Publications by authors named "Amraoui A"

Article Synopsis
  • CRISPR-Cas9 gene editing offers potential treatments for retinal dystrophies by targeting specific genes in retinal cells.
  • Unlike viral delivery methods that can cause long-term effects, this study focuses on transient delivery of Cas9 protein and guide RNA as ribonucleoprotein complexes.
  • The research shows these complexes can enter retinal cells directly, but higher concentrations can be toxic, highlighting the need for enhanced delivery techniques for safe and effective therapies.
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Hearing loss is a major health concern affecting millions of people worldwide with currently limited treatment options. In clarin-2-deficient Clrn2 mice, used here as a model of progressive hearing loss, we report synaptic auditory abnormalities in addition to the previously demonstrated defects of hair bundle structure and mechanoelectrical transduction. We sought an in-depth evaluation of viral-mediated gene delivery as a therapy for these hearing-impaired mice.

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This study investigates the views of contemporary Muslim jurists about withdrawing treatment of the terminally ill. Its aim is threefold. Firstly, it analyses jurists' views concerning core themes within the process of withdrawing treatment.

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Article Synopsis
  • In Tunisia, in-centre haemodialysis is the primary form of dialysis, but there's a shortage of machines, leading to the exploration of Home Haemodialysis (HHD) as a viable alternative.
  • The study aimed to analyze the costs of different home dialysis options, using Activity-Based Costing to evaluate the expenses associated with each modality.
  • Results showed that Home Peritoneal Dialysis was the cheapest option at 25,344 TND annually, while Conventional HHD was also a potential solution, suggesting the Tunisian health ministry could consider implementing it to enhance patient care.
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The inner ear is responsible for both hearing and balance. These functions are dependent on the correct functioning of mechanosensitive hair cells, which convert sound- and motion-induced stimuli into electrical signals conveyed to the brain. During evolution of the inner ear, the major changes occurred in the hearing organ, whereas the structure of the vestibular organs remained constant in all vertebrates over the same period.

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Usher syndrome (USH) is the most common cause of deaf-blindness in humans, with a prevalence of about 1/10,000 (~ 400,000 people worldwide). Cochlear implants are currently used to reduce the burden of hearing loss in severe-to-profoundly deaf patients, but many promising treatments including gene, cell, and drug therapies to restore the native function of the inner ear and retinal sensory cells are under investigation. The traditional clinical classification of Usher syndrome defines three major subtypes-USH1, 2 and 3-according to hearing loss severity and onset, the presence or absence of vestibular dysfunction, and age at onset of retinitis pigmentosa.

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Blindness and deafness are the most frequent sensory disorders in humans. Whatever their cause - genetic, environmental, or due to toxic agents, or aging - the deterioration of these senses is often linked to irreversible damage to the light-sensing photoreceptor cells (blindness) and/or the mechanosensitive hair cells (deafness). Efforts are increasingly focused on preventing disease progression by correcting or replacing the blindness and deafness-causal pathogenic alleles.

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Usher syndrome (USH) encompasses a group of clinically and genetically heterogenous disorders defined by the triad of sensorineural hearing loss (SNHL), vestibular dysfunction, and vision loss. USH is the most common cause of deaf blindness. USH is divided clinically into three subtypes-USH1, USH2, and USH3-based on symptom severity, progression, and age of onset.

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Article Synopsis
  • Progressive non-syndromic sensorineural hearing loss (PNSHL) is a prevalent sensory impairment in older adults, impacting over a third of those aged 65 and above, and includes conditions like noise-induced hearing loss and genetic forms such as delayed-onset autosomal dominant hearing loss.
  • PNSHL is considered a strong candidate for genetic therapies due to extensive research and the opportunity to intervene before significant hearing loss occurs, with various gene therapy strategies available, including viral and non-viral methods as well as gene editing techniques.
  • To effectively develop and test these therapies, creating a reliable in vitro model of the human inner ear from induced pluripotent stem cells (iPSCs) is essential, which could lead to
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Deafness, the most frequent sensory deficit in humans, is extremely heterogeneous with hundreds of genes involved. Clinical and genetic analyses of an extended consanguineous family with pre-lingual, moderate-to-profound autosomal recessive sensorineural hearing loss, allowed us to identify CLRN2, encoding a tetraspan protein, as a new deafness gene. Homozygosity mapping followed by exome sequencing identified a 14.

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Hearing impairment is the most frequent sensory deficit in humans of all age groups, from children (1/500) to the elderly (more than 50% of the over-75 s). Over 50% of congenital deafness are hereditary in nature. The other major causes of deafness, which also may have genetic predisposition, are aging, acoustic trauma, ototoxic drugs such as aminoglycosides, and noise exposure.

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Usher syndrome (USH) is a major cause of deaf-blindness in humans, affecting ∼400 000 patients worldwide. Three clinical subtypes, USH1-3, have been defined, with 10 USH genes identified so far. In recent years, in addition to identification of new Usher genes and diagnostic tools, major progress has been made in understanding the role of Usher proteins and how they cooperate through interaction networks to ensure proper development, architecture and function of the stereociliary bundle at the apex of sensory hair cells in the inner ear.

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Molecular diagnosis of rare inherited palmoplantar keratoderma (PPK) is still challenging. We investigated at the clinical and genetic level a consanguineous Tunisian family presenting an autosomal dominant atypical form of transgrediens and progrediens PPK to better characterize this ultrarare disease and to identify its molecular etiology. Whole-exome sequencing (WES), filtering strategies, and bioinformatics analysis have been achieved.

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This study aims to analyze the epidemiological, clinical, therapeutic and evolutionary profile of ocular manifestations in patients with Behçet's disease. We conducted a retrospective, descriptive study of the medical records of 121 patients managed by specialists with expertise in this disease over a period of one year and a half between January 2015 and June 2016. The average age of patients was 35 years, 63.

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Hearing relies on mechanically gated ion channels present in the actin-rich stereocilia bundles at the apical surface of cochlear hair cells. Our knowledge of the mechanisms underlying the formation and maintenance of the sound-receptive structure is limited. Utilizing a large-scale forward genetic screen in mice, genome mapping and gene complementation tests, we identified Clrn2 as a new deafness gene.

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Cross-linking (CXL) is a technique whose design aims to achieve a specific goal: to harden the corneal tissue of eyes with a progressive form of keratoconus. Other indications are being investigated, such as treatment of infectious keratitis and prevention of corneal ectasia post corneal ablative refractive surgery. Hardening the cornea means changing its biomechanical properties.

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Clarin-1, a tetraspan-like membrane protein defective in Usher syndrome type IIIA (USH3A), is essential for hair bundle morphogenesis in auditory hair cells. We report a new synaptic role for clarin-1 in mouse auditory hair cells elucidated by characterization of Clrn1 total (Clrn1ex4-/-) and postnatal hair cell-specific conditional (Clrn1ex4fl/fl Myo15-Cre+/-) knockout mice. Clrn1ex4-/- mice were profoundly deaf, whereas Clrn1ex4fl/fl Myo15-Cre+/- mice displayed progressive increases in hearing thresholds, with, initially, normal otoacoustic emissions and hair bundle morphology.

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Usher syndrome type 1 (USH1) is a major cause of inherited deafness and blindness in humans. The eye disorder is often referred to as retinitis pigmentosa, which is characterized by a secondary cone degeneration following the rod loss. The development of treatments to prevent retinal degeneration has been hampered by the lack of clear evidence for retinal degeneration in mutant mice deficient for the Ush1 genes, which instead faithfully mimic the hearing deficit.

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The genetic, mutational and phenotypic spectrum of deafness-causing genes shows great diversity and pleiotropy. The best examples are the group of genes, which when mutated can either cause non-syndromic hearing loss (NSHL) or the most common dual sensory impairment, Usher syndrome (USH). Variants in the CIB2 gene have been previously reported to cause hearing loss at the DFNB48 locus and deaf-blindness at the USH1J locus.

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Defects of CIB2, calcium- and integrin-binding protein 2, have been reported to cause isolated deafness, DFNB48 and Usher syndrome type-IJ, characterized by congenital profound deafness, balance defects and blindness. We report here two new nonsense mutations (pGln12* and pTyr110*) in patients displaying nonsyndromic profound hearing loss, with no evidence of vestibular or retinal dysfunction. Also, the generated mice display an early onset profound deafness and have normal balance and retinal functions.

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Mutations in the gene encoding harmonin, a multi-PDZ domain-containing submembrane protein, cause Usher syndrome type 1 (congenital deafness and balance disorder, and early-onset sight loss). The structure of the protein and biological activities of its three different classes of splice isoforms (a, b, and c) remain poorly understood. Combining biochemical and biophysical analyses, we show that harmonin-a1 can switch between open and closed conformations through intramolecular binding of its C-terminal PDZ-binding motif to its N-terminal supramodule NTD-PDZ1 and through a flexible PDZ2-PDZ3 linker.

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Introduction: The goal of this study is to assess functional and aesthetic results of anterior lamellar resection with lid margin splitting of the upper lid in the treatment of cicatricial trachomatous entropion.

Patients And Methods: Descriptive cross-sectional study of a series of 26 consecutive patients treated between January 2014 and December 2015. All patients were operated for cicatricial trachomatous entropion in our tertiary center using the technique of the anterior lamellar resection with lid margin splitting of the upper eyelid.

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Usher syndrome type 1 (USH1) causes combined hearing and sight defects, but how mutations in USH1 genes lead to retinal dystrophy in patients remains elusive. The USH1 protein complex is associated with calyceal processes, which are microvilli of unknown function surrounding the base of the photoreceptor outer segment. We show that in , these processes are connected to the outer-segment membrane by links composed of protocadherin-15 (USH1F protein).

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