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Xiao X.,Case Western Reserve University | Yuan J.,Case Western Reserve University | Haik S.,University Pierre and Marie Curie | Cali I.,Case Western Reserve University | And 16 more authors.
PLoS ONE | Year: 2013

The four glycoforms of the cellular prion protein (PrPC) variably glycosylated at the two N-linked glycosylation sites are converted into their pathological forms (PrPSc) in most cases of sporadic prion diseases. However, a prominent molecular characteristic of PrPSc in the recently identified variably protease-sensitive prionopathy (VPSPr) is the absence of a diglycosylated form, also notable in familial Creutzfeldt-Jakob disease (fCJD), which is linked to mutations in PrP either from Val to Ile at residue 180 (fCJDV180I) or from Thr to Ala at residue 183 (fCJDT183A). Here we report that fCJDV180I, but not fCJDT183A, exhibits a proteinase K (PK)-resistant PrP (PrPres) that is markedly similar to that observed in VPSPr, which exhibits a five-step ladder-like electrophoretic profile, a molecular hallmark of VPSPr. Remarkably, the absence of the diglycosylated PrPres species in both fCJDV180I and VPSPr is likewise attributable to the absence of PrPres glycosylated at the first N-linked glycosylation site at residue 181, as in fCJDT183A. In contrast to fCJDT183A, both VPSPr and fCJDV180I exhibit glycosylation at residue 181 on di- and monoglycosylated (mono181) PrP prior to PK-treatment. Furthermore, PrPV180I with a typical glycoform profile from cultured cells generates detectable PrPres that also contains the diglycosylated PrP in addition to mono- and unglycosylated forms upon PK-treatment. Taken together, our current in vivo and in vitro studies indicate that sporadic VPSPr and familial CJDV180I share a unique glycoform-selective prion formation pathway in which the conversion of diglycosylated and mono181 PrPC to PrPSc is inhibited, probably by a dominant-negative effect, or by other co-factors. © 2013 Xiao et al.


Grigorescu-Sido P.,University of Medicine and Pharmacy, Cluj-Napoca | Popp R.,University of Medicine and Pharmacy, Cluj-Napoca | Legendre M.,U.F. de Genetique Moleculaire | Amselem S.,U.F. de Genetique Moleculaire | And 3 more authors.
Journal of Pediatric Endocrinology and Metabolism | Year: 2015

Objective: To establish the frequency of the c.301-302 delAG mutation of the PROP1 gene in Romanian patients with multiple pituitary hormone deficiency (MPHD). Subjects and methods: Somatic assessment, hormonal test, bone age, magnetic resonance imaging of the pituitary gland, and molecular diagnosis were performed in 26 patients with MPHD (7 patients with familial form of MPHD and 19 patients with sporadic form of MPHD). Results: The c.301-302delAG mutation was detected in the homozygous state in 10 patients belonging to 5 unrelated families (7 patients with familial history of MPHD and 3 patients with sporadic form of MPHD). Those 10 patients presented variable pituitary hormone deficiency and pituitary morphology. Conclusions: The c.301-302delAG homozygous genotype had a high frequency of 38% (10/26), reaching 100% (7/7) in group with familial cases of MPHD and 16% (3/19) in group with sporadic forms of MPHD. © 2015 by De Gruyter.


PubMed | Montpellier University, Histologie Embryologie Cytogenetique, Nancy University Hospital Center, Service de Genetique Clinique and 18 more.
Type: Journal Article | Journal: Genetics in medicine : official journal of the American College of Medical Genetics | Year: 2016

Treacher Collins/Franceschetti syndrome (TCS; OMIM 154500) is a disorder of craniofacial development belonging to the heterogeneous group of mandibulofacial dysostoses. TCS is classically characterized by bilateral mandibular and malar hypoplasia, downward-slanting palpebral fissures, and microtia. To date, three genes have been identified in TCS:,TCOF1, POLR1D, and POLR1C.We report a clinical and extensive molecular study, including TCOF1, POLR1D, POLR1C, and EFTUD2 genes, in a series of 146 patients with TCS. Phenotype-genotype correlations were investigated for 19 clinical features, between TCOF1 and POLR1D, and the type of mutation or its localization in the TCOF1 gene.We identified 92/146 patients (63%) with a molecular anomaly within TCOF1, 9/146 (6%) within POLR1D, and none within POLR1C. Among the atypical negative patients (with intellectual disability and/or microcephaly), we identified four patients carrying a mutation in EFTUD2 and two patients with 5q32 deletion encompassing TCOF1 and CAMK2A in particular. Congenital cardiac defects occurred more frequently among patients with TCOF1 mutation (7/92, 8%) than reported in the literature.Even though TCOF1 and POLR1D were associated with extreme clinical variability, we found no phenotype-genotype correlation. In cases with a typical phenotype of TCS, 6/146 (4%) remained with an unidentified molecular defect.


PubMed | IUH, UF de Genetique moleculaire, Imagerie pediatrique, P&A Kyriakou Paed Hospital and 3 more.
Type: | Journal: BMC medical genetics | Year: 2015

Pelizaeus-Merzbacher disease (PMD) is an X-linked dysmyelinating disorder characterized by nystagmus, hypotonia, ataxia, progressive spasticity, and cognitive decline. PMD classically results from a duplication of a genomic segment encompassing the entire PLP1 gene. Since the PLP1 gene is located in Xq22, PMD affects mostly boys.Here we report the case of a girl with typical PMD. Copy number analysis of the PLP1 locus revealed a duplication of the entire gene and FISH analysis showed that the extra copy of the PLP1 gene was actually inserted in chromosome 1p36. This insertion of an additional copy of PLP1 in an autosome led to a functional duplication irrespective of the X-inactivation pattern. Subsequent overexpression of PLP1 was the cause of the PMD phenotype observed in this girl. Further sequencing of the breakpoint junction revealed a microhomology and thus suggested a replication based mechanism (such as FoSTeS or MMBIR).This case emphasizes the susceptibility of the PLP1 locus to complex rearrangement likely driven by the Xq22 local genomic architecture. In addition, careful consideration should be given to girls with classical PMD clinical features since they usually experience complex PLP1 genomic alteration with a distinct risk of inheritance.


Belkhribchia M.R.,Center Hospitalier Provincial Hassan | Collet C.,UF de Genetique Moleculaire | Laplanche J.-L.,UF de Genetique Moleculaire | Hassani R.,Cabinet ORL et Chirurgie Cervico faciale
European Journal of Medical Genetics | Year: 2014

Sclerosteosis (OMIM 269500) is a rare autosomal recessive condition characterized by increased bone density associated with syndactyly. It is linked to a genetic defect in the SOST gene coding for sclerostin. So far, seven different loss-of-function mutations in SOST have been reported in patients with sclerosteosis. Recently, two mutations in LRP4 gene underlying sclerosteosis were identified, reflecting the genetic heterogeneity of this disease.We report here a 30-years-old Moroccan man presented with typical clinical and radiological features of sclerosteosis who carries a novel homozygous mutation in the SOST gene, characterized as a nonsense mutation (c.79C>T; p.Gln27*) in exon 1 of the SOST gene. This is to our knowledge the first case of sclerosteosis reported from Morocco and North Africa. © 2014 Elsevier Masson SAS.


Caye A.,UF de Genetique Moleculaire | Beldjord K.,University Paris Diderot | Mass-Malo K.,UF de Genetique Moleculaire | Drunat S.,UF de Genetique Moleculaire | And 6 more authors.
Haematologica | Year: 2013

Deletion of the Ikaros (IKZF1) gene is an oncogenic lesion frequently associated with BCR-ABL1-positive acute lymphoblastic leukemias. It is also found in a fraction of BCR-ABL1-negative B-cell precursor acute lymphoblastic leukemias, and early studies showed it was associated with a higher risk of relapse. Therefore, screening tools are needed for evaluation in treatment protocols and possible inclusion in risk stratification. Besides monosomy 7 and large 7p abnormalities encompassing IKZF1, most IKZF1 alterations are short, intragenic deletions. Based on cohorts of patients, we mapped the microdeletion breakpoints and developed a breakpoint-specific fluorescent multiplex polymerase chain reaction that allows detection of recurrent intragenic deletions. This sensitive test could also detect IKZF1 sub-clonal deletions, whose prognostic significance should be evaluated. Moreover, we show that consensus breakpoint sequences can be used as clonal markers to monitor minimal residual disease. This paper could be useful for translational studies and in clinical management of BCP-ALL. (ClinicalTrials.gov Identifier: NCT00003728) © 2013 Ferrata Storti Foundation.


Fritez N.,Mohammed V University | Sobrier M.-L.,French Institute of Health and Medical Research | Sobrier M.-L.,Paris-Sorbonne University | Iraqi H.,Mohammed V University | And 14 more authors.
Clinical Endocrinology | Year: 2015

Background/Objectives Congenital hypopituitarism is a rare disease which, for most patients, has no identified molecular cause. We aimed to document the molecular basis of growth retardation in a Moroccan cohort. Design/Patients 80 index cases [54 with isolated growth hormone deficiency (IGHD), 26 with combined pituitary hormone deficiency (CPHD)] were screened for molecular defects in GH1 (including LCR-GH1), GHRHR, GHSR, GHRH, PROP1, POU1F1, HESX1, LHX3, LHX4 and SOX3. Results Five different deleterious mutations were identified in 14 patients from eight families. In the IGHD group, three genes were found to be involved: GH1, GHRHR and GHSR. In the CPHD group, PROP1 was the only mutated gene. In addition, two heterozygous variations whose deleterious effect remains to be demonstrated were identified (in GH1 and LHX4), and two polymorphisms (missense variations) were detected (in LHX3 and in GHSR). The prevalence of mutations in this Moroccan GHD cohort was 10% (8/80), 11·1% (6/54) in the IGHD group and 7·7% (2/26) in the CPHD group. Conclusion This is the first molecular screening of congenital GHD in a Moroccan population and, like other studies, mutations were preferentially identified in familial cases (75%); mutations in genes such as POU1F1, HESX1, SOX3, LHX3 and LHX4 are extremely rare. The p.R73C PROP1 mutation was the most frequent mutation in CPHD; this should be the first one to screen in this population. Our results should contribute to a better diagnosis and management of this heterogeneous disease condition. © 2014 John Wiley & Sons Ltd.


Masliah-Planchon J.,UF de Genetique Moleculaire | Darnige L.,Service dHematologie biologique | Bellucci S.,Service dHematologie biologique | Bellucci S.,University Paris Diderot
British Journal of Haematology | Year: 2013

Delta storage pool deficiency (δ-SPD) is a rare heterogeneous group of platelet disorders characterized by a reduction in the number or content of dense granules. δ-SPD causes a mild to moderate bleeding diathesis characterized mainly by mucocutaneous bleeding. Currently, no specific treatment is available and the therapeutic approach is based on prevention of excessive bleeding. However, during the last few years, important insights into the pathophysiology of δ-SPD have been achieved using mouse models and dense granule deficiency-associated congenital diseases, such as Hermansky-Pudlak syndrome and Chediak-Higashi syndrome. It thus appears that δ-SPD represents a genetically heterogeneous group of intracellular vesicle biogenesis and/or trafficking disorders. This review summarizes recent data regarding the molecular mechanisms together with clinical features of the different types of δ-SPD. Although the molecular basis of isolated inherited δ-SPD remains currently unknown, next-generation sequencing strategies should enable researchers to identify the causative genes. Identification of those genes should contribute to our understanding of the pathophysiology, represent useful tools for genetic diagnosis, and eventually lead to new specific therapeutic approaches. © 2012 Blackwell Publishing Ltd.


PubMed | UF de Genetique Moleculaire
Type: Journal Article | Journal: British journal of haematology | Year: 2012

Delta storage pool deficiency (-SPD) is a rare heterogeneous group of platelet disorders characterized by a reduction in the number or content of dense granules. -SPD causes a mild to moderate bleeding diathesis characterized mainly by mucocutaneous bleeding. Currently, no specific treatment is available and the therapeutic approach is based on prevention of excessive bleeding. However, during the last few years, important insights into the pathophysiology of -SPD have been achieved using mouse models and dense granule deficiency-associated congenital diseases, such as Hermansky-Pudlak syndrome and Chediak-Higashi syndrome. It thus appears that -SPD represents a genetically heterogeneous group of intracellular vesicle biogenesis and/or trafficking disorders. This review summarizes recent data regarding the molecular mechanisms together with clinical features of the different types of -SPD. Although the molecular basis of isolated inherited -SPD remains currently unknown, next-generation sequencing strategies should enable researchers to identify the causative genes. Identification of those genes should contribute to our understanding of the pathophysiology, represent useful tools for genetic diagnosis, and eventually lead to new specific therapeutic approaches.


Deletion of the Ikaros (IKZF1) gene is an oncogenic lesion frequently associated with BCR-ABL1-positive acute lymphoblastic leukemias. It is also found in a fraction of BCR-ABL1-negative B-cell precursor acute lymphoblastic leukemias, and early studies showed it was associated with a higher risk of relapse. Therefore, screening tools are needed for evaluation in treatment protocols and possible inclusion in risk stratification. Besides monosomy 7 and large 7p abnormalities encompassing IKZF1, most IKZF1 alterations are short, intragenic deletions. Based on cohorts of patients, we mapped the microdeletion breakpoints and developed a breakpoint-specific fluorescent multiplex polymerase chain reaction that allows detection of recurrent intragenic deletions. This sensitive test could also detect IKZF1 subclonal deletions, whose prognostic significance should be evaluated. Moreover, we show that consensus breakpoint sequences can be used as clonal markers to monitor minimal residual disease. This paper could be useful for translational studies and in clinical management of BCP-ALL.

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