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Intellectual disability (ID) is a clinical sign reflecting diverse neurodevelopmental disorders that are genetically and phenotypically heterogeneous. Just recently, partial or complete deletion of methyl-CpG-binding domain 5 (MBD5) gene has been implicated as causative in the phenotype associated with 2q23.1 microdeletion syndrome. In the course of systematic whole-genome screening of individuals with unexplained ID by array-based comparative genomic hybridization, we identified de novo intragenic deletions of MBD5 in three patients leading, as previously documented, to haploinsufficiency of MBD5. In addition, we described a patient with an unreported de novo MBD5 intragenic duplication. Reverse transcriptase-PCR and sequencing analyses showed the presence of numerous aberrant transcripts leading to premature termination codon. To further elucidate the involvement of MBD5 in ID, we sequenced ten coding, five non-coding exons and an evolutionary conserved region in intron 2, in a selected cohort of 78 subjects with a phenotype reminiscent of 2q23.1 microdeletion syndrome. Besides variants most often inherited from an healthy parent, we identified for the first time a de novo nonsense mutation associated with a much more damaging phenotype. Taken together, these results extend the mutation spectrum in MBD5 gene and contribute to refine the associated phenotype of neurodevelopmental disorder. Keywords: MBD5; nonsense mutation; intragenic duplication; intellectual disability INTRODUCTION Methyl-CpG-binding domain 5 (MBD5) protein (OMIM *611472) is a member of the MBD protein family in which MECP2 (OMIM *300005) is involved in Rett syndrome, a prototypical neurodevelopmental disorder. MBD5 contains five non-coding exons at its 5 0 -end, followed by 10 coding exons. Two isoforms have been described, 1 the longer one contains 1494 amino acids and is encoded by exons 6-15, the second one contains 851 amino acids and is encoded by exons 6-9. Functional studies suggested that MBD5 is likely to contribute to the formation or function of heterochromatin. 1 Isoform 1 of MBD5 is highly expressed in brain and testis and isoform 2 is highly expressed in oocytes, which suggest a possible role in cerebral functions and in epigenetic reprogramming after fertilization. Recently, deletions encompassing MBD5, as well as intragenic MBD5 deletions have been identified in individuals with a phenotype of intellectual disability (ID), seizures, significant speech impairment, and behavioral problems. [2][3][4][5][6][7][8] In this study, we used pangenomic arraycomparative genomic hybridization (array-CGH) and capillary sequencing of MBD5 gene to investigate DNAs from patients with unexplained ID. We further extend the mutational spectrum of MBD5 with damaging intragenic duplication and nonsense mutation associated with a clinical spectrum of neurodevelopmental disorder.

HuR regulates cytoplasmic mRNA stability and translatability, and the HuR expression level has been shown to correlate with poor disease outcome in several cancer types; however, the prognostic value and potential pro-oncogenic properties of HuR in meningioma remain unclear. Thus, in the present study, we analysed 85 meningioma tissue samples to establish the relationship between HuR expression, tumour cell proliferation, and/or patient survival. In addition, we examined the anti-proliferative effects of HuR knockdown in two meningioma cell lines (IOMM-Lee and Ben-Men-1) and conducted transcriptome-wide analyses (IOMM-Lee cells) to elucidate the molecular consequences of HuR knockdown. The results of the present study showed HuR cytoplasmic expression to correlate positively with tumour grade (p = 1.2 × 10 ) and negatively with progression-free and overall survival (p = 0.01) time in human meningioma tissues. In vitro, siHuR-induced HuR knockdown was shown to reduce the growth of both Ben-Men-1 (p = 2 × 10 ) and IOMM-Lee (p = 4 × 10 ) cells. Transcriptome analyses revealed HuR knockdown in IOMM-Lee cells to deregulate the HIF1A signalling pathway (p = 1.5 × 10 ) and to up-regulate the expression of genes essential for the assembly of the cytoplasmic mRNA processing body, global genome nucleotide-excision repair, poly(A)-specific ribonuclease activity, the positive regulation of apoptosis and of cell cycle arrest, and the negative regulation of RNA splicing [p(FDR) < 0.001]. Interestingly, HuR knockdown under hypoxic culture conditions further potentiated the effects of HuR knockdown on cell growth, apoptosis, and HIF1A expression. We thus conclude that cytoplasmic HuR expression is a marker of poor prognosis in meningioma and that HuR is a promising potential therapeutic target for use in tumours refractory to standard therapies. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The 2007 World Health Organization histologic grading of meningiomas is associated with recurrence and clinical outcome. However, distinction of grade I from grade II (atypical) meningiomas can be challenging. In the World Health Organization classification, there are 4 parameters on the basis of which grade II status can be determined: mitotic rate, cytoarchitectural features, brain invasion, and/or histologic subtype. Furthermore, this classification fails to detect grade I recurrent meningiomas, for which other prognostic criteria would be needed. The aim of this study was to evaluate the respective value of several markers involved in cell cycle as effective tools to predict recurrence. This retrospective study was based on a series of 59 meningiomas (grade I: 32 of 59, grade II: 27 of 59, all harboring ≥4 mitoses/1.6 mm), analyzed with the following immunohistochemical markers: MCM6, Ki-67, PHH3, cyclin D1, and p53. We found a significant correlation between histologic grade and mean labeling index for MCM6 (grade I: 21.8% vs. grade II: 65.8%; P<0.001), Ki-67 (3.2% vs. 16.9%; P<0.001), PHH3 (0.7‰ vs. 2.8‰; P<0.001), cyclin D1 (50.4% vs. 70.0%; P=0.005), and p53 (17.3% vs. 32.4%; P=0.017). Histologic grading and mitotic index were correlated with progression-free survival (P=0.010 and P=0.020, respectively). A nearly linear correlation was found between progression-free survival and staining for MCM6 (P<0.001), Ki-67 (P=0.003), and PHH3 (P=0.037) but not for cyclin D1 (P=0.400) and p53 (P=0.758). The interobserver agreement coefficients for MCM6, Ki-67, PHH3, cyclin D1, and p53 were, respectively, 0.97 (95% confidence interval, 0.95-0.98), 0.93 (0.89-0.96), 0.81 (0.70-0.88), 0.90 (0.83-0.94), and 0.84 (0.73-0.90). In conclusion, because of its strong level of expression and sharp difference in labeling index between indolent and recurrent tumors, MCM6 is the most efficient marker to identify tumors with a high risk of recurrence.