Multiple, variable‐sized, minute marker chromosomes

Hoo, Joe J.; Lin, Chyi-Chyang; Optiz, John M.

doi:10.1002/ajmg.1320290215

Cited by 4 publications

(3 citation statements)

References 8 publications

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“…The finding of these cell lines could be due to reduced viability of these cells [CGte et al, 1981;Jones et al, 1981;Kistenmacher and Punnett, 1970;Kosztolanyi, 1987;Salamanca-G6mez et al, 19751 or because we cannot detect them. All the variable manifestations of this ring chromosome-monocentrics, interlocked rings, double rings, half-opened rings, variable-sized rings, and no ring at all (45 chromosomes)-can be explained as the consequence of a sister-chromatid exchange followed by an anaphase disturbance [Cdte et al, 1981;Hoo and Lin, 1988;Rocchi et al, 19841. Some investigators have drawn attention to the in vitro instability of some ring chromosomes over time [Cdte et al, 1981;Jones et al, 1981;Kistenmacher and Punnett, 1970;McDermott et al, 1977;Rocchi et al, 19841. These workers also suggested that the final phenotype will usually be related to one of 2 main effects:…”

Section: Discussionmentioning

confidence: 99%

Ring chromosome 6: Clinical and cytogenetic behaviour

et al. 1990

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Several investigators have reported in vitro instability of ring chromosomes. We have evaluated the clinical and cytogenetic course over 8 years in a patient with ring chromosome 6 and found stability in this ring chromosome. The different cell lines remained constant, and the phenotype showed little variation. This syndrome seems to be related to the deletion in the ring rather than to its instability.

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Section: Discussionmentioning

confidence: 99%

Ring chromosome 6: Clinical and cytogenetic behaviour

et al. 1990

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“…An excess of SRC is derived from acrocentric chromosomes [Plattner et al, 1993]. Sometimes the same chromosome ring can have different sizes and be monocentric or dicentric as a result of sister‐chromatid exchange and have a dosage effect [Hoo and Lin, 1988]. Rings with only heterochromatin are harmless, but in 60% of the cases with rings containing euchromatin an abnormal phenotype was found [Blennow and Tillberg, 1996].…”

Section: Resultsmentioning

confidence: 99%

“…Hoo and Lin [1988], noted that a maximum of five markers [Mascarello et al, 1987 and Tozzi et al, 1988] were possible but six markers in a cell were non‐viable. A single cell with six markers was noted in our patient 1.…”

Section: Resultsmentioning

confidence: 99%

SKY™ assessment of two karyotypes with 0–6 supernumerary marker/ring chromosomes and review of previously reported cases with two or more markers

Reddy

Wang

Groh

et al. 2003

American J of Med Genetics Pt A

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A 7-month-old boy with developmental delay and congenital abnormalities and a 58-year-old man with mental retardation, impaired speech, and dysmorphic features were referred for cytogenetic studies. The peripheral blood chromosome studies of Patient 1 had a de novo mosaic karyotype with 2-6 supernumerary marker chromosomes. Patient 2 had a mosaic karyotype with 1-5 supernumerary marker chromosomes and normal cells. All markers appeared to have a centromere by C-banding and also by fluorescence in situ hybridization (FISH) using all centromere probe for Patient 1. The majority of the markers appeared like rings. Except for one marker in Patient 1 and 2-3 markers in Patient 2 with discernible >5 Mb euchromatin, the rest of the markers were minute and some appeared to have barely discernible euchromatin in C-banding or FISH. Spectral karyotyping (SKY) was attempted to determine the origin of the marker chromosomes. Because some markers had barely any euchromatin, their classification was not clear cut and they were identified as derived from more than one chromosome. The SKY classification of the markers in Patient 1 was 1, 3, 5, 7, 11, 15, and 22 and in Patient 2 was 1, 5, 6, or 7. Patient 2 was lost to further follow-up studies. To confirm the recurring SKY classifications in Patient 1, centromere probes for chromosomes 1, 3, 5, 7, 11, 15, and 22 were used. The markers were negative for 1, 3, and 11 but positive for 7, 15, and 22 and probably 5. Since 5 centromere probe cross hybridizes with 1 and 19, the weak signal on the marker/s in successive hybridization did not give a definitive answer. Also, the 5 paint probe was not conclusive because of the minute size of the marker. In some metaphases, two markers were derived from 5 or 22. For clinical considerations, the marker derived from 7, although variable in size, appeared to consistently have euchromatin, followed by 15, while 22 and 5 markers were mostly centromeric heterochromatin. The elastin gene probe that maps to 7q11.23, SNRPN gene that maps to 15q11.2, and TUPLE gene that maps to 22q11.2 did not give a signal on the markers. As expected for a majority of ring chromosomes, the pan telomere probe did not hybridize to any of the markers. This highly unusual karyotype was confirmed in the buccal epithelium using a mix of centromere 7 and 15 probes and the combination 14/22 probe. The ratio of additional FISH signals in the buccal mucosal cells was comparable to the ratios observed in the peripheral blood. In this study, we have attempted to consolidate the data on >/=2 marker cases to understand the analysis constraints, the range of clinical abnormalities, and the mechanisms involved. The literature was surveyed for multiple markers cases. A majority of the reported cases had two markers, either derived from the same chromosome or from two different chromosomes or two cell lines with different markers derived from the same chromosome. Cases with three or more markers were rare. The nature and extent of euchromatin content of the multiple markers appears to...

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Efficient identification of marker chromosomes in 27 patients by stepwise hybridization with alpha-satellite DNA probes

et al. 1993

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Using a procedure involving stepwise hybridization of alpha-satellite DNA probes at various conditions of stringency, 33 marker chromosomes from 27 patients were identified. The markers were ascertained prenatally in fetal amniotic fluid and chorionic villi samples or postnatally in blood from liveborn children. The marker chromosomes first were characterized by cytogenetic techniques and later identified by fluorescence in situ hybridization. There were 14 bisatellited markers, 3 metacentric nonsatellited marker chromosomes, 2 nonsupernumerary sex-chromosomal rings, and 9 patients carrying markers that appeared to be small rings. Multiple stringency conditions were used for the identification of 14 supernumerary ringlike chromosomes detected in 8 patients. Ring-like markers were initially screened at low stringency and grouped into alpha-satellite families. Subsequent higher stringency hybridization led to marker identification. Ringlike chromosomes originated from chromosomes 1, 2, 8, 12, 13 or 21, 14 or 22, 15, 18, and X. Multiple ringlike markers ascertained in a single patient were determined to originate from different chromosomes.

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Multiple, variable‐sized, minute marker chromosomes

Cited by 4 publications

References 8 publications

Ring chromosome 6: Clinical and cytogenetic behaviour

Ring chromosome 6: Clinical and cytogenetic behaviour

SKY™ assessment of two karyotypes with 0–6 supernumerary marker/ring chromosomes and review of previously reported cases with two or more markers

Efficient identification of marker chromosomes in 27 patients by stepwise hybridization with alpha-satellite DNA probes

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