Publications by authors named "Abdelhak S"

Background: POLIII-related leukodystrophies are a group of recently recognized hereditary white matter diseases with a similar clinical and radiological phenotype. No Tunisian studies have been published about POLIII-related leukodystrophy due to POLR3A variants. The aim of this study was to contribute to the clinical, radiological, and genetic characterization of POLR3A-related leukodystrophy in a Tunisian cohort.

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  • The Genome Tunisia Project is a two-phase initiative (2022-2035) aimed at sequencing the Tunisian Genome and advancing personalized medicine in Tunisia, a diverse North African country affected by human migration patterns from various continents.
  • A multidisciplinary team of Tunisian experts is focused on addressing key priorities, such as determining the reference genome sequence, enhancing education and awareness, and improving infrastructure for personalized medicine integration.
  • The project involves collaboration among various stakeholders, including healthcare providers and policymakers, and aims to boost research and innovation in genomics while improving healthcare practices in the region.
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  • Autosomal recessive congenital ichthyosis (ARCI) is a rare skin condition primarily characterized by skin scaling and hair abnormalities, which are often overlooked regarding their impact on patients' quality of life.
  • This study involved clinical and trichoscopic examinations of 30 ARCI patients over three years, revealing that alopecia affects a significant number, with various patterns of hair loss documented among participants.
  • Notable trichoscopic findings included scaling and different hair types that correlate with the severity of ARCI, suggesting that hair health is a crucial component of this condition often underestimated in prior research.
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The genetic disease spectrum in Tunisia arises from the founder effect, genetic drift, selection, and consanguinity. The latter represents a deviation from panmixia, characterized by a non-random matrimonial choice that may be subject to several rules, such as socio-cultural, economic, or other factors. This shifts the genetic structure away from the Hardy-Weinberg equilibrium, increasing homozygous genotypes and decreasing heterozygotes, thus raising the frequency of autosomal recessive diseases.

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  • * A 14-year study analyzed over 700 patients with syndromic deafness (SD) in Tunisia, using advanced genetic sequencing techniques to identify various genetic conditions, including Usher syndrome and H syndrome.
  • * The research highlights challenges in distinguishing between non-syndromic and syndromic HI and reveals that nearly 50% of Tunisian SD cases relate to rare inherited metabolic disorders, providing valuable insights for improving molecular diagnoses in Tunisia and North Africa.
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Precision Medicine is being increasingly used in the developed world to improve health care. While several Precision Medicine (PM) initiatives have been launched worldwide, their implementations have proven to be more challenging particularly in low- and middle-income countries. To address this issue, the "Personalized Medicine in North Africa" initiative (PerMediNA) was launched in three North African countries namely Tunisia, Algeria and Morocco.

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  • * This study focused on analyzing genetic variations related to ADR in healthy cohorts from Tunisia (135 participants) and Italy (737 participants) through a SNP array, comparing these against data from global populations.
  • * Results indicated strong genetic similarities within Mediterranean populations but notable differences compared to other regions, identifying 27 variants with significant population differentiation that can help improve personalized medicine approaches in treating ADRs.
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Admixture mapping has been useful in identifying genetic variations linked to phenotypes, adaptation and diseases. Copy number variations (CNVs) represents genomic structural variants spanning large regions of chromosomes reaching several megabases. In this investigation, the "Canary" algorithm was applied to 102 Tunisian samples and 991 individuals from eleven HapMap III populations to genotype 1279 copy number polymorphisms (CNPs).

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  • - This study focuses on the challenges of cancer management in Africa, particularly in Tunisia, where limited resources and health system issues affect cancer care and the need for better identification of hereditary cancer syndromes.
  • - Researchers analyzed clinicopathological data from 521 patients and performed genetic testing, identifying 36 BRCA mutations associated with hereditary breast and ovarian cancer syndrome, along with other rare syndromes like Li-Fraumeni and Bloom syndrome.
  • - The findings emphasize the importance of enhancing genetic education and implementing genetic screening programs in Tunisia and other African countries to improve cancer management and reduce hereditary disease burdens.
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Recent advances in sequencing technologies have significantly increased our capability to acquire large amounts of genetic data. However, the clinical relevance of the generated data continues to be challenging particularly with the identification of Variants of Uncertain Significance (VUSs) whose pathogenicity remains unclear. In the current report, we aim to evaluate the clinical relevance and the pathogenicity of VUSs in DNA repair genes among Tunisian breast cancer families.

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Elevated rates of consanguinity and inbreeding are responsible for the high prevalence of recessively inherited diseases among inbred populations including Tunisia. In addition, the co-occurrence of two of these conditions, called also comorbidity, within the same individual or in members of the same family are often described in Tunisia which is challenging for diagnosis. The high throughput sequencing has improved the diagnosis of inherited diseases.

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Gut microbiota plays a key role in the regulation of metabolism and immunity. We investigated the profile of gut microbiota and the impact of dietary intake on gut bacterial distribution in diabetic and healthy Tunisian subjects, aiming to identify a dysbiotic condition, hence opening the way to restore eubiosis and facilitate return to health. In the present research, we enrolled 10 type 1 diabetic (T1D), 10 type 2 diabetic (T2D) patients and 13 healthy (H) subjects.

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Diabetes and hypertension are a serious public health problem worldwide. In the last decades, prevalence of these two metabolic diseases has dramatically increased in the Middle East and North Africa region, especially in Tunisia. This study aimed to determine the prevalence of type 2 diabetes (T2D) and High Blood Pressure (HBP) in Zaghouan, a North-East region of Tunisia.

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The herbicide glyphosate is contaminating a large number of freshwater ecosystems worldwide and its fate and effects remains uncertain in light of the effects of global change. The present study examines how variations in water temperature and light availability relative to global change affect the ability of stream biofilms to degrade the herbicide glyphosate. Biofilms were exposed in microcosms to two levels of water temperature simulating global warming (Ambient = 19-22 °C and Warm = 21-24 °C) and three levels of light representative of riparian habitat destruction due to land use change (Dark = 0, Intermediate = 600, High = 1200 μmol photons m s).

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Background: Xeroderma pigmentosum is an autosomal recessive disease characterized by a high sensitivity to UV radiations. The disease is clinically and genetically heterogeneous, thus making accurate early clinical diagnosis difficult. Although the disease is considered rare worldwide, previous studies have shown that it is more frequent in Maghreb countries.

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Breast cancer has different epidemio-clinical characteristics in Middle East and North-African populations compared to those reported in the Western countries. The aim of this study is to analyze the epidemiological and clinico-pathological features of breast cancer in Tunisia and to determine prognostic factors with special interest to family history, Ki-67 proliferation index and comorbidity. We retrospectively reviewed epidemiological and clinico-pathological data from patients' medical records, treated in the Medical Oncology Department at Abderrahmane Mami Hospital, in the period 2011-2015.

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  • Mitochondrial cytopathies like Leigh syndrome are genetic disorders caused by mutations in mitochondrial or nuclear DNA that disrupt energy production.
  • A study focused on diagnosing Leigh syndrome in six Tunisian children, identifying genetic variants through advanced sequencing techniques.
  • The research highlights how genomic analysis can aid in diagnosing and treating patients by using supplements for those with specific gene mutations, emphasizing the importance of understanding genetic diversity in different populations.
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Several syndromic forms of digestive cancers are known to predispose to early-onset gastric tumors such as Hereditary Diffuse Gastric Cancer (HDGC) and Lynch Syndrome (LS). LSII is an extracolonic cancer syndrome characterized by a tumor spectrum including gastric cancer (GC). In the current work, our main aim was to identify the mutational spectrum underlying the genetic predisposition to diffuse gastric tumors occurring in a Tunisian family suspected of both HDGC and LS II syndromes.

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A 4-year-old boy born from a consanguineous marriage was referred to our department for congenital ichthyosis. He was a collodion baby at birth and progressively developed a generalized erythroderma with fine whitish scales covering his body. Initially, he was diagnosed as having congenital ichthyosiform erythroderma.

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Xeroderma pigmentosum (XP) is a DNA repair disease that predisposes to early skin cancers as cutaneous melanoma. Melanoma microenvironment contains inflammatory mediators, which would be interesting biomarkers for the prognosis or for the identification of novel therapeutic targets. We used a PCR array to evaluate the transcriptional pattern of 84 inflammatory genes in melanoma tumors obtained from XP patients (XP-Mel) and in sporadic melanoma (SP-Mel) compared to healthy skin.

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A career in systems science offers exciting prospects as well as challenges around the world, which are often underexplored or unknown. Gender parity, diversity, inclusion, and equity are essential for knowledge production, systems science research, and innovation to be representative, democratic, and critically informed. By virtue of its focus on systems, omics science is ideally poised to understand and respond to systemic and structural issues that hinder gender parity, equity, and democracy in science and society.

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  • Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a serious heart condition characterized by abnormal heart rhythms and typically occurs in people who have a normal resting ECG and no structural heart issues.
  • Most cases of CPVT are linked to mutations in specific genes, but about 35% of patients don’t have an identified genetic cause, suggesting there may be more genes involved.
  • A case study of a 6-year-old boy with a CPVT phenotype and a family history of sudden cardiac death revealed genetic variants; the study proposes that these variants may contribute to the disease, indicating a need for further research on their roles.
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Significant advances have been made to understand the genetic basis of breast cancer. High, moderate and low penetrance variants have been identified with inter-ethnic variability in mutation frequency and spectrum. Genome wide association studies (GWAS) are widely used to identify disease-associated SNPs.

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