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Dijon, France

Faivre L.,University of Burgundy | Van Kien P.K.,Montpellier University Hospital Center | Callier P.,Cytogenetique | Ruiz-Pallares N.,Montpellier University Hospital Center | And 17 more authors.
European Journal of Medical Genetics

Interstitial deletions involving the 15q21.1 band are very rare. Only 4 of these cases have been studied using molecular cytogenetic techniques in order to confirm the deletion of the whole FBN1 gene. The presence of clinical features of the Marfan syndrome (MFS) spectrum associated with mental retardation has been described in only 2/4 patients. Here we report on a 16-year-old female referred for suspicion of MFS (positive thumb and wrist sign, scoliosis, joint hyperlaxity, high-arched palate with dental crowding, dysmorphism, mitral insufficiency with dystrophic valve, striae). She had therefore 3 minor criteria according to the Ghent nosology. She also had speech disabilities but could follow normal school training. Direct sequencing of the FBN1, TGFBR1 and TGFBR2 genes was negative. MLPA revealed a genomic deletion of the whole FBN1 gene, confirmed by loss of heterozygosity of maternal alleles for several microsatellite markers surrounding the FBN1 gene. The deletion was confirmed by FISH using a FBN1 probe and was not found in the parents. Array-CGH permitted to define a 2.97 Mb deletion, which was the smallest 15q microdeletion including FBN1. Contrary to the other published observations, our proband does not exhibit mental retardation, but neuropsychological evaluations revealed an attention deficit as well as a deficit in information-processing speed. Haploinsufficiency of FBN1 is likely to contribute to the presence of MFS features. However, attenuated features could be explained because disturbances of TGF-β signalling associated with FBN1 mutations do not exert full phenotypic effect through simple haploinsufficiency. Phenotypic variability in other patients with interstitial deletions including 15q21.1 band may reflect differences in deletion size and/or cys/trans modifying factors. © 2010 Elsevier Masson SAS. Source

Callier P.,Laboratoire Of Cytogenetique | Andrieux J.,Cytogenetique | Delobel B.,Groupe Hospitalier Of Linstitut Catholique Lillois | David A.,Nantes University Hospital Center | And 14 more authors.
European Journal of Human Genetics

Speech sound disorders are heterogeneous conditions, and sporadic and familial cases have been described. However, monogenic inheritance explains only a small proportion of such disorders, in particular in cases with childhood apraxia of speech (CAS). Deletions of <5Mb involving the 12p13.33 locus is one of the least commonly deleted subtelomeric regions. Only four patients have been reported with such a deletion diagnosed with fluorescence in situ hybridisation telomere analysis or array CGH. To further delineate this rare microdeletional syndrome, a French collaboration together with a search in the Decipher database allowed us to gather nine new patients with a 12p13.33 subtelomeric or interstitial rearrangement identified by array CGH. Speech delay was found in all patients, which could be defined as CAS when patients had been evaluated by a speech therapist (5/9 patients). Intellectual deficiency was found in 5/9 patients only, and often associated with psychiatric manifestations of various severity. Two such deletions were inherited from an apparently healthy parent, but reevaluation revealed abnormal speech production at least in childhood, suggesting variable expressivity. The ELKS/ERC1 gene, which encodes for a synaptic factor, is found in the smallest region of overlap. These results reinforce the hypothesis that deletions of the 12p13.33 locus may be responsible for variable phenotypes including CAS associated with neurobehavioural troubles and that the presence of CAS justifies a genetic work-up. © 2013 Macmillan Publishers Limited. All rights reserved. Source

Benko S.,French Institute of Health and Medical Research | Benko S.,University of Paris Descartes | Gordon C.T.,French Institute of Health and Medical Research | Gordon C.T.,University of Paris Descartes | And 20 more authors.
Journal of Medical Genetics

Background: The early gonad is bipotential and can differentiate into either a testis or an ovary. In XY embryos, the SRY gene triggers testicular differentiation and subsequent male development via its action on a single gene, SOX9. The supporting cell lineage of the bipotential gonad will differentiate as testicular Sertoli cells if SOX9 is expressed and conversely will differentiate as ovarian granulosa cells when SOX9 expression is switched off. Results: Through copy number variation mapping this study identified duplications upstream of the SOX9 gene in three families with an isolated 46, XX disorder of sex development (DSD) and an overlapping deletion in one family with two probands with an isolated 46, XY DSD. The region of overlap between these genomic alterations, and previously reported deletions and duplications at the SOX9 locus associated with syndromic and isolated cases of 46, XX and 46, XY DSD, reveal a minimal noncoding 78 kb sex determining region located in a gene desert 517-595 kb upstream of the SOX9 promoter. Conclusions: These data indicate that a non-coding regulatory region critical for gonadal SOX9 expression and subsequent normal sex development is located far upstream of the SOX9 promoter. Its copy number variations are the genetic basis of isolated 46, XX and 46, XY DSDs of variable severity (ranging from mild to complete sex reversal). It is proposed that this region contains a gonad specific SOX9 transcriptional enhancer(s), the gain or loss of which results in genomic imbalance sufficient to activate or inactivate SOX9 gonadal expression in a tissue specific manner, switch sex determination, and result in isolated DSD. Source

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