Publications by authors named "Pascal Chambon"

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  • - Cat Eye Syndrome (CES) is a rare genetic disorder linked to a marker chromosome from chromosome 22, leading to diverse symptoms including iris coloboma, anal atresia, and preauricular tags, but these are present in less than half of the cases.
  • - An international study of 43 CES patients found that only 16% displayed all three classic symptoms, while 9% showed none; additional issues such as cardiac anomalies (51%) and intellectual disabilities (47%) were also common.
  • - The study highlights the significance of supernumerary marker chromosomes (sSMC), found in 91% of cases, with many parents showing mild traits, emphasizing the need for genetic counseling regarding recurrence risks.
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  • Researchers have linked harmful changes in the VEGFC gene to Milroy-like primary lymphedema, a genetic disorder that causes swelling in the legs due to lymphatic issues.
  • The study reports the first prenatal case of this condition in a fetus, which showed swelling in both feet during an ultrasound.
  • Chromosomal analysis found a deletion in the VEGFC gene, which was inherited from the mother and grandmother, showcasing the value of microarray analysis for diagnosing such genetic conditions before birth.
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  • - The study focuses on 46,XX SRY-positive males, who have a testicular disorder due to a translocation of the SRY gene, highlighting possible connections between short stature and complex chromosomal rearrangements.
  • - Research involved data from 12 laboratories, revealing that 89.5% of patients had SRY present and various X chromosome breakpoints, impacting gene structures, particularly with the ARSE gene in some cases.
  • - Despite observing differences in chromosome structure, the height comparison between patients with and without ARSE deletion showed no significant statistical difference, indicating other factors may influence stature in these individuals.
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  • - Tau proteins are essential for neuron function and are linked to neurodegenerative diseases like Alzheimer's and Frontotemporal dementia, where they accumulate abnormally.
  • - A specific genetic duplication at 17q21.31 was found to affect multiple genes, including MAPT, which encodes Tau, leading to increased MAPT mRNA levels in blood samples from affected individuals.
  • - Researchers created a model using iPSC-induced neurons from patients with the duplication to investigate how it causes different tauopathies and the resulting neurodegenerative mechanisms linked to elevated Tau protein levels.
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The prevalence of congenital hydrocephalus has been estimated at 1.1 per 1000 infants when including cases diagnosed before 1 year of age after exclusion of neural tube defects. Classification criteria are based either on CSF dynamics, pathophysiological mechanisms or associated lesions.

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  • Balanced translocations can lead to unbalanced chromosomal rearrangements being passed down to children, which often result in inherited chromosomal abnormalities present from conception.
  • In a study, two siblings inherited mosaic chromosomal rearrangements from their father, who had a balanced translocation, leading to similar health issues like intellectual disability and physical deformities.
  • Advanced genetic testing revealed two different cell types in the siblings’ blood, suggesting a postzygotic rescue mechanism caused these abnormal patterns to reoccur in both siblings.
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Background: Reverse transcription-quantitative PCR on nasopharyngeal swabs is currently the reference COVID-19 diagnosis method but exhibits imperfect sensitivity.

Methods: We developed a multiplex reverse transcription-digital droplet PCR (RT-ddPCR) assay, targeting 6 SARS-CoV-2 genomic regions, and evaluated it on nasopharyngeal swabs and saliva samples collected from 130 COVID-19 positive or negative ambulatory individuals, who presented symptoms suggestive of mild or moderate SARS-CoV2 infection.

Results: For the nasopharyngeal swab samples, the results obtained using the 6-plex RT-ddPCR and RT-qPCR assays were all concordant.

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  • * The results showed a high positive predictive value (PPV) of 87.8% from gene panel data and 86.4% from whole-exome sequencing, with perfect sensitivity and specificity for a subset of gene comparisons.
  • * The findings suggest that adopting an NGS-only approach could be more cost-effective and provide stable diagnostic yields, with the CANOES workflow enabling detection of CNVs at a detailed exon level that may be missed by other methods.
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Objective: Primary familial brain calcification (PFBC) is a rare cerebral microvascular calcifying disorder with diverse neuropsychiatric expression. Five genes were reported as PFBC causative when carrying pathogenic variants. Haploinsufficiency of SLC20A2, which encodes an inorganic phosphate importer, is a major cause of autosomal-dominant PFBC.

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Epidermal growth factor receptor (EGFR) amplification and EGFR variant III (EGFRvIII, deletion of exons 2-7) are of clinical interest for glioblastoma. The aim was to develop a digital PCR (dPCR)-based method using locked nucleic acid (LNA)-based hydrolysis probes, allowing the simultaneous detection of the EGFR amplification and EGFRvIII variant. Sixty-two patients were included.

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  • Autism spectrum disorder (ASD) is a genetic neurodevelopmental disorder that is being rapidly studied, with next-generation sequencing as the main tool for identifying genetic variants linked to ASD.
  • A study on 253 ASD patients revealed 217 prioritized genes associated with ASD susceptibility, with a detection rate of approximately 19.7% for genetic variants.
  • Researchers advise against labeling these identified genes as "causative of ASD," suggesting that the term "genetic susceptibility factor contributing to ASD" is more accurate for communicating to families.
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  • - Juvenile polyposis syndrome (JPS) is a genetic condition that increases the risk of developing polyps in the gastrointestinal tract, which can turn cancerous, with about 50% of cases linked to mutations in the BMPR1A and SMAD4 genes.
  • - There is a specific case of a young adult with a 10q22.3q23.1 deletion, associated with intellectual disabilities and congenital heart defects, who developed severe juvenile polyposis while having this genetic anomaly.
  • - The study suggests that diagnosing the 10q22.3q23.1 deletion early using advanced genetic screening could explain the lack of documented juvenile polyps in similar cases, emphasizing the need for regular digestive monitoring in
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  • Rare copy number variations (CNVs) cause many genetic diseases, and a new CNV assay using digital PCR and locked nucleic acid probes has been developed for easier confirmation and analysis.
  • The assay utilizes Roche's Universal ProbeLibrary, automates primer and probe selection, and assesses performance on 93 CNVs with high accuracy and low variation.
  • This universal dPCR CNV assay is cost-efficient and simplifies genomic medicine by offering a robust method for analyzing and interpreting genomic variations.
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Purposes: Hydrops fetalis is a life-threatening fetal condition, and 85% of all cases are classified as nonimmune hydrops fetalis (NIHF). Up to 15% of NIHF cases may be due to inborn errors of metabolism (IEM), but a large proportion of cases linked to metabolic disorders remains undiagnosed. This lack of diagnosis may be related to the limitations of conventional biological procedures, which involve sequential investigations and require multiple samples and steps.

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Yin and yang 1 (YY1) is a well-known zinc-finger transcription factor with crucial roles in normal development and malignancy. YY1 acts both as a repressor and as an activator of gene expression. We have identified 23 individuals with de novo mutations or deletions of YY1 and phenotypic features that define a syndrome of cognitive impairment, behavioral alterations, intrauterine growth restriction, feeding problems, and various congenital malformations.

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Objective: The aim of this study was to evaluate the efficacy of intrasphincteric injections of autologous myoblasts (AMs) in fecal incontinence (FI) in a controlled study.

Summary Of Background Data: Adult stem cell therapy is expected to definitively cure FI by regenerating damaged sphincter. Preclinical data and results of open-label trials suggest that myoblast therapy may represent a noninvasive treatment option.

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  • The study focuses on the unexpected prenatal diagnosis of sex chromosome aneuploidies (47, XXX and 47, XYY) in a French cohort to assess termination rates before and after multidisciplinary centers were established in 1997.
  • It found that most cases were diagnosed fortuitously, and maternal age was typically higher for 47, XXX cases, which had a slightly higher termination rate (22.9%) compared to 47, XYY (14.6%).
  • After 1997, significant decreases in termination rates were observed for both conditions, suggesting a positive impact of the new prenatal diagnostic centers.
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Semaphorins are a large family of secreted and membrane-associated proteins necessary for wiring of the brain. Semaphorin 5A (SEMA5A) acts as a bifunctional guidance cue, exerting both attractive and inhibitory effects on developing axons. Previous studies have suggested that SEMA5A could be a susceptibility gene for autism spectrum disorders (ASDs).

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  • Genetic alterations can happen while culturing embryonic and induced pluripotent stem cells, raising safety concerns for their future use in therapy.
  • In a study of human myoblast preparations, half showed normal karyotypes while the other half displayed minor genomic changes, including occasional chromosome 2 trisomy.
  • Despite these genomic abnormalities, the myoblasts did not demonstrate a risk of transformation into cancerous cells or exhibit growth advantages in extended cultures or animal models.
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  • A 51-year-old woman was found to have a cervical spinal cord tumor suspected to be a metastasis, but it was diagnosed as an anaplastic meningioma with features resembling adenocarcinoma.
  • Histological analysis showed distinct tissue characteristics, indicating either a rare case of meningioma with adenocarcinoma-like features or a metastatic adenocarcinoma within a meningioma, but further scans ruled out primary cancers.
  • This case underscores the importance of accurate diagnosis, as treatment and prognosis differ significantly between malignant meningiomas and metastatic adenocarcinomas.
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  • * Further analysis involving exome sequencing identified a nonsense mutation in a different family, affecting four males and emphasizing the connection between BRWD3 mutations and intellectual disability.
  • * The clinical symptoms associated with BRWD3-related intellectual disability include mild to moderate cognitive impairments, speech delays, behavioral issues, macrocephaly, distinctive facial features, and various skeletal abnormalities.
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  • Researchers used a high-resolution method called array-comparative genomic hybridization to detect copy number variations in the human genome.
  • They confirmed these variations with a new semiquantitative multiplex PCR assay on the Bio-Rad Experion system, which uses unlabeled DNA fragments.
  • The assay showed excellent repeatability and reproducibility, making it a reliable method for confirming genomic rearrangements detected by the initial screening method.
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Germline RUNX1 mutations result in a rare autosomal dominant condition characterized by qualitative and quantitative platelet defects and predisposition to the development of myeloid malignancies (familial platelet disorder with propensity to acute myeloid leukaemia, FPD/AML). Only 13 pedigrees have previously been described so far. We report on two novel germline RUNX1 mutations: (1) an out-of-frame 8 bp heterozygous deletion (c.

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