Publications by authors named "Tala S"

Article Synopsis
  • Brain development involves the coordinated growth of structures necessary for forming neural circuits, with the corpus callosum being a crucial connection between brain hemispheres.
  • Defects in the growth process, particularly in the development of callosal projection neurons, can lead to syndromic corpus callosum dysgenesis (CCD) and are associated with other conditions like microcephaly.
  • The study identifies WDR47 as a key gene responsible for survival of callosal neurons and highlights its role in mitochondrial and microtubule maintenance, suggesting that mutations in this gene lead to a new neurodevelopmental syndrome involving corpus callosum abnormalities.
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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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Thrombopoietin (THPO) is a regulator of megakaryopoiesis and thrombopoiesis. Mutation of the gene is known to cause congenital amegakaryocytic thrombocytopenia (CAMT2), which is a rare inherited disorder characterized by early infancy thrombocytopenia and absent or decreased megakaryocytes with gradual progression to pancytopenia. We report the case of a Saudi girl who had been asymptomatic until age seven when she was found to have unexplained thrombocytopenia.

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Leukocyte adhesion deficiency-III (LAD-III) is a rare recessive autosomal disorder characterized by bleeding syndrome of Glanzmann-type and life-threatening infections. The main etiology of this condition is variations in the gene, which encodes kindlin-3, an integrin-binding protein. This protein is responsible for the activation of fibrinogen receptors and integrin-mediated hematopoietic cell adhesion.

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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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gene encodes for Filamin-C (FLNC) protein, a sacromeric protein with important structural and signaling functions in the myocyte. Pathogenic dominant variants in were initially linked to myofibrillar myopathy and over time, evidence showed association of this gene with different forms of autosomal dominant cardiomyopathy including hypertrophic, dilated and restrictive forms. Recently, two cases of recessive mutations have been reported by Reinstein et al.

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Congenital hypothyroidism (CH) may have major detrimental effects on growth and neurological development, but early intervention leads to excellent outcomes. CH is classified as transient or permanent, primary or secondary, with primary CH being the most common neonatal endocrine disorder. Most patients with CH do not present any typical signs and symptoms of hypothyroidism shortly after birth, partly due to transplacental maternal thyroid hormone transfer and residual neonatal thyroid function.

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Interleukin 12 receptor beta 1 (IL12Rβ1) deficiency is the most common cause of Mendelian susceptibility to mycobacterial disease (MSMD). MSMD usually predisposes the affected individuals to infections with weakly virulent mycobacteria such as Bacille Calmette-Guérin (BCG), environmental mycobacteria, non-typhoidal Salmonella, and certain other intracellular pathogens. MSMD usually presents with disseminated BCG infection after exposure to the BCG vaccine.

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Factor X (FX) deficiency is an extremely rare autosomal recessive inherited coagulation defect. We report a case of congenital Factor X-Riyadh deficiency discovered during a routine workup before a dental procedure. During routine work-up for dental surgery, prothrombin time (PT) and the international normalized ratio (INR) were prolonged.

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Article Synopsis
  • Primary mitochondrial diseases stem from issues with oxidative phosphorylation, leading to diverse genetic and clinical manifestations.
  • Researchers discovered a link between biallelic pathogenic variants in the COX11 gene and infantile-onset mitochondrial encephalopathies in two families, highlighting its previously unknown role in human disease.
  • Functional studies confirmed that cells with mutated COX11 had lower ATP levels, which could be boosted by coenzyme Q supplementation, indicating a potential treatment avenue for affected patients.
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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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Spinal muscular atrophy (SMA) with respiratory distress type 1 (SMARD1) is an exceptionally rare type of SMA. It results from disintegration of alpha motor neurons of the spinal cord. Clinically, children affected with this disorder present between the age of six weeks to six months with respiratory distress and hypotonia.

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Rahman syndrome (RMNS) is a rare genetic disorder characterized by mild to severe intellectual disability, hypotonia, anxiety, autism spectrum disorder, vision problems, bone abnormalities and dysmorphic facies. RMNS is caused by de novo heterozygous mutations in the histone linker gene H1-4; however, mechanisms underlying impaired neurodevelopment in RMNS are not understood. All reported mutations associated with RMNS in H1-4 are small insertions or deletions that create a shared frameshift, resulting in a H1.

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Aim: To extract and identify the non-polar entities from the leaves of Carica papaya, a plant used for medicinal purpose as folk medicine.

Materials And Methods: Petroleum ether extract of the Carica papaya leaves was used for this study. Saponification process and methylation process was performed to separate fatty acids and unsaponifiable matters.

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Article Synopsis
  • Human 4-hydroxyphenylpyruvate dioxygenase-like (HPDL) is an iron-containing non-heme oxygenase linked to various neurological disorders in 34 individuals from 25 families with biallelic HPDL variants.
  • These neurological disorders presented as conditions ranging from juvenile-onset spastic paraplegia to infantile-onset spasticity, often accompanied by severe developmental delays and respiratory issues.
  • Experiments showed that HPDL is expressed in the nervous system, plays a role in motor function in zebrafish models, and its variants disrupt enzymatic function, suggesting a causative link between HPDL mutations and neurological diseases.
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Background: Loop diuretics are used for congestion relief, and dose adaptations are usually a consequence of the clinicians' clinical judgement about the congestive status of the patient. In EPHESUS (Eplerenone in Patients With Systolic Dysfunction After Myocardial Infarction), many patients required diuretics for congestion relief. We thus hypothesized that blinded allocation to eplerenone would lead clinicians to reduce loop diuretics, as a consequence of the improvement in patients' status.

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Purpose: Epileptic encephalopathies (EE), are a group of age-related disorders characterized by intractable seizures and electroencephalogram (EEG) abnormalities that may result in cognitive and motor delay. Early infantile epileptic encephalopathies (EIEE) manifest in the first year of life. EIEE are highly heterogeneous genetically but a genetic etiology is only identified in half of the cases, typically in the form of de novo dominant mutations.

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Defects in the peroxisomes biogenesis and/or function result in peroxisomal disorders. In this study, we describe the largest Arab cohort to date (72 families) of clinically, biochemically and molecularly characterized patients with peroxisomal disorders. At the molecular level, we identified 43 disease-causing variants, half of which are novel.

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Purpose: Establishing links between Mendelian phenotypes and genes enables the proper interpretation of variants therein. Autozygome, a rich source of homozygous variants, has been successfully utilized for the high throughput identification of novel autosomal recessive disease genes. Here, we highlight the utility of the autozygome for the high throughput confirmation of previously published tentative links to diseases.

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Article Synopsis
  • The study investigates congenital microcephaly (CM), a significant birth defect linked to long-term neurological issues, by analyzing the clinical and genetic profiles of patients with Mendelian forms of the condition.
  • Researchers assessed 150 patients from 104 families, identifying 56 Mendelian forms of CM, discovering a minimal overlap with genetic causes of postnatal microcephaly and highlighting the complex relationship between primary microcephaly and primordial dwarfism.
  • The findings include the identification of 37 new likely disease-causing variants and the confirmation and suggestion of several candidate genes, enhancing the understanding of CM's genetic diversity and aiding in the evaluation of affected children.
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Article Synopsis
  • The study investigates a large group of 411 patients from 288 families with skeletal dysplasia, focusing on their genetic information.
  • It finds 224 potentially harmful genetic variations in 123 related genes, including five that may be significant for the disease, and identifies both established and new phenotypic categories of skeletal dysplasia.
  • The research highlights a higher-than-average disease burden in their population and aims to enhance the diagnosis of skeletal dysplasia by broadening our understanding of its phenotypic and genetic diversity.
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β-Defensin 3 (BD3) was identified as a ligand for the melanocortin receptors (MCRs) in 2007, although the pharmacology activity of BD3 has not been clearly elucidated. Herein, it is demonstrated that human BD3 and mouse BD3 are full micromolar agonists at the MCRs. Furthermore, mouse β-defensin 1 (BD1) and human BD1 are also MCR micromolar agonists.

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