Publications by authors named "Sofia Kitsiou Tzeli"

Article Synopsis
  • Mesenchymal stromal cells (MSCs) can be derived from different sources, including pluripotent stem cells, and their properties need thorough investigation for potential clinical use.
  • This study compared the growth and cartilage-producing abilities of MSCs from human induced pluripotent stem cells (hiPSCs), embryonic stem cells (hESCs), and bone marrow (BM) samples.
  • Findings showed that while PSC-derived MSCs had significantly higher proliferation rates than BM-MSCs, they struggled to produce the desired type of cartilage (hyaline) compared to the BM-derived MSCs.
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Our comprehensive cohort of 1100 unrelated achromatopsia (ACHM) patients comprises a considerable number of cases (~5%) harboring only a single pathogenic variant in the major ACHM gene CNGB3. We sequenced the entire CNGB3 locus in 33 of these patients to find a second variant which eventually explained the patients' phenotype. Forty-seven intronic CNGB3 variants were identified in 28 subjects after a filtering step based on frequency and the exclusion of variants found in cis with pathogenic alleles.

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X-linked myotubular myopathy (XLMTM) is a rare inherited neuromuscular disorder associated with mutations in the gene on the Xq28 region. We report a severely affected girl with XLMTM, caused by maternally inherited 661 kb Xq28 microduplication identified by chromosomal microarray analysis and confirmed also on DNA from muscle biopsy with a custom-designed X-chromosome-specific microarray. X-inactivation analysis revealed a skewed inactivation pattern on the proband's muscle biopsy.

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Neurofibromatosis Type 1 (NF1) is caused by mutations of the NF1 gene. The aim of this study was to identify the genetic causes underlying the disease, attempt possible phenotype/genotype correlations and add to the NF1 mutation spectrum. A screening protocol based on genomic DNA was established in 168 patients, encompassing sequencing of all coding exons and adjoining introns using a custom targeted next generation sequencing protocol and subsequent confirmation of findings with Sanger sequencing.

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Purpose Of Review: The article provides an update on new insights of factors altering inherited maternal epigenome that ultimately affect fetal and neonatal growth.

Recent Findings: A number of new publications have identified mechanisms through which maternal nutrition, environmental exposures such as stress and toxic substances altering expression of imprinted genes during pregnancy can influence fetal and neonatal phenotype and susceptibility to disease development later in life. The possible causes of metabolic syndrome by in-utero epigenetic alterations of genes involved in energy metabolism (PPARγ and PPARα), microRNAs, arginine methyltransferases, lysine demethylases, and histone deacetylaces have been elucidated.

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Background: Retinal dystrophies are a clinically and genetically heterogeneous group of disorders which affect more than two million people worldwide. The present study focused on the role of the ABCA4 gene in the pathogenesis of hereditary retinal dystrophies (autosomal recessive Stargardt disease, autosomal recessive cone-rod dystrophy, and autosomal recessive retinitis pigmentosa) in patients of Greek origin.

Materials And Methods: Our cohort included 26 unrelated patients and their first degree healthy relatives.

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Article Synopsis
  • - Antley-Bixler syndrome (ABS) is a rare condition linked to issues with the POR gene, leading to abnormalities like craniosynostosis and steroid hormone production disorders, primarily inherited in an autosomal recessive way.
  • - This study examines three sibling fetuses diagnosed with ABS following termination of pregnancies at different gestation stages, utilizing ultrasound and postmortem evaluations combined with genetic analyses.
  • - The findings identified a combination of mutations in the POR gene — a maternal missense mutation and a paternal deletion — contributing to the development of ABS, thus providing new insights into its early manifestations that were previously underreported.
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Background: There are three distinct subtypes of Trichorhinophalangeal syndrome (TRPS); TRPS type I, TRPS type II and TRPS type III. Features common to all three subtypes include sparse, slowly growing scalp hair, laterally sparse eyebrows, a bulbous tip of the nose (pear-shaped), and protruding ears. Langer-Giedion syndrome (LGS) or TRPS type II is a contiguous gene syndrome on 8q24.

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Introduction: Mutations in the CAV3 gene are usually inherited in an autosomal dominant manner and lead to distinct disorders including limb-girdle muscular dystrophy 1C, rippling muscle disease, and isolated creatine kinase elevation.

Patients And Methods: The features of the first patients with caveolin-3 deficiency from Greece are presented. Patients' phenotypes ranged from asymptomatic creatine kinase elevation to severe weakness of lower extremities.

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Aim: To estimate the level of awareness of prenatal screening (PS) and explore the underlying demographic, lifestyle and medical history parameters of Greek and non-Greek pregnant women undergoing prenatal diagnosis.

Patients And Methods: A structured questionnaire was answered by 354 women at the time of receiving the results of invasive prenatal testing. Summary statistics and multiple logistic regression analyses were performed.

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Rare, atypical, and undiagnosed autosomal-recessive disorders frequently occur in the offspring of consanguineous couples. Current routine diagnostic genetic tests fail to establish a diagnosis in many cases. We employed exome sequencing to identify the underlying molecular defects in patients with unresolved but putatively autosomal-recessive disorders in consanguineous families and postulated that the pathogenic variants would reside within homozygous regions.

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Constitutional microdeletions affecting 3q13.2q13.31 are rare and attempts for genotype-phenotype correlations have only recently been made in a cohort of 28 patients.

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Angelman Syndrome (AS) is a neurodevelopmental disorder characterized by severe developmental delay, speech impairment and unique behaviors including inappropriate laughter and happy disposition. AS is related to deficient maternal UBE3A gene expression caused either by chromosomal deletions, uniparental disomy, molecular defects of the imprinted 15q11-q13 critical region or by loss of function mutations in the maternally inherited UBE3A. In the present study, screening UBE3A was performed in 43 patients who were referred for AS but whom previous molecular diagnostic tests failed to provide a diagnosis.

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High resolution oligonucleotide array Comparative Genome Hybridization technology (array-CGH) has greatly assisted the recognition of the 1p36 contiguous gene deletion syndrome. The 1p36 deletion syndrome is considered to be one of the most common subtelomeric microdeletion syndromes and has an incidence of ~1 in 5000 live births, while respectively the "pure" 1p36 microduplication has not been reported so far. We present seven new patients who were referred for genetic evaluation due to Developmental Delay (DD), Mental Retardation (MR), and distinct dysmorphic features.

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Clinical characteristics of patients are not always related to specific syndromes. Array-comparative genomic hybridization (aCGH) is used to detect submicroscopic copy number variants within the genome not visible by conventional karyotyping. The clinical application of aCGH has helped the genetic diagnosis of patients with unexplained developmental delay/intellectual disability, autism spectrum disorders, with or without multiple congenital anomalies.

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Purpose: Telomerase activity (TA), frequently observed in cancer, compensates for telomere shortening thus preventing cell senescence and conferring resistance to therapy. In the present study, we investigated the expression of human telomerase reverse transcriptase (hTERT) and TA and their regulation, as well as apoptotic rates and correlation with the presence of human epidermal growth factor receptor 2 (HER2), in irradiated tumour-derived breast cancer cells.

Materials And Methods: In 50 breast cancer tissue samples hTERT mRNA expression and TA were correlated with cell features (HER2, Estrogen and Progesterone Receptor status).

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Mutations in the Wilms' tumor suppressor gene 1 (WT1), most commonly within exons 8 or 9 or intron 9, are found in cases with the overlapping conditions of Denys-Drash and Frasier syndromes, as well as in patients with steroid-resistant nephrotic syndrome (SRNS). This study investigated the presence of WT1 gene mutations in cases with childhood SRNS, along with an evaluation of their clinical outcome. Twenty-seven Greek children with sporadic (19 cases) and familial (8 cases) SRNS were tested.

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Background: Deletions of chromosome 22q11 are present in over 90% of cases of DiGeorge or Velo-Cardio-Facial syndrome (DGS/VCFS). 15q11-q13 duplication is another recognized syndrome due to rearrangements of several genes, belonging to the category of imprinted genes. The phenotype of this syndrome varies but has been clearly associated with developmental delay and autistic spectrum disorders.

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