Publications by authors named "Shamseldin H"

Background: Founder variants are ancestral variants shared by individuals who are not closely related. The large effect size of some of these variants in the context of Mendelian disorders offers numerous precision medicine opportunities.

Methods: Using one of the largest datasets on Mendelian disorders in the Middle East, we identified 2,908 medically relevant founder variants derived from 18,360 exomes and genomes and investigated their contribution to the clinical annotation of the human genome.

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Combined oxidative phosphorylation deficiency (COXPD) is a rare multisystem disorder which is clinically and genetically heterogeneous. Genome sequencing identified biallelic variants in individuals from five unrelated families with presentations ranging from Perrault syndrome (primary ovarian insufficiency and sensorineural hearing loss) to severe childhood onset of leukodystrophy, learning disability, microcephaly and retinal dystrophy. Complexome profiling of fibroblasts from affected individuals revealed reduced levels of the small and, a more pronounced reduction of, the large mitochondrial ribosomal subunits.

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Background: Genetic disorders account for a large percentage of admissions and outpatient visits to children's hospitals around the world. Clinical exome sequencing (CES) is a valuable diagnostic tool in the workup of these disorders; however, it is not routinely requested by general pediatricians. This may represent a missed opportunity to increase patient access to this powerful diagnostic tool.

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Primary familial brain calcification (PFBC) is characterized by calcium deposition in the brain, causing progressive movement disorders, psychiatric symptoms, and cognitive decline. PFBC is a heterogeneous disorder currently linked to variants in six different genes, but most patients remain genetically undiagnosed. Here, we identify biallelic NAA60 variants in ten individuals from seven families with autosomal recessive PFBC.

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Article Synopsis
  • Increasing control of canine leishmaniosis (CanL) is crucial due to its zoonotic nature and the impact of climate change on disease vectors.
  • The study evaluated different serological diagnostic methods for CanL in Croatia and Brazil, comparing the performance of IFAT and the VetLine Leishmania ELISA to various rKLi8.3-based tests.
  • rKLi8.3-based tests showed superior diagnostic performance, particularly in symptomatic dogs, while the lateral flow test (LFT) provided a rapid and specific diagnosis without cross-reacting with other canine pathogens.
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ALDH1L2, a mitochondrial enzyme in folate metabolism, converts 10-formyl-THF (10-formyltetrahydrofolate) to THF (tetrahydrofolate) and CO. At the cellular level, deficiency of this NADP-dependent reaction results in marked reduction in NADPH/NADP ratio and reduced mitochondrial ATP. Thus far, a single patient with biallelic ALDH1L2 variants and the phenotype of a neurodevelopmental disorder has been reported.

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Perinatal stroke is associated with significant short- and long-term morbidity and has been recognized as the most common cause of cerebral palsy in term infants. The diagnosis of presumed perinatal stroke (PPS) is made in children who present with neurological deficit and/or seizures attributable to focal chronic infarction on neuroimaging and have uneventful neonatal history. The underlying mechanism of presumed perinatal stroke remains unknown and thorough investigation of potential monogenic causes has not been conducted to date.

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Article Synopsis
  • Long-read whole genome sequencing (lrWGS) shows promise for diagnosing autosomal recessive diseases that exome sequencing fails to identify, as tested on a cohort of 34 families.
  • In this study, likely causal variants were found in 13 families (38%), revealing novel candidate genes linked to conditions like neonatal lactic acidosis and neurodevelopmental disorders.
  • The results indicate that while lrWGS can uncover complex genetic factors, there are still important interpretation challenges that need to be addressed to fully leverage this technology for genetic diagnosis.
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Lung targeting was developed by synthesising pyrazolone derivatives 6a-f under solvent-free and thermal conditions by reacting azo coumarins 4a-c with hydrazines 5a and b using maltose as a biodegradable catalyst. Different spectral data characterized the synthesized agents as proton-NMR, FT-IR, and mass spectra. Direct radioiodination with iodine-131 was performed and optimized to reach the highest radiochemical purities (92 ± 0.

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Article Synopsis
  • DBR1 is vital for lariat debranching and its deficiency leads to a severe immune disorder resulting in pediatric brainstem viral-induced encephalitis.
  • A specific variant in DBR1 has been linked to a new allelic disorder observed in four families, characterized by prematurity, severe growth issues, skin abnormalities, and high infant mortality.
  • Research on patient fibroblast cells revealed unique RNA changes and decreased DBR1 protein levels, suggesting this new disorder differs from the known encephalitis susceptibility associated with DBR1 deficiency.
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Article Synopsis
  • Many Mendelian disease patients still lack identified pathogenic variants despite extensive data-sharing efforts, signaling a need for better variant interpretation.
  • *In a study of 4577 families, various challenges in identifying and interpreting novel variants were identified, including issues related to phenotype, pedigree structure, positional mapping, gene assertions, and complex inheritance patterns.
  • *By tackling these non-sequencing challenges, researchers estimated a potential 71% increase in diagnostic success, achieving a 54.5% identification rate of causal variants in previously undiagnosed cases.*
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Migraine is a disabling neurovascular polygenic disorder affecting life quality with escorted socioeconomic encumbrances. Herein, we investigated the consolidated amalgamation of passive lipomer approach alongside active sonophoresis assisted transdermal delivery of zolmitriptan (ZT) using high frequency ultrasound pre-treatment protocol to mitigate migraine attacks. A modified nanoprecipitation technique was utilized to prepare zolmitriptan loaded lipomers (ZTL) adopting 2 factorial design.

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Objective: Fetal megacystis generally presents as suspected lower urinary tract obstruction (LUTO), which is associated with severe perinatal morbidity. Genetic etiologies underlying LUTO or a LUTO-like initial presentation are poorly understood. Our objectives are to describe single gene etiologies in fetuses initially ascertained to have suspected LUTO and to elucidate genotype-phenotype correlations.

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SLC4A10 is a plasma-membrane bound transporter that utilizes the Na+ gradient to drive cellular HCO3- uptake, thus mediating acid extrusion. In the mammalian brain, SLC4A10 is expressed in principal neurons and interneurons, as well as in epithelial cells of the choroid plexus, the organ regulating the production of CSF. Using next generation sequencing on samples from five unrelated families encompassing nine affected individuals, we show that biallelic SLC4A10 loss-of-function variants cause a clinically recognizable neurodevelopmental disorder in humans.

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Zolmitriptan (ZT) is a potent second generation triptan, commonly administered to alleviate migraine attacks. ZT suffers various limitations; massive hepatic first pass metabolism, P-gp efflux transporters susceptibility, and limited (≈40%) oral bioavailability. Transdermal route of administration could be explored to enhance its bioavailability.

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Visceral leishmaniasis (VL) is caused by protozoan parasites of the Leishmania donovani complex and is one of the most prominent vector-borne infectious diseases with epidemic and mortality potential if not correctly diagnosed and treated. East African countries suffer from a very high incidence of VL, and although several diagnostic tests are available for VL, diagnosis continues to represent a big challenge in these countries due to the lack of sensitivity and specificity of current serological tools. Based on bioinformatic analysis, a new recombinant kinesin antigen from Leishmania infantum (rKLi8.

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Ichthyosis is a genetically heterogeneous genodermatosis characterized by severely rough, dry and scaly skin. We report two consanguineous families with congenital ichthyosis. Combined positional mapping and exome sequencing of the two families revealed novel homozygous likely deleterious variants in PRSS8 (encoding prostasin) within a linkage locus on chromosome 16.

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Background: Protozoan parasites are known to attach specific and diverse group of proteins to their plasma membrane via a GPI anchor. In malaria parasites, GPI-anchored proteins (GPI-APs) have been shown to play an important role in host-pathogen interactions and a key function in host cell invasion and immune evasion. Because of their immunogenic properties, some of these proteins have been considered as malaria vaccine candidates.

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Purpose: Brain monoamine vesicular transport disease is an infantile-onset movement disorder that mimics cerebral palsy. In 2013, the homozygous SLC18A2 variant, p.Pro387Leu, was first reported as a cause of this rare disorder, and dopamine agonists were efficient for treating affected individuals from a single large family.

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Background: The intestinal microbiota fundamentally guides the development of a normal intestinal physiology, the education, and functioning of the mucosal immune system. The Citrobacter rodentium-carrier model in germ-free (GF) mice is suitable to study the influence of selected microbes on an otherwise blunted immune response in the absence of intestinal commensals.

Results: Here, we describe that colonization of adult carrier mice with 14 selected commensal microbes (OMM + MC) was sufficient to reestablish the host immune response to enteric pathogens; this conversion was facilitated by maturation and activation of the intestinal blood vessel system and the step- and timewise stimulation of innate and adaptive immunity.

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The urgent need for vaccines against Ebola virus (EBOV) was underscored by the large outbreak in West Africa (2014-2016). Since then, several promising vaccine candidates have been tested in pre-clinical and clinical studies. As a result, two vaccines were approved for human use in 2019/2020, of which one includes a heterologous adenovirus/Modified Vaccinia virus Ankara (MVA) prime-boost regimen.

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Covalent tRNA modifications play multi-faceted roles in tRNA stability, folding, and recognition, as well as the rate and fidelity of translation, and other cellular processes such as growth, development, and stress responses. Mutations in genes that are known to regulate tRNA modifications lead to a wide array of phenotypes and diseases including numerous cognitive and neurodevelopmental disorders, highlighting the critical role of tRNA modification in human disease. One such gene, THUMPD1, is involved in regulating tRNA N4-acetylcytidine modification (ac4C), and recently was proposed as a candidate gene for autosomal-recessive intellectual disability.

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Background: Biallelic loss-of-function variants have hitherto been linked to mitochondrial complex I deficiency presenting with heterogeneous clinical and radiological features in nine cases only.

Objectives: To fully characterize, both phenotypically and genotypically, -related mitochondrial disease.

Methods: We collected data from cases identified by screening genetic databases of several laboratories worldwide and systematically reviewed the literature.

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