Publications by authors named "Alix E"

Psychomotor delay, epilepsy and dysmorphic features are clinical signs which are described in multiple syndromes due to chromosomal imbalances or mutations involving key genes implicated in the stages of Early Embryonic Development. In this context, we report a 10 years old Tunisian patient with these three signs. Our objective is to determine the cause of developmental, behavioral and facial abnormalities in this patient.

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Extracellular adenosine is produced from ATP by CD39 and CD73, and can modulate tumor development by acting on cancer cells or immune cells. Adenosine metabolism has been poorly studied in uveal melanoma. We studied the protein levels of CD39 and CD73 in a small, well described cohort of patients with uveal melanoma.

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The Salmonella enterica effector SteD depletes mature MHC class II (mMHCII) molecules from the surface of infected antigen-presenting cells through ubiquitination of the cytoplasmic tail of the mMHCII β chain. This requires the Nedd4 family HECT E3 ubiquitin ligase Wwp2 and a tumor-suppressing transmembrane protein adaptor Tmem127. Here, through a proteomic screen of dendritic cells, we found that SteD targets the plasma membrane protein CD97 for degradation by a similar mechanism.

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The purpose of this study was to analyze the impact of copy number variations (CNV) on sporadic pituitary neuroendocrine tumors (PitNETs) prognosis, to identify specific prognosis markers according to the known clinico-pathological classification. CGH array analysis was performed on 195 fresh-frozen PitNETs (56 gonadotroph, 11 immunonegative, 56 somatotroph, 39 lactotroph and 33 corticotroph), with 5 years post-surgery follow-up (124 recurrences), classified according to the five-tiered grading classification (invasion, Ki-67, mitotic index and p53 positivity). Effect of alterations on recurrence was studied using logistic regression models.

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Article Synopsis
  • Researchers performed exome sequencing on two unrelated families with progressive myoclonus epilepsy and discovered a rare variant affecting the SLC7A6OS gene in both families.
  • The analysis showed that this genetic change caused splice site issues, leading to abnormal protein expression linked to the condition.
  • Haplotype analysis indicated a common ancestor between the families, supporting the idea that loss-of-function variants in SLC7A6OS could be a new genetic cause of this type of epilepsy.
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PIGC (OMIM 601730) encodes the PIGC protein, which is part of an enzyme complex involved in the biosynthesis of the glycosylphosphatidylinositol protein anchor. The other proteins in the complex include PIGA, PIGH, PIGQ, PIGY, PIGP and DPM2. Homozygous and compound heterozygous mutations in PIGC have recently been described to cause severe global developmental delay, intellectual disability, and seizures in two unrelated families, without indication of another system involvement or dysmorphism.

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The Salmonella enterica effector SteD depletes mature MHC class II (mMHCII) molecules from the surface of infected antigen-presenting cells through ubiquitination of the cytoplasmic tail of the mMHCII β chain. Here, through a genome-wide mutant screen of human antigen-presenting cells, we show that the NEDD4 family HECT E3 ubiquitin ligase WWP2 and a tumor-suppressing transmembrane protein of unknown biochemical function, TMEM127, are required for SteD-dependent ubiquitination of mMHCII. Although evidently not involved in normal regulation of mMHCII, TMEM127 was essential for SteD to suppress both mMHCII antigen presentation in mouse dendritic cells and MHCII-dependent CD4 T cell activation.

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Article Synopsis
  • Developmental and epileptic encephalopathies are serious epilepsy syndromes that affect brain development, and modern genetic tools have identified genetic causes that may lead to new treatments.
  • A new syndrome linked to bi-allelic loss-of-function variants in the GAD1 gene was identified in 11 patients from consanguineous families, with seizures appearing within the first two months of life.
  • Patients exhibited symptoms like joint contractures, cleft palate, and in some cases, death before age four, indicating a unique syndrome related to the deficiency of the GABA-producing enzyme GAD67.
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  • The report details a case of a 19-year-old male with mosaic trisomy 13, characterized by various health issues including intellectual disability and heart defects.
  • Genetic analysis revealed that the patient has some cells with an extra chromosome from a nonreciprocal translocation inherited from his healthy mother.
  • This is only the second known instance of a patient with trisomy 13 mosaicism experiencing severe aortic root dilation, and the authors explore potential mechanisms behind the mosaic condition, particularly the instability of interstitial telomeres.
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Objective: Somatostatin receptor type 5 (SST5) is inconsistently expressed by corticotroph tumors, with higher expression found in corticotropinomas having ubiquitin-specific protease 8 (USP8) mutations. Aims were to study the correlation between characteristics of corticotropinomas and SST5 expression/USP8 mutation status and to describe the response to pasireotide in 5 patients.

Design: Retrospective cohort study.

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Kabuki syndrome (KS, KS1: OMIM 147920 and KS2: OMIM 300867) is caused by pathogenic variations in KMT2D or KDM6A. KS is characterized by multiple congenital anomalies and neurodevelopmental disorders. Growth restriction is frequently reported.

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Polymicrogyria is a heterogeneous malformation of cortical development microscopically defined by an excessive folding of the cortical mantle resulting in small gyri with a fused surface. Polymicrogyria is responsible for a wide range of neurological symptoms (e.g.

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Reliable interpretation of comparative genomic hybridization array (aCGH) results requires centralization and normalization of the data. We evaluated the reliability of aCGH centralization by comparing aCGH results (with classical centralization-normalization steps) to fluorescence in situ hybridization (FISH) results. In addition, we propose a method to correct centralization bias.

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We report on a prenatally diagnosed unusual case of inverted terminal duplication of the short arm of chromosome 2, leading to interstitial telomeric sequences (ITSs) and partial trisomy 2p. To our knowledge, there are only 4 further cases of pure partial trisomy 2p reported prenatally. Here, the mother was referred at 22 weeks of gestation for isolated fetal congenital heart malformation at ultrasound.

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Objectives: This study aims to describe how microarray comparative genomic hybridization (aCGH) has shifted to become a prenatal diagnosis tool at the Lyon university-hospital.

Materials And Methods: This retrospective study included all patients who were referred in the 3 pluridisciplinary centers for prenatal diagnosis of the Lyon university-hospital and who received a prenatal aCGH between June 2013 and June 2015. aCGH was systematically performed in parallel with a karyotype, using the PréCytoNEM array design.

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The SPI-2 type III secretion system (T3SS) of intracellular Salmonella enterica translocates effector proteins into mammalian cells. Infection of antigen-presenting cells results in SPI-2 T3SS-dependent ubiquitination and reduction of surface-localized mature MHC class II (mMHCII). We identify the effector SteD as required and sufficient for this process.

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Sensing bacterial products in the cytosol of mammalian cells by NOD-like receptors leads to the activation of caspase-1 inflammasomes, and the production of the pro-inflammatory cytokines interleukin (IL)-18 and IL-1β. In addition, mouse caspase-11 (represented in humans by its orthologs, caspase-4 and caspase-5) detects cytosolic bacterial LPS directly. Activation of caspase-1 and caspase-11 initiates pyroptotic host cell death that releases potentially harmful bacteria from the nutrient-rich host cell cytosol into the extracellular environment.

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Taybi-Linder syndrome (TALS, OMIM 210710) is a rare autosomal recessive disorder belonging to the group of microcephalic osteodysplastic primordial dwarfisms (MOPD). This syndrome is characterized by short stature, skeletal anomalies, severe microcephaly with brain malformations and facial dysmorphism, and is caused by mutations in RNU4ATAC. RNU4ATAC is transcribed into a non-coding small nuclear RNA which is a critical component of the minor spliceosome.

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Brain banks manage and store fully clinically and pathologically characterised brains. The diversity of techniques used in research projects increases. These biological resource centres are made to adapt brain tissue processing.

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Idiopathic scoliosis (IS) is a spine deformity that affects approximately 3% of the population. The underlying causes of IS are not well understood, although there is clear evidence that there is a genetic component to the disease. Genetic mapping studies suggest high genetic heterogeneity, but no IS disease-causing gene has yet been identified.

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A convenient strategy to interrogate the biology of regulatory proteins is to replace individual domains by an equivalent domain from a related protein of the same species or from an ortholog of another species. It is generally assumed that the overall properties of the native protein are retained in the chimera, and that functional differences reflect only the specific determinants contained in the swapped domains. Here we used this strategy to circumvent the difficulty in obtaining crystals of Rickettsia prowazekii RalF, a bacterial protein that functions as a guanine nucleotide exchange factor for eukaryotic Arf GTPases.

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Tethering proteins play a key role in vesicular transport, ensuring that cargo arrives at a specific destination. The bacterial effector protein SidC and its paralog SdcA have been described as tethering factors encoded by the intracellular pathogen Legionella pneumophila. Here, we demonstrate that SidC proteins are important for early events unique to maturation of vacuoles containing Legionella and discover monoubiquitination of Rab1 as a new SidC-dependent activity.

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The intracellular bacterial pathogen Legionella pneumophila (Lp) evades destruction in macrophages by camouflaging in a specialized organelle, the Legionella-containing vacuole (LCV), where it replicates. The LCV maturates by incorporating ER vesicles, which are diverted by effectors that Lp injects to take control of host cell membrane transport processes. One of these effectors, RalF, recruits the trafficking small GTPase Arf1 to the LCV.

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Kabuki syndrome (KS) is a rare syndrome associating malformations with intellectual deficiency and numerous visceral, orthopedic, endocrinological, immune and autoimmune complications. The early establishment of a diagnostic of KS leads to better care of the patients and therefore prevents complications such as perception deafness, severe complications of auto-immune diseases or obesity. However, the diagnosis of KS remains difficult because based on the appreciation of facial features combined with other highly variable features.

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Objective: To determine the frequency and types of renal malformations, and to evaluate renal function in a cohort of patients with Kabuki syndrome (KS).

Study Design: Renal ultrasound scans and plasma creatinine measurements were collected from a French cohort of 94 patients with genotyped KS. Renal function was evaluated based on the estimated glomerular filtration rate.

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