Characterization of a de novo Supernumerary Neocentric Ring Chromosome Derived from Chromosome 7

Louvrier, Camille; Egéa, Grégory; Labalme, Audrey; Portes, Vincent Des; Gazzo, Sophie; Callet‐Bauchu, Evelyne; Till, Marianne; Sanlaville, Damien; Edery, Patrick; Schluth-Bolard, Caroline

doi:10.1159/000442265

Cited by 3 publications

(1 citation statement)

References 23 publications

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“…Recently, Kumar et al reported a child with dysmorphic features and developmental delay, who presented a complex chromosome rearrangement involving chromosome 7 and resulting of a class II/McClintock mechanism [6]. Louvrier et al [7] reported a mosaic neocentric ring involving the region 7q22.1q31.1, in a child with a severe global retardation and dysmorphic features. In this case, the aSMC characterization, using arrayCGH, and the clinical description are very detailed establishing a clear genotype-phenotype correlation.…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of a rare analphoid supernumerary marker chromosome derived from 7q35 → qter: a case report

et al. 2016

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BackgroundAnalphoid supernumerary marker chromosomes (aSMC) constitute one of the smallest groups of SMC, and are characterized by a centromeric constriction but no detectable alpha-satellite DNA. These marker chromosomes cannot be properly identified by conventional banding techniques alone, and molecular cytogenetic methods are necessary for a detailed characterization. Analphoid SMC derived from chromosome 7 are extremely rare, with only five cases reported so far.Case presentationIn this work we report an aSMC involving the terminal long arm of chromosome 7 in a 10-year-old boy with multiple dysmorphic features and severe development delay. Cytogenetic analysis revealed a mosaic karyotype with the presence of an extra SMC, de novo, in 20% of lymphocytes and 73% of fibroblast cells. Next, we performed FISH analysis with multiple DNA probes and cCGH analysis. This identified the origin of the SMC as an analphoid marker resulting of invdup rearrangement of 7q35-qter region.Affimetrix CytoScan HD array analysis redefined the aSMC as a 15.42 Mb gain at 7q35-q36.3 (minimum tetraplicated region-chr7: 143,594,973-159,119,707; GRCh37/hg19) of maternal origin that encloses 67 OMIM genes, 16 of which associated to disease. Uniparental disomy of chromosome 7 (UPD 7) has been excluded.ConclusionsWe report the first patient with an aSMC(7) derived from the terminal 7q region who has been molecularly and clinically full characterized. The use of SNParray in the characterization of SMC reveals to be a powerful tool, giving information not only about copy number variation but also about loss-of-heterozygosity and parental origin. We conclude that an integrated genome-wide copy number variation analysis, if possible associated to FISH and gene expression studies, could facilitate in the future the difficult task of establishing accurate genotype-phenotype correlations and help to improve genetic counselling.

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Section: Introductionmentioning

confidence: 99%

Molecular characterization of a rare analphoid supernumerary marker chromosome derived from 7q35 → qter: a case report

et al. 2016

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A Case of Trisomy 13 Mosaicism Presenting with a Severe Aortic Root Dilatation and Marfanoid Habitus due to an Unpredictable Cytogenetic Mechanism

Monin

Reynaud

Hanna

et al. 2020

Cytogenet Genome Res

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In this report, we present a new case of mosaic trisomy 13 with prolonged survival, firstly detected by array-CGH analysis which was carried out because of moderate intellectual disability with postaxial hexadactyly, dermatologic features, ventricular septal defect, bicuspid aortic valve, and aortic dystrophy in a 19-year-old male patient. In a subset of 15% of the cells, the patient carried a derivative chromosome 10 generated by a nonreciprocal (10;13) translocation inherited from his healthy mother who carried the translocation in a balanced and homogeneous state. FISH analyses showed interstitial telomeric sequences at the breakpoints. To our knowledge, this is the second report of a patient with trisomy 13 mosaicism displaying a severe aortic root dilatation. We also discuss the mechanisms which could explain the mosaic state, the most likely one being related to the instability of the interstitial telomere.

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A marker chromosome in post-transplant bone marrow

2016

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Detection of small supernumerary marker chromosomes in karyotype analysis represents a diagnostic challenge. While such markers are usually detected during cytogenetic studies of constitutional chromosome abnormalities, they have also been found in specimens submitted from patients with acquired malignancies. We report here the detection of a marker chromosome in a bone marrow specimen from a patient who received a bone marrow transplantation. We discuss the importance of proper characterization and interpretation of marker chromosomes in clinical practice.

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Characterization of a de novo Supernumerary Neocentric Ring Chromosome Derived from Chromosome 7

Cited by 3 publications

References 23 publications

Molecular characterization of a rare analphoid supernumerary marker chromosome derived from 7q35 → qter: a case report

Molecular characterization of a rare analphoid supernumerary marker chromosome derived from 7q35 → qter: a case report

A Case of Trisomy 13 Mosaicism Presenting with a Severe Aortic Root Dilatation and Marfanoid Habitus due to an Unpredictable Cytogenetic Mechanism

A marker chromosome in post-transplant bone marrow

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