharyngioma, in a child previously treated with surgery and proton beam therapy for local progression. The importance of surveillance imaging is highlighted, while specific surgical approaches and techniques are considered.