Project description:We report an infantile case of midline ‘supratentorial ependymoma ZFTA fusion-positive’ involving both the infra- and the supra-tentorial compartments (i.e., cerebellar vermis, pons and midbrain). The radiological features, i.e., the upward displacement and compression of the supratentorial anatomical structures and the infiltrative margins of the tumour towards the cerebellar vermis, suggested an infratentorial origin of the lesion with secondary involvement of the supratentorial compartment. This case adds to the limited literature of non-hemispheric ‘supratentorial ependymoma ZFTA fusion-positive’ occurring in midline structures, both supratentorial (pineal region, thalamus) and infratentorial (cervico-medullary region and spinal cord), and in the cerebellum. These cases highlight the need to consider this entity in the differential diagnosis of paediatric non-hemispheric lesions and raise the question of whether the inclusion of the location within the WHO definition of this tumour type may be too restrictive
Project description:Mutation of the gene encoding the ATP-dependent chromatin remodeler CHD7 causes CHARGE syndrome. The mechanisms underlying the neurodevelopmental deficits associated with the syndrome, which include cerebellar hypoplasia, developmental delay, coordination problems and autistic features, are not known. CHD7 is expressed in neural stem and progenitor cells, but its role in neurogenesis during brain development remains unknown. Here we show that deletion of Chd7 from cerebellar granule cell precursors (GCps) in the mouse results in reduced GCp proliferation, cerebellar hypoplasia, developmental delay and motor deficits. Genome-wide expression profiling revealed downregulated Reln gene expression in Chd7-deficient GCps. Recessive RELN mutations is associated with severe cerebellar hypoplasia in humans. We provide molecular and genetic evidence that reduced Reln expression contributes substantially to the GCp proliferative defect and cerebellar hypoplasia in GCp-specific Chd7 mouse mutants. Finally, we show that CHD7 is necessary for the maintenance of an open, accessible chromatin state at the Reln locus. Taken together, this study shows that Reln gene expression is regulated by chromatin remodeling, identifies CHD7 as a previously unrecognized upstream regulator of Reln and provides the first evidence that a mammalian CHD protein controls brain development by modulating chromatin accessibility in neuronal progenitors in vivo.
Project description:The choroid plexus (ChP) is a secretory tissue that produces cerebrospinal fluid (CSF) secreted into the ventricular system. It is a monolayer of secretory, multiciliated epithelial cells derived from neuroepithelial progenitors and overlying a stroma of mesenchymal cells of mesodermal origin. Zfp423, encoding a Kruppel-type zinc finger transcription factor essential for cerebellar development and mutated in rare cases of cerebellar vermis hypoplasia / Joubert syndrome and other ciliopathies, is expressed in the hindbrain roof plate (RP), from which the IV ventricleChP arises, and, later, in mesenchymal cells giving rise to the stroma and leptomeninges.Zfp423mutants display a marked reduction of the hindbrain ChP (hChP), which 1) fails to express established markers of its secretory function and genes implicated in its development and maintenance (Lmx1a, Otx2); 2) shows a perturbed expression of signaling pathways previously unexplored in hChP patterning (Wnt3); 3) displays a lack of multiciliated epithelial cells and a profound dysregulation of master genes of multiciliogenesis (Gmnc). Our results propose Zfp423as a master gene and one of the earliest known determinants of hChP development.
2020-10-29 | GSE160300 | GEO
Project description:A novel nonsense mutation of GLI3 induced non-syndromic polydactyly
Project description:TRIP4 is one of the subunits of the transcriptional coregulator ASC-1, a ribonucleoprotein complex that participates in transcriptional coactivation and RNA processing events. Recessive variants in the TRIP4 gene have been associated with spinal muscular atrophy with bone fractures as well as a severe form of congenital muscular dystrophy. Here we present the diagnostic journey of a patient with cerebellar hypoplasia and spinal muscular atrophy (PCH1) and congenital bone fractures. Initial exome sequencing analysis revealed no candidate variants. Reanalysis of the exome data by inclusion in the Solve-RD project resulted in the identification of a homozygous stop-gain variant in the TRIP4 gene, previously reported as disease-causing. This highlights the importance of analysis reiteration and improved and updated bioinformatic pipelines. Proteomic profile of the patient’s fibroblasts showed altered RNA-processing and impaired exosome activity supporting the pathogenicity of the detected variant. In addition, we identified a novel genetic form of PCH1, further strengthening the link of this characteristic phenotype with altered RNA metabolism.
Project description:The PRDM13 (PR Domain containing 13) putative chromatin modifier and transcriptional regulator functions downstream of the transcription factor PTF1A, which controls GABAergic fate in the spinal cord and neurogenesis in the hypothalamus. Here, we report a novel, recessive syndrome associated with PRDM13 mutation. Patients exhibited intellectual disability, ataxia with cerebellar hypoplasia, scoliosis and delayed puberty with congenital hypogonadotropic hypogonadism (CHH). Expression studies revealed Prdm13/PRDM13 transcripts in the developing hypothalamus and cerebellum in mouse and human. An analysis of hypothalamus and cerebellum development in mice homozygous for a Prdm13 mutant allele revealed a significant reduction in the number of Kisspeptin (Kiss1) neurons in the hypothalamus and PAX2+ progenitors emerging from the cerebellar ventricular zone. The latter was accompanied by ectopic expression of the glutamatergic lineage marker TLX3. Prdm13-deficient mice displayed cerebellar hypoplasia, normal gonadal structure, but delayed pubertal onset. Together, these findings identify PRDM13 as a critical regulator of GABAergic cell fate in the cerebellum and of hypothalamic kisspeptin neuron development, providing a mechanistic explanation for the co-occurrence of CHH and cerebellar hypoplasia in this syndrome. To our knowledge, this is the first evidence linking disrupted PRDM13-mediated regulation of Kiss1 neurons to CHH in humans.
Project description:Recessive mutations in EXOSC3, encoding a subunit of the human RNA exosome complex, cause Pontocerebellar hypoplasia type 1b (PCH1B). We report a boy with severe muscular hypotonia, psychomotor retardation, progressive microcephaly, and cerebellar atrophy. Biochemical abnormalities comprised mitochondrial Complex I and PDHc deficiency. Whole exome sequencing uncovered a known EXOSC3-mutation p.(D132A) as the underlying cause. In patient fibroblasts, >50% of the EXOSC3 protein was trapped in the cytosol. mtDNA-copy numbers in muscle were reduced to 40%, but mutations in the mtDNA and nuclear mitochondrial genes were excluded. RNA-seq of patient muscle showed highly increased mRNA-copy numbers, especially for genes encoding structural subunits of OXPHOS-complexes I, III, and IV, possibly due to reduced degradation by a dysfunctional exosome complex. This is the first case of mitochondrial dysfunction associated with an EXOSC3 mutation, which expands the phenotypic spectrum of PCH1B. We discuss the links between exosome and mitochondrial dysfunction.
Project description:Bulk RNA samples were recruited from GCE of the cerebellar vermis. We obtained two WT and two Kdm3b+/- mice samples for RNA-sequencing analysis. After trimming low-quality bases, the sequence reads were aligned using the STAR algorithm. Then, we quantified gene expression using the StringTie, resulting 16,447 genes expressed in cerebellum tissues.