Publications by authors named "Charlotte Brasch Andersen"

Developmental and epileptic encephalopathies (DEEs) are early-onset conditions that cause intractable seizures and developmental delays. Missense variants in Gamma-aminobutyric acid type A receptor (GABAAR) subunits commonly cause DEEs. Ahring et al.

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  • The translation elongation factor eEF1A2 is crucial for binding aminoacyl-tRNA to the ribosome, and since 2012, 21 harmful variants have been linked to severe neurodevelopmental disorders, including epilepsy and intellectual disabilities.
  • A recent study gathered 26 patients with EEF1A2 variants, revealing a milder clinical profile than previously reported, with higher walking and language skills and lower rates of intellectual disability and epilepsy.
  • The research identified 8 new EEF1A2 variants and suggests that severe and moderate phenotypes are linked to specific protein regions affecting GTP exchange, while milder variants may affect secondary functions, contributing to a broader understanding
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Background: We report a three-generation family with isolated Alport-like retinal abnormalities in the absence of lenticonus, hearing loss, kidney disease, and detectable molecular genetic defects in known Alport-related genes.

Methods: Clinical examination includes ocular biomicroscopy, fundus photography, optical coherence tomography, dipstick urinalysis, serum creatinine assessment, and molecular genetic analysis.

Results: The proband, her mother, and her maternal grandmother had normal best-corrected visual acuity and normal visual fields in both eyes.

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Genetic conditions are often familial, but not all relatives receive counseling from the same institution. It is therefore necessary to ensure consistency in variant interpretation, counseling practices, and clinical follow up across health care providers. Furthermore, as new possibilities for gene-specific treatments emerge and whole genome sequencing becomes more widely available, efficient data handling and knowledge sharing between clinical laboratory geneticists and medical specialists in clinical genetics are increasingly important.

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  • Whole genome sequencing (WGS) is being increasingly used to diagnose rare diseases, but traditional methods often have low diagnostic yields, typically 25-30%.
  • In a study involving 122 rare disease patients and their relatives, a comprehensive bioinformatics approach led to a diagnostic yield of 35%, with 39% solved when including novel gene candidates.
  • The study also identified several novel genes, expanded the phenotypic understanding of existing conditions, and resulted in critical changes to clinical diagnoses and treatments for some patients.
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Developmental and epileptic encephalopathies (DEEs) are rare severe neurodevelopmental disorders with a cumulative incidence of 1:6.000 live births. Many epileptic conditions arise from single nucleotide variants in CACNA1A (calcium voltage-gated channel subunit alpha1 A), encoding the CaV2.

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Heterozygous, pathogenic CUX1 variants are associated with global developmental delay or intellectual disability. This study delineates the clinical presentation in an extended cohort and investigates the molecular mechanism underlying the disorder in a Cux1 mouse model. Through international collaboration, we assembled the phenotypic and molecular information for 34 individuals (23 unpublished individuals).

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Objective: This study aimed to assess the diagnostic yield of prenatal genetic testing using trio whole exome sequencing (WES) and trio whole genome sequencing (WGS) in pregnancies with fetal anomalies by comparing the results with conventional chromosomal microarray (CMA) analysis.

Methods: A total of 40 pregnancies with fetal anomalies or increased nuchal translucency (NT ≥ 5 mm) were included between the 12th and 21st week of gestation. Trio WES/WGS and CMA were performed in all cases.

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  • De novo variants contribute significantly to neurodevelopmental disorders (NDDs), but due to their rarity, understanding the full range of symptoms and genetic variations linked to specific genes like KDM6B poses a challenge.
  • The study of 85 individuals with KDM6B variants reveals that cognitive deficits are common, while features like coarse facies and skeletal issues are rare, indicating that existing descriptions may be misleading.
  • Through innovative testing methods and studies on Drosophila, the researchers highlight the critical role of KDM6B in cognitive function and the importance of international collaboration for accurate diagnosis of rare disorders.
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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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Purpose: SRRM2 encodes the SRm300 protein, a splicing factor of the SR-related protein family characterized by its serine- and arginine-enriched domains. It promotes interactions between messenger RNA and the spliceosome catalytic machinery. This gene, predicted to be highly intolerant to loss of function (LoF) and very conserved through evolution, has not been previously reported in constitutive human disease.

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Loss-of-function variants in () cause Siderius X-linked intellectual disability (ID) syndrome, hereafter called PHF8-XLID. PHF8 is a histone demethylase that is important for epigenetic regulation of gene expression. PHF8-XLID is an under-characterized disorder with only five previous reports describing different predicted loss-of-function variants in eight individuals.

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-related disorders (also known as White-Sutton syndrome) encompass a wide range of neurocognitive abnormalities and other accompanying anomalies. Disease severity varies widely among patients and studies investigating genotype-phenotype association are scarce. Therefore, our aim was to collect data on previously unreported patients and perform a large-scale phenotype-genotype comparison from published data.

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Purpose: Adducins interconnect spectrin and actin filaments to form polygonal scaffolds beneath the cell membranes and form ring-like structures in neuronal axons. Adducins regulate mouse neural development, but their function in the human brain is unknown.

Methods: We used exome sequencing to uncover ADD1 variants associated with intellectual disability (ID) and brain malformations.

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Background: Surfactant Protein D (SP-D) is a pattern recognition molecule belonging to the family of collectins expressed in multiple human organ systems, including the lungs. Previous studies have shown that SP-D levels in bronchoalveolar lavage samples decrease and serum levels increase in patients suffering from asthma, possibly due to a combination of induced SP-D synthesis and decreased air-blood barrier integrity. The aims of this study were to investigate whether serum levels of SP-D and common variants in the SP-D gene were associated with asthma in adolescents and young adults.

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  • - The YTHDF3 gene is crucial for reading a specific mRNA modification that affects mRNA stability and is necessary for normal brain development in animals.
  • - Despite a link to intellectual disabilities, YTHDF3 has not been previously recognized as a cause of Mendelian diseases, although studies suggest it may be important.
  • - Researchers found four cases of individuals with deletions affecting YTHDF3 who exhibited developmental delays and intellectual disabilities, proposing that losing one copy of this gene may lead to these neurodevelopmental issues.
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Xia-Gibbs syndrome (XGS) is a neurodevelopmental disorder characterized by intellectual disability, developmental delay, seizures, hypotonia, obstructive sleep apnoea and mild facial dysmorphism. Heterozygosity for loss-of-function variants in AHDC1, encoding the AT-hook DNA binding motif containing protein 1, were discovered in 2014 as the likely genetic cause of Xia-Gibbs syndrome. We present five patients with Xia-Gibbs syndrome caused by previously unreported variants in AHDC1.

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ZMYND11 is the critical gene in chromosome 10p15.3 microdeletion syndrome, a syndromic cause of intellectual disability. The phenotype of ZMYND11 variants has recently been extended to autism and seizures.

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We describe a genetic syndrome due to PGM2L1 deficiency. PGM2 and PGM2L1 make hexose-bisphosphates, like glucose-1,6-bisphosphate, which are indispensable cofactors for sugar phosphomutases. These enzymes form the hexose-1-phosphates crucial for NDP-sugars synthesis and ensuing glycosylation reactions.

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Background: With the increasing number of genomic sequencing studies, hundreds of genes have been implicated in neurodevelopmental disorders (NDDs). The rate of gene discovery far outpaces our understanding of genotype-phenotype correlations, with clinical characterization remaining a bottleneck for understanding NDDs. Most disease-associated Mendelian genes are members of gene families, and we hypothesize that those with related molecular function share clinical presentations.

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Background: Sufficient fetal fraction (FF) is crucial for quality control of NIPT (Non-Invasive Prenatal Test) results. Different factors influencing bioinformatic estimation of FF should be considered when implementing NIPT. To what extent the total number of sequencing reads influences FF estimate has been unexplored.

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Introduction: In Denmark, non-invasive prenatal testing (NIPT) has been used since 2013. We aimed to evaluate the early clinical use of NIPT in Danish public and private healthcare settings before NIPT became an integrated part of the national guidelines on prenatal screening and diagnosis in 2017.

Material And Methods: NIPT data were collected between March 2013 and June 2017 from national public registries and private providers.

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