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Siala O.,Laboratoire Of Genetique Moleculaire Humaine | Belguith N.,Laboratoire Of Genetique Medicale | Fakhfakh F.,Laboratoire Of Genetique Moleculaire Humaine
Iranian Journal of Pediatrics | Year: 2013

Background: Peters Plus syndrome (MIM 261540) is a rare autosomal recessive condition characterized by ocular defects (typically Peters anomaly) and other systemic major/minor abnormalities. Mutations in the B3GALTL gene encoding the β-1,3-glucosyltransferase have been found in virtually all patients with typical Peters Plus syndrome. Case Presentation: We report here a female patient with severe manifestations of Peters Plus syndrome including facial dysmorphism and bilateral corneal opacity associated with left renal pyelo-calicial dilatation and sexual ambiguity. Total sequencing of the B3GALTL gene revealed no mutation in the patient. Conclusion: To our knowledge, sexual ambiguity has not previously been reported in Peters Plus syndrome so far, and renal malformation is also apparently rare in the syndrome. © 2013 by Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, All rights reserved. Source

Siala O.,Laboratoire Of Genetique Moleculaire Humaine | Fakhfakh F.,Laboratoire Of Genetique Moleculaire Humaine
Gene | Year: 2014

Gene expression is initiated by the binding of transcription factors to cis-regulatory modules such as enhancer elements binding to the Serine/Arginine proteins. Recently, we noticed an increased ability to identify the location as well as the motifs of enhancers using genome-wide information on spliceosomal factor occupancy, cofactor recruitment and chromatin modifications. In this study, we have undertaken a large-scale genomic analysis in an attempt to uncover if the exonic splicing enhancer motif binding to the SC35 and the SRp40 SR proteins is conserved among several groups of human genes. For the SRp40, the results showed that the ESE consensus is conserved among human genes. Concerning the SC35 SR protein, results showed an ESE motif conserved among human tissues and between different levels of muscular cell differentiation and within the same chromosome. However, this motif displays subtle discrepancies between genes localized in different chromosomes. These results emphasize the presence of different translational isoforms of the SFRS2 gene encoding for the SC35, or different post-translational protein maturations in different chromosomes, confirming that chromatin structure is another layer of gene regulation. These links between chromatin pattern and splicing give further mechanistic support to functional interconnections between splicing, transcription and chromatin structure, and raise the intriguing possibility of the existence of a memory for splicing patterns to be inherited through epigenetic modifications. © 2014 Elsevier B.V. Source

Fendri-Kriaa N.,Laboratoire Of Genetique Moleculaire Humaine | Mkaouar-Rebai E.,Laboratoire Of Genetique Moleculaire Humaine | Moalla D.,Laboratoire Of Genetique Moleculaire Humaine | Belguith N.,Laboratoire Of Genetique Moleculaire Humaine | And 5 more authors.
Journal of Child Neurology | Year: 2010

Rett syndrome is a severe disorder characterized by loss of acquired skills after a period of normal development in infant girls. It is caused mainly by mutations in the MECP2 gene. In this study, we reported mutations in the MECP2 gene in 7 Tunisian patients with classic Rett syndrome. The results showed the presence of a double mutation in 1 patient: p.R306C and c.1461+98insA, which create a new hypothetical polyadenylation site in the 3 ĝ€2UTR of the MECP2 gene. We also detected in another patient a new variant c.1461+92C>G in the 3ĝ€2UTR located previous to 34 bp from the polyadenylation site with a score of 4.085. This variation is located in a hypothetical splicing enhancer with a score of 1.96277 according to the ESE finder program. In the remaining 5 patients, we found 2 common mutations: p.T158M in 4 individuals and p.R168X in only 1 girl. © The Author(s) 2010. Source

Mkaouar-Rebai E.,Laboratoire Of Genetique Moleculaire Humaine | Ellouze E.,Service de Neurologie Infantile | Chamkha I.,Laboratoire Of Genetique Moleculaire Humaine | Kammoun F.,Service de Neurologie Infantile | And 2 more authors.
Journal of Child Neurology | Year: 2011

Cytochrome c oxidase is an essential component of the mitochondrial respiratory chain that catalyzes the reduction of molecular oxygen by reduced cytochrome c. In this study, the authors report the second mutation associated with Leigh syndrome in the blood and buccal mucosa of 2 affected members of a Tunisian family. It was a novel heteroplasmic missense mitochondrial mutation at nucleotide 9478 in the gene specifying subunit III of cytochrome c oxidase substituting the valine at position 91 to alanine in a highly conserved amino acid. It was found with a high mutant load in tissues derived from endoderm (buccal mucosa) and mesoderm (blood). However, it was nearly absent in tissue derived from ectoderm (hair follicles). It was absent in 120 healthy controls, and PolyPhen analysis showed that the hydropathy index changed from +1.276 to +0.242, and the number of structures of the 3D protein decreased from 39 to 32. © The Author(s) 2011. Source

Siala O.,Laboratoire Of Genetique Moleculaire Humaine | Belguith N.,Laboratoire Of Genetique Medicale | Kammoun H.,Laboratoire Of Genetique Medicale | Kammoun B.,Service dOphtalmologie | And 4 more authors.
Gene | Year: 2012

Peters plus syndrome is an autosomal recessive rare disorder comprising ocular anterior segment dysgenesis, short stature, hand abnormalities, distinctive facial features, and often other major/minor additional defects. Peters plus syndrome is related to mutations in the B3GALTL gene with only seven recently reported mutations, leading to the inactivation of the B1, 3-glucosyltransferase. In this study, we screened the B3GALTL gene in two unrelated patients with typical Peters plus syndrome. A novel homozygous c.597-2A > G mutation was identified in both patients. Bioinformatic analyses showed that this mutation modulates the pre mRNA secondary structure of the gene, and decreases the score value related to the formation of splicing loops. Moreover, the c.597-2A > G mutation is located in a CpG Island of the B3GALTL gene, suggesting a potential epigenetic role of this position including gene's methylation and regulation. These data confirm an important role of the B3GALTL gene test that provides diagnosis confirmation and improves genetic counseling for the families. © 2012 Elsevier B.V. Source

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