An apparently acentric marker chromosome originating from 9p with a functional centromere without detectable alpha and beta satellite sequences

Vance, Gail H.; Curtis, Christine A.; Heerema, Nyla A.; Schwartz, Stuart; Palmer, Catherine G.

doi:10.1002/(sici)1096-8628(19970905)71:4<436::aid-ajmg13>3.0.co;2-h

Cited by 19 publications

(7 citation statements)

References 29 publications

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“…The centromere of the mammalian chromosome is generally considered critical for normal chromosome segregation. Acentric stably inherited chromosomes, however, have been reported [Voullaire et al, 1993; Ohashi et al, 1994; Blennow et al, 1994; Maraschio et al, 1996; Depinet et al, 1997; Vance et al, 1997, Tyler‐Smith et al, 1999]. Although the centromere is absent in some cases, a primary constriction is present.…”

Section: Introductionmentioning

confidence: 99%

Boy with bilateral retinoblastoma due to an unusual ring chromosome 13 with activation of a latent centromere

et al. 2001

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We present a patient with bilateral retinoblastoma and developmental delay who has an abnormal male karyotype containing 47 chromosomes, including an acentric derivative chromosome 13. We postulate that the derivative 13 occurred after a break at 13q14, with the proximal portion of the chromosome forming a ring and the distal portion undergoing duplication. Thus, this patient is trisomic for 13q14-->qter. The derivative chromosome with duplicated distal portion (13q14-->qter) lacked the 13 centromere and was negative for chromosome 13 alpha-satellite DNA by low stringency FISH. Nevertheless, this chromosome is stably transmitted in lymphocytes and fibroblasts. A single primary constriction was observed at band 13q21, consistent with activation of a latent centromere (neocentromere) at this band. The neocentromere on der(13) was positive for multiple centromeric proteins, suggesting that it acts as the functional centromere. By FISH, the Rb gene was present on the normal 13, the proximally derived ring chromosome, but not on the derivative chromosome. Although there was no evidence for disruption of the Rb gene, this chromosome rearrangement most likely results in abnormal expression of the Rb gene product.

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Section: Introductionmentioning

confidence: 99%

Boy with bilateral retinoblastoma due to an unusual ring chromosome 13 with activation of a latent centromere

et al. 2001

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“…Marker chromosomes have now been identified that lack alphoid sequences yet have some degree of mitotic stability and possess a constriction similar to the primary constriction seen at the centromere [du Sart et al, 1997; Barry et al, 1999; for review, see Choo, 1997]. In addition, these marker chromosomes bind centromeric proteins in a manner consistent with a functional centromere [Ohashi et al, 1994; Vance et al, 1997; Depinet et al, 1997; du Sart et al, 1997; Tyler‐Smith et al, 1999]. These marker chromosomes provide evidence that the presence of α‐satellite sequences by itself is not a prerequisite for the formation of a functional centromere.…”

Section: Introductionmentioning

confidence: 99%

Analphoid 3qter markers

et al. 2000

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Two cases of marker chromosomes derived from a non-centromeric location were studied to determine the characteristics of these markers with respect to the presence of functional centromeres and whether an associated phenotype could be described. The markers were characterized by fluorescence in situ hybridization and centromeric protein studies. Assessments were done to identify clinical features. Case 1 is a girl referred at age 1.5 years with swirly areas of hyperpigmentation, bilateral preauricular pits, hypotonia, developmental delay, and seizures. Case 2 is a male first evaluated as a newborn and then later during the first year of life. He had streaky hypopigmentation, right preauricular pit, accessory nipples, postaxial polydactyly, asymmetric cerebral ventricles, duplicated right kidney, a right pulmonary artery stenosis, and seizures. Mosaicism for an extra marker from the 3qter region was present in both cases. Both markers had a constriction near one end and were C-band negative. Centromeric protein studies indicated absence of CENP-B, presence of CENP-C (data for case 1 only), and presence of CENP-E. Marker chromosomes were thus identified with a chromosomal origin far from their usual centromeric region and yet appeared to have functional centromeres. These two cases did not permit a specific clinical phenotype to be ascribed to the presence of tetrasomy for 3q26.2 approximately 3q27.2-->3qter.

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“…Nonsatellited and C‐band negative marker chromosomes should be tested for absence of alphoid sequences by use of an all centromere α‐satellite probe to assess for neocentromeres. Chromosome painting probes can provide confirmation of the origin of the marker, if the karyotype gives a preliminary indication [Abeliovich et al, 1996; Vance et al, 1997]. Spectral karyotyping [Huang et al, 1998] and subtelomeric probes (present study) can be used for other, unidentifiable acentric markers.…”

Section: Discussionmentioning

confidence: 95%

Mosaic tetrasomy 8q: Inverted duplication of 8q23.3qter in an analphoid marker

et al. 2000

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We observed an analphoid marker chromosome stable through cell division in a 16-year-old girl with developmental delay, short stature, limb contractures, and ovaries containing multiple cysts. She also developed myasthenia gravis at 15 years. The marker chromosome, present in 75% of metaphases (and in 90% of transformed lymphoblastoid cells), was C-band negative, and had no pan alpha-satellite sequences detectable by fluorescence in situ hybridization (FISH). The 8q origin of the marker was determined by use of subtelomeric probes and was confirmed by chromosome 8 painting probes. The marker was shown to be an inversion duplication of 8q when subtelomeric, telomeric, and c-myc FISH probes hybridized to both ends of the marker. The karyotype was 47,XX,+inv dup(8)(qter--> q23.3::q23.3-->[neocen]-->qter), resulting in tetrasomy for 8q23.3qter. The parents had normal karyotypes. Centromeric proteins CENP-C and CENP-E were present, but alpha associated centromere protein CENP-B was absent at a position defining a neocentromere.

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An apparently acentric marker chromosome originating from 9p with a functional centromere without detectable alpha and beta satellite sequences

Cited by 19 publications

References 29 publications

Boy with bilateral retinoblastoma due to an unusual ring chromosome 13 with activation of a latent centromere

Boy with bilateral retinoblastoma due to an unusual ring chromosome 13 with activation of a latent centromere

Analphoid 3qter markers

Mosaic tetrasomy 8q: Inverted duplication of 8q23.3qter in an analphoid marker

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