Publications by authors named "Kibar Z"

Congenital scoliosis (CS) is a type of vertebral malformation for which the etiology remains elusive. The notochord is pivotal for vertebrae development, but its role in CS is still understudied. Here, we generated a zebrafish knockout of ptk7a, a planar cell polarity (PCP) gene that is essential for convergence and extension (C&E) of the notochord, and detected congenital scoliosis-like vertebral malformations (CVMs).

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  • Meningomyelocele is a serious neural tube defect and the most common structural birth defect affecting the central nervous system.
  • The Spina Bifida Sequencing Consortium found that deletions on chromosome 22q11.2 increase the risk of meningomyelocele by 23 times compared to the general population.
  • Research indicates that the deletion of specific genes in this region, combined with a lack of maternal folate, can significantly increase the risk of neural tube defects in offspring.
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  • - Congenital hypothyroidism due to thyroid dysgenesis (NS-CHTD) is a largely sporadic condition with a higher risk among first-degree relatives, but shows high discordance in identical twins, hinting at a complex genetic and environmental interaction.
  • - Researchers conducted a study using whole-exome sequencing (WES) to discover potential new genes responsible for NS-CHTD by comparing affected individuals with unaffected controls, focusing on rare protein-altering variants.
  • - Despite not finding new predisposing genes, the study identified that 42% of NS-CHTD cases contained rare variants in known congenital hypothyroidism genes, with some cases having multiple gene variants but no significant differences in severity between groups. *
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Ribosome dysfunction is implicated in multiple abnormal developmental and disease states in humans. Heterozygous germline mutations in genes encoding ribosomal proteins are found in most individuals with Diamond-Blackfan anemia (DBA), whereas somatic mutations have been implicated in a variety of cancers and other disorders. Ribosomal protein-deficient animal models show variable phenotypes and penetrance, similar to human patients with DBA.

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This study presents a methodology to predict the child poverty impact of COVID-19 that can be readily applied in other country contexts where similar household data are available-and illustrates this case using data from Turkey. Using Household Budget Survey 2018, the microsimulation model estimates the impact of labour income loss on household expenditures, considering that some types of jobs/sectors may be more vulnerable than others to the COVID-19 shock. Labour income loss is estimated to lead to reductions in monthly household expenditure using an income elasticity model, and expenditure-based child poverty is found to increase in Turkey by 4.

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  • - Three siblings from Somalia have severe congenital hypothyroidism, and exome sequencing revealed a specific genetic variant affecting a thyroid-related protein isoform.
  • - The identified mutation leads to the creation of a pseudoexon in isoform 1, which is important for thyroid function, disrupting the production of a protein that should normally be present at the cell surface.
  • - This study emphasizes the importance of understanding genetic isoforms and disease biology in exome analysis, marking the first report of a deep intronic mutation that inactivates the thyroid stimulating hormone (TSH) receptor.
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Neural tube defects (NTDs), including spina bifida and anencephaly, represent the most severe and common malformations of the central nervous system affecting 0.7-3 per 1000 live births. They result from the failure of neural tube closure during the first few weeks of pregnancy.

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  • * A whole exome sequencing study was conducted on several families with NTDs, combining new data with previously collected data to identify genetic variants linked to these defects.
  • * The study found four new loss-of-function variants in genes associated with NTD and highlighted a potential new candidate gene, MYO1E, suggesting advancements in understanding the genetic causes of NTD through next-generation sequencing.
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Background: Syringomyelia (SM) is a common condition affecting brachycephalic toy breed dogs and is characterized by the development of fluid-filled cavities within the spinal cord. It is often concurrent with a complex developmental malformation of the skull and craniocervical vertebrae called Chiari-like malformation (CM) characterized by a conformational change and overcrowding of the brain and cervical spinal cord particularly at the craniocervical junction. CM and SM have a polygenic mode of inheritance with variable penetrance.

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  • The study investigates the effectiveness of whole-exome sequencing (WES) in diagnosing fetal anomalies, a type of developmental disorder that is not well understood.
  • Researchers conducted WES on 101 fetuses or stillborns with severe anomalies and found a molecular diagnosis in 19 cases, many of which were previously unsuspected by clinicians due to atypical presentations.
  • The findings reveal new genetic insights, including likely pathogenic variants and novel genes associated with severe conditions, emphasizing both the potential and challenges of using WES for prenatal diagnosis.
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  • Developmental and epileptic encephalopathy (DEE) combines epilepsy and intellectual disability, often leading to developmental stagnation or decline, with unknown causes in most cases.
  • Researchers conducted whole-genome sequencing on 197 DEE patients and their healthy parents to identify new genetic mutations linked to the condition.
  • They established a molecular diagnosis for 32% of the individuals, finding that de novo point mutations were the primary cause, suggesting a unique genetic profile for DEE compared to intellectual disability without epilepsy.
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Planar cell polarity (PCP) signaling controls a number of morphogenetic processes including convergent extension during gastrulation and neural tube formation. Defects in this pathway cause neural tube defects (NTD), the most common malformations of the central nervous system. The Looptail (Lp) mutant mouse was the first mammalian mutant implicating a PCP gene (Vangl2) in the pathogenesis of NTD.

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The objective of the present study is to describe a cohort of complex esophageal atresia and the yield of genetic tests performed for such patients. We selected 45 patients with complex esophageal atresia (EA), namely those having at least one associated anomaly. We reviewed their medical records to assess clinical features, other diagnoses, and genetic investigations.

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Chiari malformation type I (CMI) is a congenital abnormality of the cranio-cerebral junction with an estimated incidence of 1 in 1280. CMI is characterized by underdevelopment of the occipital bone and posterior fossa (PF) and consequent cerebellar tonsil herniation. The presence for a genetic basis to CMI is supported by many lines of evidence.

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Scribble1 (Scrib1) is a tumor suppressor gene that has long been established as an essential component of apicobasal polarity (ABP). In mouse models, mutations in Scrib1 cause a severe form of neural tube defects (NTDs) as a result of a defective planar cell polarity (PCP) signaling. In this study, we dissected the role of Scrib1 in the pathogenesis of NTDs in its mouse mutant Circletail (Crc), in cell lines and in a human NTD cohort.

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Neural tube defects, including spina bifida, are among the most common birth defects caused by failure of neural tube closure during development. They have a complex etiology involving largely undetermined environmental and genetic factors. Previous studies in mouse models have implicated the transcription factor Grhl3 as an important factor in the pathogenesis of spina bifida.

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Objectives: To characterise the symptomatic phenotype of Chiari-like malformation (CM), secondary syringomyelia (SM) and brachycephaly in the Cavalier King Charles Spaniel using morphometric measurements on mid-sagittal Magnetic Resonance images (MRI) of the brain and craniocervical junction.

Methods: This retrospective study, based on a previous quantitative analysis in the Griffon Bruxellois (GB), used 24 measurements taken on 130 T1-weighted MRI of hindbrain and cervical region. Associated brachycephaly was estimated using 26 measurements, including rostral forebrain flattening and olfactory lobe rotation, on 72 T2-weighted MRI of the whole brain.

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Retinoic acid (RA) signaling plays a key role in the development and function of several systems in mammals. We previously discovered that the de novo mutations c.1159C>T (p.

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Background: Recently, biallelic mutations in the Neuroblastoma Amplified Sequence NBAS gene have been identified in ten patients that present recurrent acute liver failure (RALF) in early infancy. In addition to severe liver dysfunction, some of these individuals also suffered from other comorbidities including cardiomyopathy, neurologic phenotypes and gastrointestinal immune defects. Here we report on a consanguineous Lebanese family with three siblings affected by RALF.

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Background: Neural tube defects (NTDs) are among the most common congenital defects affecting approximately 1 in 1000 live births in North America. Their etiology is complex including environmental and genetic factors. Defects in the planar cell polarity (PCP) signaling pathway have been strongly associated with NTDs in animal models and human cohorts.

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Background: Neural tube defects (NTDs) are very common and severe birth defects that are caused by failure of neural tube closure and that have a complex aetiology. Anencephaly and spina bifida are severe NTDs that affect reproductive fitness and suggest a role for de novo mutations (DNMs) in their aetiology.

Methods: We used whole-exome sequencing in 43 sporadic cases affected with myelomeningocele or anencephaly and their unaffected parents to identify DNMs in their exomes.

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Background: Neural Tube Defects (NTD) are a common class of birth defects that occur in approximately 1 in 1000 live births. Both genetic and nongenetic factors are involved in the etiology of NTD. Planar cell polarity (PCP) genes plays a critical role in neural tube closure in model organisms.

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Background: Planar cell polarity (PCP) is a major branch of Wnt signaling that controls the process of convergent extension in gastrulation and neurulation. PCP defects were associated with neural tube defects (NTDs) that are the most common central nervous system anomalies. PCP signaling is highly dosage sensitive and exhibits an antagonistic relationship with the canonical Wnt/β-catenin pathway.

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Neural Tube Defects (NTDs) are congenital malformations that involve failure of the neural tube closure during the early phases of development at any level of the rostro-caudal axis. The planar cell polarity (PCP) pathway is a highly conserved, noncanonical Wnt-Frizzled-Dishevelled signaling cascade, that was first identified in the fruit fly Drosophila. We are here reviewing the role of the PCP pathway genes in the etiology of human NTDs, updating the list of the rare and deleterious mutations identified so far.

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