Laboratoire Of Biochimie Et Genetique

Créteil, France

Laboratoire Of Biochimie Et Genetique

Créteil, France
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Pingault V.,Laboratoire Of Biochimie Et Genetique | Pingault V.,French Institute of Health and Medical Research | Pingault V.,University Paris Est Creteil | Pierre-Louis L.,Maison de la Femme de la Mere et de lEnfant MFME | And 9 more authors.
American Journal of Medical Genetics, Part A | Year: 2014

Waardenburg syndrome (WS) is characterized by an association of pigmentation abnormalities and sensorineural hearing loss. Four types, defined on clinical grounds, have been delineated, but this phenotypic classification correlates imperfectly with known molecular anomalies. SOX10 mutations have been found in patients with type II and type IV WS (i.e., with Hirschsprung disease), more complex syndromes, and partial forms of the disease. The phenotype induced by SOX10 mutations is highly variable and, except for the neurological forms of the disease, no genotype-phenotype correlation has been characterized to date. There is no mutation hotspot in SOX10 and most cases are sporadic, making it particularly difficult to correlate the phenotypic and genetic variability. This study reports on three independent families with SOX10 mutations predicted to result in the same missense mutation at the protein level (p.Met112Ile), offering a rare opportunity to improve our understanding of the mechanisms underlying phenotypic variability. The pigmentation defects of these patients are very similar, and the neurological symptoms showed a somewhat similar evolution over time, indicating a potential partial genotype-phenotype correlation. However, variability in gastrointestinal symptoms suggests that other genetic factors contribute to the expression of these phenotypes. No correlation between the rs2435357 polymorphism of RET and the expression of Hirschsprung disease was found. In addition, one of the patients has esophageal achalasia, which has rarely been described in WS. © 2014 Wiley Periodicals, Inc.

Helias V.,National Institute of Blood Transfusion INTS | Saison C.,National Institute of Blood Transfusion INTS | Peyrard T.,National Institute of Blood Transfusion INTS | Peyrard T.,National Reference Center for Blood Groups | And 5 more authors.
Human Mutation | Year: 2013

KLF1 encodes an erythroid transcription factor, whose essential function in erythropoiesis has been demonstrated by extensive studies in mouse models. The first reported mutations in human KLF1 were found in individuals with a rare and asymptomatic blood type called In(Lu). Here, we show that KLF1 haploinsufficiency is responsible for the In(Lu) blood type, after redefining this peculiar blood type using flow cytometry to quantify the levels of BCAM and CD44 on red blood cells. We found 10 (seven novel) heterozygous KLF1 mutations responsible for the In(Lu) blood type. Although most were obligate loss-of-function mutations due to the truncation of the DNA-binding domain of KLF1, three were missense mutations that were located in its DNA-binding domain and impaired the transactivation capacity of KLF1 in vitro. We further showed that the levels of the hemoglobin variants HbF and HbA2 were increased in the In(Lu) blood type, albeit differently. The levels of the membrane glycoproteins BCAM and CD44 were also differently reduced on In(Lu) red blood cells. This biochemical and genetic analysis of the In(Lu) blood type tackles the phenotypic outcome of haploinsufficiency for a transcription factor. © 2012 Wiley Periodicals, Inc.

Pingault V.,French Institute of Health and Medical Research | Pingault V.,University Paris Est Creteil | Pingault V.,Laboratoire Of Biochimie Et Genetique | Bodereau V.,Laboratoire Of Biochimie Et Genetique | And 25 more authors.
American Journal of Human Genetics | Year: 2013

Transcription factor SOX10 plays a role in the maintenance of progenitor cell multipotency, lineage specification, and cell differentiation and is a major actor in the development of the neural crest. It has been implicated in Waardenburg syndrome (WS), a rare disorder characterized by the association between pigmentation abnormalities and deafness, but SOX10 mutations cause a variable phenotype that spreads over the initial limits of the syndrome definition. On the basis of recent findings of olfactory-bulb agenesis in WS individuals, we suspected SOX10 was also involved in Kallmann syndrome (KS). KS is defined by the association between anosmia and hypogonadotropic hypogonadism due to incomplete migration of neuroendocrine gonadotropin-releasing hormone (GnRH) cells along the olfactory, vomeronasal, and terminal nerves. Mutations in any of the nine genes identified to date account for only 30% of the KS cases. KS can be either isolated or associated with a variety of other symptoms, including deafness. This study reports SOX10 loss-of-function mutations in approximately one-third of KS individuals with deafness, indicating a substantial involvement in this clinical condition. Study of SOX10-null mutant mice revealed a developmental role of SOX10 in a subpopulation of glial cells called olfactory ensheathing cells. These mice indeed showed an almost complete absence of these cells along the olfactory nerve pathway, as well as defasciculation and misrouting of the nerve fibers, impaired migration of GnRH cells, and disorganization of the olfactory nerve layer of the olfactory bulbs. © 2013 The American Society of Human Genetics.

Rakotoson M.G.,University Paris Est Creteil | Di Liberto G.,University Paris Est Creteil | Audureau E.,University Paris Est Creteil | Habibi A.,University Paris Est Creteil | And 7 more authors.
Orphanet Journal of Rare Diseases | Year: 2015

Background: Dense red blood cells (DRBCs) are associated with chronic clinical manifestations of sickle-cell-disease (SCD). Hydroxyurea (HU) decreases the percent (%) DRBCs, thereby improving its therapeutic benefits, especially the prevention of SCD clinical complications, but parameters influencing %DRBCs remain unknown. The purpose of this study was to determine predictive biological parameters of %DRBC decline under HU. Methods: Factors affecting the %DRBC decrease in SCD patients HU-treated for ≥6 months were analyzed. Biological parameters and the %DRBCs were determined before starting HU and after ≥6 months of HU intake. Bivariate analyses evaluated the impact of each biological parameter variation on %DRBC changes under treatment. Multivariate analyses assessed the correlations between the decreased %DRBCs and biological parameters. Results: The %DRBCs declined by 40.95% after ≥6 months on HU. That decrease was associated with less hemolysis, however in several analyses on this group of patients we did not find a statistically significant correlation between decrease in %DRBCs and increase in HbF. Initial %DRBC values were the most relevant parameter to predict %DRBC decline. Conclusion: Our results strengthen the known HU efficacy in SCD management statistically independently of the classical HbF biological response. Decreasing %DRBCs is essential to limiting chronic SCD symptoms related to DRBCs and predictive factors might help prevent those manifestations. The results of this study provide new perspectives on indication for HU use, i.e., to prevent SCD-induced organ damage. © 2015 Rakotoson et al.; licensee BioMed Central.

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