Sub-band deletion of 7q36.3 in a patient with ring chromosome 7: Association with holoprosencephaly

Sawyer, Jeffrey R.; Lukacs, Janet L.; Hassed, Susan J.; Arnold, Georgianne L.; Mitchell, Heather F.; Muenke, Maximilian

doi:10.1002/(sici)1096-8628(19961016)65:2<113::aid-ajmg6>3.0.co;2-t

Cited by 15 publications

(17 citation statements)

References 20 publications

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“…One of the most significant features present in almost all the cases with a large ring chromosome (group 2) is the presence of skin lesions. Out of the 14 cases with large ring chromosomes, 13 showed skin lesions such as vascular lesions (hemangiomas) café‐au‐lait spots and pigmented nevi (1–12, 14). Such strong association between the presence of a large ring chromosome 7 and skin lesions has led some investigators to propose a possible link between ring chromosome and malignant melanoma (17).…”

Section: Discussionmentioning

confidence: 99%

De novo supernumerary ring chromosome 7: first report of a non‐mosaic patient and review of the literature

Velagaleti

Jalal

Kukolich³

et al. 2002

Clinical Genetics

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The present authors report the case of a 12-year-old-boy with a de novo, non-mosaic supernumerary ring chromosome 7 associated with significant developmental delay and speech difficulty. A review of the literature identified a total of 18 cases with ring chromosomes 7 who can be classified into two groups: (1) patients with a cell line that has 47 chromosomes with a small supernumerary ring chromosome 7 resulting in partial trisomy; and (2) individuals had a cell line with a large ring chromosome replacing one of the normal chromosomes 7 resulting in partial monosomy. A comparison of clinical features in the two groups of patients showed several common features such as growth and mental retardation, and facial dysmorphism, including, ear and eye anomalies. However, patients with partial trisomy have speech difficulty as a distinguishing feature, while patients with partial monosomy have skin lesions as a cardinal feature. All the published cases of ring chromosome 7, irrespective whether they are supernumerary or normal modal number, are mosaics except for one. The present subject is the first case of a de novo, non-mosaic supernumerary ring chromosome 7.

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Section: Discussionmentioning

confidence: 99%

De novo supernumerary ring chromosome 7: first report of a non‐mosaic patient and review of the literature

Velagaleti

Jalal

Kukolich³

et al. 2002

Clinical Genetics

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“…Patient 33, who has the brain and facial findings of HPE (Sawyer et al 1996), was found to be deleted for BAC 6787 and cosmid 241a1. In contrast, patient 34 who did not have HPE retained the FISH signal for BAC 6787 consistent with our original hypothesis of a critical region for HPE3 lying in the vicinity of the T1 breakpoint.…”

Section: Ring Chromosomementioning

confidence: 99%

Cytogenetic rearrangements involving the loss of the Sonic Hedgehog gene at 7q36 cause holoprosencephaly

et al. 1997

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Holoprosencephaly (HPE) is a genetically heterogeneous disorder that affects the midline development of the forebrain and midface in humans. As a step toward identifying one of the HPE genes, we have set out to refine the HPE3 critical region on human chromosome 7q36 by analyzing 34 cell lines from families with cytogenetic abnormalities involving 7q, 24 of which are associated with HPE. Genomic clones surrounding the DNA marker D7S104, which has previously been shown to be in the HPE3 critical region, have been examined by fluorescent in situ hybridization and microsatellite analysis of our panel of patient cell lines. We report the analysis of a cluster of four translocation breakpoints within a 300-kb region of 7q36 that serves to define the minimal critical region for HPE3 and that has directed the search for candidate genes. The human Sonic Hedgehog (hSHH) gene maps to this region and has been shown to be HPE3 on the basis of mutations within the coding region of the gene. We present evidence that cytogenetic deletions and/or rearrangements of this region of chromosome 7q containing Sonic Hedgehog, and translocations that may suppress Sonic Hedgehog gene expression through a position effect are common mechanisms leading to HPE.

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“…As a consequence of the deletion of 7q terminal genes, holoprosencephaly (HPE) and features of Currarino syndrome (OMIM #176450) have been reported in patients with r(7) [Tsukamoto et al, ; Sawyer et al, ; Roessler et al, ; Rodríguez et al, ]. Of the 7q36 deleted genes, in particular SHH plays a critical role in ventral CNS development.…”

Section: Discussionmentioning

confidence: 99%

“…The phenotypes associated with r(7) are extremely variable, however, common features include pre‐ and postnatal growth retardation, microcephaly, intellectual disability, and variable dermatologic findings. In six reported patients, subtelomeric analyses have been carried out and five showed cryptic deletions [Sawyer et al, ; Roessler et al, ; Rodríguez et al, ; Mehraein et al, ; Tsai et al, ], nevertheless, the breakpoint analyses have not been carried out in any of these reports. Here we report the clinical, cytogenetic and molecular profile of a male child with a non‐supernumerary r(7), who presents dynamic mosaicism in different tissues confirmed by single nucleotide polymorphism (SNP) array analysis.…”

Section: Introductionmentioning

confidence: 99%

Cytogenomic and phenotypic analysis in low‐level monosomy 7 mosaicism with non‐supernumerary ring chromosome 7

Salas-Labadía

Cervantes-Barragán

Cruz-Alcívar

et al. 2014

American J of Med Genetics Pt A

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We present the literature review of ring chromosome 7 and clinical, cytogenetic and fine molecular mapping of the first postnatal report of a male child with a non-supernumerary ring chromosome 7, r(7). The patient had dysmorphic features, developmental delay, dermatologic lesions with variable pigmentation, hypogenitalism, lumbar dextroscoliosis, cerebellar and ophthalmological abnormalities, and melanocytic congenital nevi. Cytogenetic analysis of peripheral blood and the nevus sample showed the presence of three different cell lines r(7), monosomy 7, and duplicated r(7) (idic r(7)), while findings on fibroblasts from both light and dark skin showed only mosaicism with r(7) and monosomy 7 cell lines in various proportions. FISH assay of the ring chromosome showed subtelomeric loss in both chromosome arms in all tissues studied. Analysis by genome-wide single-nucleotide polymorphism array showed a 0.8 Mb deletion in 7p22.3 (involving eight genes) and a 7.5 Mb deletion in 7q36 (involving 29 genes including some involved in genital and central nervous system development). The combination of results from our karyotypic and array analyses enabled us to establish an accurate genotype-phenotype relationship.

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Sub-band deletion of 7q36.3 in a patient with ring chromosome 7: Association with holoprosencephaly

Cited by 15 publications

References 20 publications

De novo supernumerary ring chromosome 7: first report of a non‐mosaic patient and review of the literature

De novo supernumerary ring chromosome 7: first report of a non‐mosaic patient and review of the literature

Cytogenetic rearrangements involving the loss of the Sonic Hedgehog gene at 7q36 cause holoprosencephaly

Cytogenomic and phenotypic analysis in low‐level monosomy 7 mosaicism with non‐supernumerary ring chromosome 7

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