Publications by authors named "Laila El Khattabi"

Article Synopsis
  • - Microtubule affinity-regulating kinase 2 (MARK2) is crucial for neurons to develop properly, and variants in MARK2 have been linked to autism spectrum disorder (ASD) and other neurodevelopmental issues, with most being loss-of-function mutations.
  • - A study analyzed 31 individuals with MARK2 variants showing ASD along with unique facial features, finding that the loss of MARK2 disrupts early neuron development and leads to abnormal growth patterns in neural cells.
  • - Research using iPSC models and MARK2-deficient mice highlighted the link between MARK2 loss and issues in neuronal function, connecting it to the reduction of the WNT/β-catenin signaling pathway, while suggesting lithium as a potential treatment
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  • - The study examines how secondary genetic variants can influence the clinical features of individuals with primary disease-causing variants, suggesting that these modifiers play a significant role in disease expression.
  • - Specifically focusing on the 16p12.1 deletion, researchers identified various rare and common variants that predisposed individuals to specific developmental issues, such as neurological defects and microcephaly.
  • - By analyzing data from different cohorts, the findings indicate that the effects of primary and secondary variants on phenotype vary depending on the specific primary variant involved, highlighting the need for personalized approaches in treatment.
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  • Fontaine progeroid syndrome (FPS) is a newly identified genetic disorder linked to mutations in the SLC25A24 gene, resulting in severe physical abnormalities such as craniosynostosis and growth restrictions.
  • The first documented prenatal cases during the second trimester show different phenotypic features, including encephalocele and nephromegaly, while lacking some typical signs of FPS seen after birth.
  • The study highlights the importance of genetic testing methods like exome/genome sequencing for diagnosing rare syndromes, suggesting that FPS may involve a novel inheritance pattern.
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  • The study investigates the effectiveness of cell-free DNA (cfDNA) testing for detecting fetal aneuploidies in women with triplet pregnancies, as current data is limited compared to singleton pregnancies.
  • The research involved a retrospective analysis of 255 women who underwent cfDNA testing between 2017 and 2020, focusing primarily on trisomy 21 (T21) and secondarily on trisomy 18 (T18) and trisomy 13 (T13).
  • Results indicated that cfDNA testing can serve as a primary screening tool for major fetal aneuploidies in triplet pregnancies, highlighting the importance of informed patient consent before proceeding with the test.
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  • - The study aimed to assess the effectiveness of early morphologic ultrasound in women with atypical first trimester serum markers when combined with Non-Invasive Prenatal Testing (NIPT).
  • - Conducted at a single center over four years, the research analyzed data from 163 women, finding that while early ultrasounds detected serious cases like severe IUGR, they generally did not improve management in most cases.
  • - The conclusions suggest that routine early ultrasounds may be unnecessary due to the reliability of NIPT, and that ultrasounds should be reserved for cases with serum marker levels below 0.25 MoM to better identify conditions like triploidy.
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FMR1 premutation female carriers are at risk of developing premature/primary ovarian insufficiency (POI) with an incomplete penetrance. In this study, we determined the CGG repeat size among 1095 women with diminished ovarian reserve (DOR) / POI and characterized the CGG/AGG substructure in 44 women carrying an abnormal FMR1 repeat expansion number, compared to a group of 25 pregnant women carrying an abnormal FMR1 CGG repeat size. Allelic complexity scores of the FMR1 gene were calculated and compared between the two groups.

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We examined more than 97,000 families from four neurodevelopmental disease cohorts and the UK Biobank to identify phenotypic and genetic patterns in parents contributing to neurodevelopmental disease risk in children. We identified within- and cross-disorder correlations between six phenotypes in parents and children, such as obsessive-compulsive disorder (R = 0.32-0.

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Purpose: Premature ovarian insufficiency (POI) affects approximately 1% of women before the age of 40. Genetic contribution is a significant component of POI. The NOBOX gene was considered one of the major genetic causes of POI.

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We examined more than 38,000 spouse pairs from four neurodevelopmental disease cohorts and the UK Biobank to identify phenotypic and genetic patterns in parents associated with neurodevelopmental disease risk in children. We identified correlations between six phenotypes in parents and children, including correlations of clinical diagnoses such as obsessive-compulsive disorder (R=0.31-0.

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Spermatozoa have a unique genome organization. Their chromatin is almost completely devoid of histones and is formed instead of protamines, which confer a high level of compaction and preserve paternal genome integrity until fertilization. Histone-to-protamine transition takes place in spermatids and is indispensable for the production of functional sperm.

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Neurofibromatosis type 1 (NF1) is an autosomal dominant disease with complete penetrance but highly variable expressivity. In most patients, Next Generation Sequencing (NGS) technologies allow the identification of a loss-of-function pathogenic variant in the NF1 gene, a negative regulator of the RAS-MAPK pathway. We describe the 5-year diagnosis wandering of a patient with a clear NF1 clinical diagnosis, but no molecular diagnosis using standard molecular technologies.

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Article Synopsis
  • Premature ovarian insufficiency (POI) is a condition that affects some women under 40, causing their ovaries to not work properly.
  • The cause of POI can be from different reasons, like genetics or medical treatments, but in many cases, it is unknown.
  • Women with POI may not have their periods and their hormone levels are off, but sometimes they can still get pregnant and may need hormone therapy until they're about 51 years old.
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  • Chromosomal aberrations, including structural variations, are significant contributors to genetic diseases, and current detection methods like karyotyping and CNV microarrays have limitations in resolution and ability to identify certain types of anomalies.
  • The study assessed optical genome mapping (OGM) on ultra-high-molecular-weight DNA from 85 samples to detect known chromosomal aberrations, achieving 100% concordance with standard tests for non-centromeric breakpoints.
  • The findings suggest OGM could revolutionize genetic testing by providing a high-resolution, cost-effective approach for detecting a wide range of chromosomal aberrations, paving the way for advancements in clinical cytogenetics.
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  • Klinefelter syndrome (KS) is a leading cause of infertility in genetic males, often resulting in azoospermia, and fertility preservation techniques like TESE are more successful when done early.
  • A systematic review of six studies involving young men (ages 13-24) showed that most participants agreed to sperm collection; however, azoospermia was present in all homogenous KS cases, with some success in mosaic KS.
  • It’s recommended that fertility preservation be proposed for young men with KS, but the ideal age for initiating sperm collection should be tailored to individual circumstances and maturity levels.
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The Mediator complex plays an essential and multi-faceted role in regulation of RNA polymerase II transcription in all eukaryotes. Structural analysis of yeast Mediator has provided an understanding of the conserved core of the complex and its interaction with RNA polymerase II but failed to reveal the structure of the Tail module that contains most subunits targeted by activators and repressors. Here we present a molecular model of mammalian (Mus musculus) Mediator, derived from a 4.

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Epigenetic regulation of gene expression is tightly controlled by the dynamic modification of histones by chemical groups, the diversity of which has largely expanded over the past decade with the discovery of lysine acylations, catalyzed from acyl-coenzymes A. We investigated the dynamics of lysine acetylation and crotonylation on histones H3 and H4 during mouse spermatogenesis. Lysine crotonylation appeared to be of significant abundance compared to acetylation, particularly on Lys27 of histone H3 (H3K27cr) that accumulates in sperm in a cleaved form of H3.

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Article Synopsis
  • Structural variants (SVs), like copy number variants (CNVs) and balanced chromosome rearrangements (ABCRs), are often difficult to detect using traditional short-read sequencing methods due to repetitive sequences, which makes long-read technologies like 10X Genomics' Chromium an interesting alternative.* -
  • In a study involving 13 patients, short-read sequencing successfully identified known SVs in 10 of them, while the linked-read technology also detected 10 SVs, including one additional variant missed by the short-read method.* -
  • Ultimately, the study concluded that the 10X Genomics linked-read strategy did not significantly enhance the detection or characterization of SVs compared to the short-read sequencing approach.*
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Article Synopsis
  • This study investigates the Mediator complex's role in eukaryotic transcription using advanced techniques like CRISPR-Cas9 and cryo-electron microscopy (cryo-EM).
  • Researchers identified essential subunits necessary for recruiting RNA Polymerase II (Pol II) across the genome and discovered that non-essential subunits mainly influence certain promoters associated with multiple enhancers.
  • The findings challenge existing models by suggesting that Mediator and Pol II are not required for connecting regulatory DNA, indicating that Mediator acts more as a gateway for regulatory signals than just a structural component.
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  • The text refers to a correction made to a previously published article with the DOI 10.1038/s41525-017-0035-2.
  • The correction likely addresses errors or omissions in the original publication.
  • This ensures that readers have access to accurate and updated information related to the research discussed in the article.
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In thyroid cancers, MET receptor overexpression has been associated with higher risk of metastatic progression. In this study, it was shown that the anaplastic thyroid cancer (ATC)-derived TTA1 cell line overexpressed MET. By using FISH and relative quantification by qPCR, it was demonstrated that this overexpression resulted from a amplification with more than 20 copies.

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Cohesin extrusion is thought to play a central role in establishing the architecture of mammalian genomes. However, extrusion has not been visualized in vivo, and thus, its functional impact and energetics are unknown. Using ultra-deep Hi-C, we show that loop domains form by a process that requires cohesin ATPases.

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Background: To limit risks of miscarriages associated with invasive procedures of current prenatal diagnosis practice, we aim to develop a personalized medicine-based protocol for non-invasive prenatal diagnosis (NIPD) of monogenic disorders relying on the detection of paternally inherited mutations in maternal blood using droplet digital PCR (ddPCR).

Methods: This study included four couples at risk of transmitting paternal neurofibromatosis type 1 (NF1) mutations and four couples at risk of transmitting compound heterozygous CFTR mutations. NIPD was performed between 8 and 15 weeks of gestation, in parallel to conventional invasive diagnosis.

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Article Synopsis
  • Phelan-McDermid syndrome (PMS) is a genetic condition linked to deletions on chromosome 22q13, leading to symptoms like intellectual disability, speech delays, and autism spectrum disorders, with severity varying across individuals.
  • The study involved analyzing 85 patients and found that 28% had abnormalities in the corpus callosum, a brain structure important for communication between hemispheres, and identified genomic regions that may contribute to specific symptoms like lack of speech.
  • Additionally, researchers found significant genetic variations that might influence the severity of PMS and noted that some family members with the deletion could remain unaffected, indicating potential compensatory mechanisms for managing the disorder.
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