Publications by authors named "Arnold Munnich"

Biallelic pathogenic variants in CNTNAP2, a gene encoding the contactin-associated protein-like 2, have been reported in patients with various clinical presentations including intellectual disability (ID), autistic spectrum disorders (ASD), psychiatric disorders, and focal epilepsy rarely associated to focal cortical dysplasia. We report four children carrying novel biallelic CNTNAP2 pathogenic variants. They present global developmental delay, psychiatric disorders, and focal epilepsy.

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  • - POLG deficiency is the most common cause of nuclear-encoded mitochondrial disorders, leading to a range of overlapping symptoms from infancy to adulthood, as seen in a study of 40 children with biallelic pathogenic variants.
  • - The study identified three main clinical patterns (neurologic, hepatic, gastrointestinal), with 24 patients requiring urgent care mainly due to severe neurologic issues like seizures and epilepsy.
  • - Most children with hepatic symptoms had the earliest onset and shortest survival rates, while those with gastrointestinal issues had milder symptoms and lived longer; overall, the prognosis was poor, with many fatalities occurring by age 10.
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ARID1B-related disorders constitute a clinical continuum, from classic Coffin-Siris syndrome to intellectual disability (ID) with or without nonspecific dysmorphic features. Here, we describe an 11-year-old boy with an ARID1B mutation whose phenotype changed from severe developmental delay and ID to a complex neurodevelopmental disorder with multidimensional impairments, including normal intelligence despite heterogeneous IQ scores, severe motor coordination disorder, oral language disorder and attention-deficit/hyperactivity disorder. Phenotypic changes occurred after early intensive remediation and paralleled the normalization of myelination impairments, as evidenced by early brain imaging.

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Claudin-25 (CLDN-25), also known as Claudin containing domain 1, is an uncharacterized claudin family member. It has less conserved amino acid sequences when compared to other claudins. It also has a very broad tissue expression profile and there is currently a lack of functional information from murine knockout models.

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Since 2008, FOXG1 haploinsufficiency has been linked to a severe neurodevelopmental phenotype resembling Rett syndrome but with earlier onset. Most patients are unable to sit, walk, or speak. For years, FOXG1 sequencing was only prescribed in such severe cases, limiting insight into the full clinical spectrum associated with this gene.

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Recent studies using cell type-specific knockout mouse models have improved our understanding of the pathophysiological relevance of suppressor of lin-12-like-HMG-CoA reductase degradation 1 (SEL1L-HRD1) endoplasmic reticulum-associated (ER-associated) degradation (ERAD); however, its importance in humans remains unclear, as no disease variant has been identified. Here, we report the identification of 3 biallelic missense variants of SEL1L and HRD1 (or SYVN1) in 6 children from 3 independent families presenting with developmental delay, intellectual disability, microcephaly, facial dysmorphisms, hypotonia, and/or ataxia. These SEL1L (p.

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Atypical progeroid syndromes (APS) are premature aging syndromes caused by pathogenic LMNA missense variants, associated with unaltered expression levels of lamins A and C, without accumulation of wild-type or deleted prelamin A isoforms, as observed in Hutchinson-Gilford progeria syndrome (HGPS) or HGPS-like syndromes. A specific LMNA missense variant, (p.Thr528Met), was previously identified in a compound heterozygous state in patients affected by APS and severe familial partial lipodystrophy, whereas heterozygosity was recently identified in patients affected by Type 2 familial partial lipodystrophy.

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Bi-allelic variants in the mitochondrial arginyl-transfer RNA synthetase (RARS2) gene have been involved in early-onset encephalopathies classified as pontocerebellar hypoplasia (PCH) type 6 and in epileptic encephalopathy. A variant (NM_020320.3:c.

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Purpose: To assess the value of having an onsite genetic counseling service integrated into an assisted reproductive technology (ART) center.

Methods: Since January 2021, we have offered genetic counseling at our ART center for couples whose medical history suggests risk of transmission of a genetic disorder. The percentage of couples referred for genetic counseling, the distribution of couples according to reasons for consultation, the mode of transmission in cases of Mendelian disorders, and the frequency of mutations for those with identified genetic disorders were determined.

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  • SRSF1 is a protein that plays a crucial role in mRNA processing and is essential for proper brain development; its complete loss is fatal during embryonic stages in mice.
  • Researchers identified 17 individuals with neurodevelopmental disorders (NDD) who have specific genetic changes in the SRSF1 gene, which lead to developmental delays, intellectual disability, and other health issues.
  • Advanced analysis techniques demonstrated that most genetic variants linked to SRSF1 result in a loss of its function, causing syndromic NDD due to impaired splicing activity.
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Background And Purpose: Stroke-like episodes (SLEs) are defined as acute onset of neurological symptoms mimicking a stroke and radiological lesions non-congruent to vascular territory. We aimed to analyze the acute clinical and radiological features of SLEs to determine their pathophysiology.

Methods: We performed a monocenter retrospective analysis of 120 SLEs in 60 children over a 20-year period.

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  • The CLDN5 gene is crucial for producing claudin-5, a protein that creates tight junctions in blood-brain barrier cells to control ion and solute movement, helping maintain a stable brain environment.
  • Recent research shows that reduced CLDN-5 expression in the blood-brain barrier is linked to an increased risk of neurological disorders, such as epilepsy and dementia.
  • The review discusses how proteins and supporting cells regulate CLDN-5, highlights drugs aimed at enhancing its expression, explores a unique gain-of-function mutation associated with a childhood condition, and examines the impact of CLDN-5 on neurological disease development in animal models.
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  • The study investigates how mitochondrial deficiencies affect the early development of human embryos, specifically during preimplantation.
  • It finds that pathogenic mitochondrial variants lead to significant changes in gene expression, hindering development, cell differentiation, and overall survival.
  • Although the study's sample size was small due to the rarity of affected embryos, the results indicate a clear relationship between mitochondrial DNA variations and impaired embryonic development.
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  • - Transcription of mitochondrial DNA forms long polycistronic precursors, which are then processed into individual transcripts through cleavage by specific enzymes, mainly RNAseP and RNaseZ/ELAC2.
  • - The study describes five patients from three families with varying degrees of cardiomyopathy and neurological issues, highlighting genetic variants associated with these conditions.
  • - Enzymatic and immunoblot analyses revealed deficiencies in energy production pathways and a decrease in ELAC2 protein, supporting its role in processing mitochondrial tRNA precursors, indicating that cardiomyopathy may not always be a defining symptom of the disease.
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Background And Purpose: HIBCH and ECHS1 genes encode two enzymes implicated in the critical steps of valine catabolism, 3-hydroxyisobutyryl-coenzyme A (CoA) hydrolase (HIBCH) and short-chainenoyl-CoA hydratase (ECHS1), respectively. HIBCH deficiency (HIBCHD) and ECHS1 deficiency (ECHS1D) generate rare metabolic dysfunctions, often revealed by neurological symptoms. The aim of this study was to describe movement disorders spectrum in patients with pathogenic variants in ECHS1 and HIBC.

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Claudin-5 is the most enriched tight junction protein at the blood-brain barrier. Perturbations in its levels of expression have been observed across numerous neurological and neuropsychiatric conditions; however, pathogenic variants in the coding sequence of the gene have never been reported previously. Here, we report the identification of a novel de novo mutation (c.

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  • Pathogenic variants in the MYT1L gene lead to a neurodevelopmental disorder characterized by features like developmental delays, intellectual disabilities, and behavioral disorders.
  • A study analyzed genetic data from 40 previously unreported patients, adding to a total of 62 patients to better understand the clinical characteristics and genotype-phenotype correlations.
  • The research confirmed key phenotypic traits, introduced new clinical features, and emphasized that patients with certain genetic variants do not show distinct clinical differences, aiding in improved diagnosis and management of the disorder.
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Learning disabilities (LDs) are a major public health issue, affecting cognitive functions and academic performance for 8% of children. If LDs are not detected early and addressed through appropriate interventions, they have a heavy impact on these children in the social, educational, and professional spheres, at great cost to society. The BMT- (Batterie Modulable de Tests informatisée, or "computerized Adaptable Test Battery") enables fast, easy, reliable assessments for each cognitive domain.

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Most mitochondrial proteins are synthesized in the cytosol and targeted to mitochondria via N-terminal mitochondrial targeting signals (MTS) that are proteolytically removed upon import. Sometimes, MTS removal is followed by a cleavage of an octapeptide by the mitochondrial intermediate peptidase (MIP), encoded by the MIPEP gene. Previously, MIPEP variants were linked to four cases of multisystemic disorder presenting with cardiomyopathy, developmental delay, hypotonia and infantile lethality.

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  • Learning disabilities affect about 8% of children globally, leading to significant loss of opportunities and high costs for governments, highlighting the need for effective screening methods.
  • A new computerized assessment tool, the Adaptable Test Battery (BMT-), has been developed and validated for evaluating children's academic skills and cognitive functions, including areas like written language and math.
  • The study involved 1,074 Francophone children, showing strong psychometric properties of the BMT-, making it a reliable option for initial screening of learning disabilities in schools.
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De novo pathogenic variants in (chromosome alignment maintaining phosphoprotein 1), which encodes kinetochore-microtubule associated protein on 13q34, cause a rare neurodevelopmental disorder. We enrolled 14 individuals with pathogenic variants in that were documented by exome sequencing or gene panel sequencing. Medical history interviews, seizure surveys, Vineland Adapted Behavior Scales Second Edition, and other behavioral surveys were completed by primary caregivers of available participants in Simons Searchlight.

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OTC deficiency, an inherited urea cycle disorder, is caused by mutations in the X-linked OTC gene. Phenotype-genotype correlations are well understood in males but still poorly known in females. Taking advantage of a cohort of 130 families (289 females), we assessed the relative contribution of OTC enzyme activity, X chromosome inactivation, and OTC gene sequencing to genetic counseling in heterozygous females.

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