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M Prieur

Publications and source records attributed to M Prieur.

At least 19 recordsLinked to original sources
PubMed2006

Major feeding difficulties in the first reported case of interstitial 20q11.22-q12 microdeletion and molecular cytogenetic characterization.

We report on a 4-year-old female presenting with intrauterine growth retardation, facial dysmorphic features, major feeding difficulties with severe diarrhea and vomiting, mental retardation with abnormal behavior and hypertonia. Feeding difficulties were the most invalidating features with absent oral intake requiring persistent enteral feeding. Standard cytogenetic studies were normal, but high-resolution chromosome analyses revealed a small de novo interstitial deletion of the long arm of chromosome 20, 46,XX,del(20)(q11.21q12). The deletion was confirmed using metaphase comparative genomic hybridization (CGH) and multicolor high resolution banding (mBAND). The deletion breakpoints were characterized using FISH analyses with YACs, PACs, and BACs clones located in the deleted and adjacent regions. A 6.6-Mb deleted region between markers D20S815 (20q11.22) and D20S435 (20q12) could be delineated. None of the nine previously reported cases with interstitial 20q deletion found in the literature involve the same breakpoints. This report further emphasizes the indication of high-resolution chromosome analyses in children with syndromic mental retardation. The description of additional cases would be useful in order to better characterize the phenotype of patients with proximal interstitial 20q deletion.

Abnormalities, Multiple↗
PubMed2006

Array-based comparative genomic hybridisation identifies high frequency of cryptic chromosomal rearrangements in patients with syndromic autism spectrum disorders.

BACKGROUND: Autism spectrum disorders (ASD) refer to a broader group of neurobiological conditions, pervasive developmental disorders. They are characterised by a symptomatic triad associated with qualitative changes in social interactions, defect in communication abilities, and repetitive and stereotyped interests and activities. ASD is prevalent in 1 to 3 per 1000 people. Despite several arguments for a strong genetic contribution, the molecular basis of a most cases remains unexplained. About 5% of patients with autism have a chromosome abnormality visible with cytogenetic methods. The most frequent are 15q11-q13 duplication, 2q37 and 22q13.3 deletions. Many other chromosomal imbalances have been described. However, most of them remain undetectable using routine karyotype analysis, thus impeding diagnosis and genetic counselling. METHODS AND RESULTS: 29 patients presenting with syndromic ASD were investigated using a DNA microarray constructed from large insert clones spaced at approximately 1 Mb intervals across the genome. Eight clinically relevant rearrangements were identified in 8 (27.5%) patients: six deletions and two duplications. Altered segments ranged in size from 1.4 to 16 Mb (2-19 clones). No recurrent abnormality was identified. CONCLUSION: These results clearly show that array comparative genomic hybridisation should be considered to be an essential aspect of the genetic analysis of patients with syndromic ASD. Moreover, besides their importance for diagnosis and genetic counselling, they may allow the delineation of new contiguous gene syndromes associated with ASD. Finally, the detailed molecular analysis of the rearranged regions may pave the way for the identification of new ASD genes.

Adolescent↗
PubMed2005

Molecular cytogenetic analysis of five 2q37 deletions: refining the brachydactyly candidate region.

Deletions of the 2q37 region are associated with a recognizable pattern of MCA/MR so-called the AHO-like syndrome. Brachydactyly is a variable but characteristic feature of this clinical entity. Here we report on five cases of cytogenetically visible de novo deletions of this 2q37 chromosome region. Using FISH, we characterized at the molecular level the breakpoints of these deletions using a set of 15 BACs, PACs and YACs. In four patients, terminal deletions of variable size ranged between 6.2 and 10 Mb. The fifth patient had an interstitial deletion with an AHO-like phenotype including brachydactyly. These findings when compared to previous observations allowed us to narrow down the brachydactyly critical region between BACs RP11-585E12 and RP11-351E10. It contains HDAC4 and STK25 candidate genes loci.

Adult↗
PubMed2004

Genome-wide screening using automated fluorescent genotyping to detect cryptic cytogenetic abnormalities in children with idiopathic syndromic mental retardation.

Mental retardation (MR) is the most common developmental disability, affecting approximately 2% of the population. The causes of MR are diverse and poorly understood, but chromosomal rearrangements account for 4-28% of cases, and duplications/deletions smaller than 5 Mb are known to cause syndromic MR. We have previously developed a strategy based on automated fluorescent microsatellite genotyping to test for telomere integrity. This strategy detected about 10% of cryptic subtelomeric rearrangements in patients with idiopathic syndromic MR. Because telomere screening is a first step toward the goal of analyzing the entire genome for chromosomal rearrangements in MR, we have extended our strategy to 400 markers evenly distributed along the chromosomes to detect interstitial anomalies. Among 97 individuals tested, three anomalies were found: two deletions (one in three siblings) and one parental disomy. These results emphasize the value of a genome-wide microsatellite scan for the detection of interstitial aberrations and demonstrate that automated genotyping is a sensitive method that not only detects small interstitial rearrangements and their parental origin but also provides a unique opportunity to detect uniparental disomies. This study will hopefully contribute to the delineation of new contiguous gene syndromes and the identification of new imprinted regions.

Child↗
PubMed2003

Spectrum of NSD1 mutations in Sotos and Weaver syndromes.

Sotos syndrome is an overgrowth syndrome characterised by pre- and postnatal overgrowth, macrocephaly, advanced bone age, and typical facial features. Weaver syndrome is a closely related condition characterised by a distinctive craniofacial appearance, advanced carpal maturation, widened distal long bones, and camptodactyly. Haploinsufficiency of the NSD1 gene has recently been reported as the major cause of Sotos syndrome while point mutations accounted for a minority of cases. We looked for NSD1 deletions or mutations in 39 patients with childhood overgrowth. The series included typical Sotos patients (23/39), Sotos-like patients (lacking one major criteria, 10/39), and Weaver patients (6/39). We identified NSD1 deletions (6/33) and intragenic mutations (16/33) in Sotos syndrome patients. We also identified NSD1 intragenic mutations in 3/6 Weaver patients. We conclude therefore that NSD1 mutations account for most cases of Sotos syndrome and a significant number of Weaver syndrome cases in our series. Interestingly, mental retardation was consistently more severe in patients with NSD1 deletions. Macrocephaly and facial gestalt but not overgrowth and advanced bone age were consistently observed in Sotos syndrome patients. We suggest therefore considering macrocephaly and facial gestalt as mandatory criteria for the diagnosis of Sotos syndrome and overgrowth and advanced bone age as minor criteria.

Abnormalities, Multiple↗
PubMed2002

Automated fluorescent genotyping detects 10% of cryptic subtelomeric rearrangements in idiopathic syndromic mental retardation.

Recent studies have shown that cryptic unbalanced subtelomeric rearrangements contribute to a significant proportion of idiopathic syndromic mental retardation cases. Using a fluorescent genotyping based strategy, we found a 10% rate of cryptic subtelomeric rearrangements in a large series of 150 probands with severe idiopathic syndromic mental retardation and normal RHG-GTG banded karyotype. Fourteen children were found to carry deletions or duplications of one or more chromosome telomeres and two children had uniparental disomy. This study clearly shows that fluorescent genotyping is a sensitive and cost effective method that not only detects cryptic subtelomeric rearrangements but also provides a unique opportunity to detect uniparental disomies. We suggest giving consideration to systematic examination of subtelomeric regions in the diagnostic work up of patients with unexplained syndromic mental retardation.

Child↗
PubMed2001

Chromosome 10p11.2-p12.2 duplication: report of a patient and review of the literature.

We report on a young male with mental retardation, slightly upslanting palpebral fissures, strabismus, high-arched palate, retrognathia, and flat feet. Cytogenetic analysis in addition to fluorescent in situ hybridization (FISH) and comparative genomic hybridization (CGH) showed the presence of a chromosome 10p11.2-->p12.2 duplication. Karyotypes of the parents were normal. Comparison of the clinical findings observed in the present patient with those observed in other reported cases with duplication 10p suggest that the presence of high arched/cleft palate and retrognathia may be related to the 10p11.2-->p12.2 duplication. Also, no critical region for the trisomy 10p syndrome has been delimited.

Abnormalities, Multiple↗
PubMed2001

Large-scale deletions and SMADIP1 truncating mutations in syndromic Hirschsprung disease with involvement of midline structures.

Hirschsprung disease (HSCR) is a common malformation of neural-crest-derived enteric neurons that is frequently associated with other congenital abnormalities. The SMADIP1 gene recently has been recognized as disease causing in some patients with 2q22 chromosomal rearrangement, resulting in syndromic HSCR with mental retardation, with microcephaly, and with facial dysmorphism. We screened 19 patients with HSCR and mental retardation and eventually identified large-scale SMADIP1 deletions or truncating mutations in 8 of 19 patients. These results allow further delineation of the spectrum of malformations ascribed to SMADIP1 haploinsufficiency, which includes frequent features such as hypospadias and agenesis of the corpus callosum. Thus, SMADIP1, which encodes a transcriptional corepressor of Smad target genes, may play a role not only in the patterning of neural-crest-derived cells and of CNS but also in the development of midline structures in humans.

Abnormalities, Multiple↗
PubMed2001

Partial maternal heterodisomy of chromosome 17q25 in a case of severe mental retardation.

We report a segmental maternal uniparental heterodisomy of chromosome 17 (mat UPD17) in a 3-year-old boy presenting with hyperactivity, major instability, mental retardation and facial dysmorphism. Since conventional and high resolution karyotypes were normal, this patient was tested for cryptic telomeric rearrangements by using the recently developed fluorescent genotyping-based technology. The mat UPD17 segment extended for a small 11-cM region of the distal chromosome 17q. Trisomy 17 in circulating lymphocytes and skin fibroblasts was excluded. Our finding emphasizes the potential use of fluorescent genotyping to detect uniparental disomies and suggests that chromosome 17q25 should contain one or several imprinted genes of particular importance for brain development.

Child, Preschool↗
PubMed2001

Comparative genomic hybridisation in mentally retarded patients with dysmorphic features and a normal karyotype.

Segmental aneusomy for small chromosomal regions has been shown to be a common cause of mental retardation and multiple congenital anomalies. A screening method for such chromosome aberrations that are not detected using standard cytogenetic techniques is needed. Recent studies have focused on detection of subtle terminal chromosome aberrations using subtelomeric probes. This approach however excludes significant regions of the genome where submicroscopic rearrangements are also liable to occur. The aim of the present study was to evaluate the efficiency of comparative genomic hybridisation (CGH) for screening of submicroscopic chromosomal rearrangements. CGH was performed in a cohort of 17 patients (14 families) with mental retardation, dysmorphic features and a normal karyotype. Five subtle unbalanced rearrangements were identified in 7 patients. Subsequent FISH studies confirmed these results. Although no interstitial submicroscopic rearrangement was detected in this small series, the study emphasises the value of CGH as a screening approach to detect subtle chromosome rearrangements in mentally retarded patients with dysmorphic features and a normal karyotype.

Cytogenetic Analysis↗
PubMed2001

A novel automated strategy for screening cryptic telomeric rearrangements in children with idiopathic mental retardation.

Cryptic unbalanced subtelomeric rearrangements are known to cause a significant proportion of idiopathic mental retardation in childhood. Because of the limited sensitivity of routine analyses, the cytogenetic detection of such rearrangements requires molecular techniques, namely FISH and comparative genomic hybridisation (CGH). An alternative approach consists in using genetic markers to detect segmental aneusomy. Here, we describe a new strategy based upon automated fluorescent genotyping to search for non mendelian segregation of telomeric microsatellites. A total of 29 individuals belonging to 24 unrelated families were screened and three abnormal patterns of segregation were detected (two rearrangements and one parental disomy). This study gives strong support to the view that cryptic telomeric rearrangements significantly contribute to idiopathic mental retardation and demonstrates that fluorescent genotyping is a very sensitive and cost-effective method to detect deletions, duplications and uniparental disomies.

Child↗
PubMed2000

Chromosome 7q22-q31 duplication: report of a new case and review.

We report on a girl with psychomotor retardation, growth retardation, microcephaly, frontal bossing, large ears, small nose, high arched and narrow palate, short neck, and generalized hirsutism. Cytogenetic analysis in addition to fluorescent in situ hybridization (FISH) and comparative genomic hybridization (CGH) showed the presence of a chromosome 7q22-->q31.3 duplication. Comparison with other reported cases shows some resemblance but insufficient to enable us to establish a definite syndrome with specific clinical manifestations. The importance in better analyzing further cases by new molecular cytogenetics techniques is raised.

Child↗
PubMed2000

Apparent Sotos syndrome (cerebral gigantism) in a child with trisomy 20p11.2-p12.1 mosaicism.

We report on a child with apparent Sotos syndrome (cerebral gigantism) and partial duplication of the short arm of chromosome 20 mosaicism. Trisomy 20p11.2-p12.1 was diagnosed using cytogenetic and FISH studies. The somatostatin receptor 4 (SSTR4) gene is included in the duplicated segment. This suggests that a dosage effect of this gene might be related to some of the clinical findings observed in our patient. The present observation emphasizes the importance of chromosome analysis in patients with well-delineated but sporadic conditions.

Adult↗