A neocentromere derived from a supernumerary marker deleted from the long arm of chromosome 6

Qin, Nana; Bartley, James; Wang, J.-C.; Warburton, Peter E.

doi:10.1159/000109633

Cited by 5 publications

(3 citation statements)

References 22 publications

(10 reference statements)

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“…Three cases with 6q21q23 duplications were described only at the cytogenetic level and associated with developmental delay, congenital hearts defects, depressed nasal bridge and epicanthal folds [ 15 , 16 ] and two cases of 6q21q22.1 in a mother and her daughter showed similar phenotypes (cognitive difficulties, obesity, essential tremor) and café-au-lait spots in the daughter [ 17 ]. Regarding other regions of 6q chromosome, trisomy 6qter has also been associated with mental retardation and obesity starting from childhood [ 18 , 19 ], but cases of neocentric sSMC (6q) phenotypes show no similarity to ours [ 12 , 20 , 21 ]. Our patient’s complex sSMC involves chromosome 10 too and it is, to the best of our knowledge, the first report of a complex sSMC involving chromosome 10 and characterized by array-CGH.…”

Section: Discussionmentioning

confidence: 92%

6q16.3q23.3 duplication associated with Prader-Willi-like syndrome

et al. 2015

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BackgroundPrader-Willi syndrome (PWS) is characterized by hypotonia, delayed neuropsychomotor development, overeating, obesity and mental deficiency. This phenotype is encountered in other conditions, defining Prader-Willi-like syndrome (PWLS).Case presentationWe report a 14-year-old boy with a complex small supernumerary marker chromosome (sSMC) associated with PWLS. The propositus presents clinical features commonly found in patients with PWLS, including growth hormone deficit. Banding karyotype analysis and fluorescence in situ hybridization (FISH) revealed a marker derived from chromosome 6 and a neocentromere as suspected, but array-CGH enabled us to characterize this marker as a der(10)t(6;10)(6qter → 6q23.3::10p11.1 → 10p11.21)dn. As far as we know, this is the first diagnosed case of PWLS associated with a complex sSMC, involving a 30.9 Mb gain in the 6q16.3q23.3 region and a 3.5 Mb gain in the 10p11.21p11.1 region. Several genes have been mapped to the 6q region including the TCBA1 gene, which is associated with developmental delay and recurrent infections, the ENPP1 gene, associated with insulin resistance and susceptibility to obesity and the BMIQ3 gene, associated with body mass index (BMI). No OMIM gene was found in the smallest 10p11.21p11.1 region.ConclusionsWe suggest that the duplicated chromosome segment 6q16.3q23.3 may be responsible for the phenotype of our case and may also be a candidate locus of PWLS.

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Section: Discussionmentioning

confidence: 92%

6q16.3q23.3 duplication associated with Prader-Willi-like syndrome

et al. 2015

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“…[]; e Nasiri et al []; f Maraschio et al []; g Baldwin et al []; h Andersen et al []; i Pfeiffer et al []; j Krauss et al []; k Stavropoulou et al []; l Mannens et al []; m Wandall et al []; n Liehr et al []; o Vlckova et al []; p Chuang et al []; q Donlon et al []; r Knegt et al []; s Friedman and Harrod. []; t Quack et al []; u Toutain et al []; v Reynolds et al []; w Manvelyan et al []; x Qin et al []; y Burnside et al []; z Slater et al []; aa Cui et al []; bb Lasan Trcic et al [].…”

Section: Discussionmentioning

confidence: 99%

A Marfan syndrome‐like phenotype caused by a neocentromeric supernumerary ring chromosome 15

Quinonez

Gelehrter

Uhlmann

2016

American J of Med Genetics Pt A

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Small supernumerary marker chromosomes (sSMC) are abnormal chromosomes that cannot be characterized by standard banding cytogenetic techniques. A minority of sSMC contain a neocentromere, which is an ectopic centromere lacking the characteristic alpha-satellite DNA. The phenotypic manifestations of sSMC and neocentromeric sSMC are variable and range from severe intellectual disability and multiple congenital anomalies to a normal phenotype. Here we report a patient with a diagnosis of Marfan syndrome and infertility found to have an abnormal karyotype consisting of a chromosome 15 deletion and a ring-type sSMC likely stabilized by a neocentromere derived via a mechanism initially described by Barbara McClintock in 1938. Analysis of the sSMC identified that it contained the deleted chromosome 15 material and also one copy of FBN1, the gene responsible for Marfan syndrome. We propose that the patient's diagnosis arose from disruption of the FBN1 allele on the sSMC. To date, a total of 29 patients have been reported with an sSMC derived from a chromosomal deletion. We review these cases with a specific focus on the resultant phenotypes and note significant difference between this class of sSMC and other types of sSMC. Through this review we also identified a patient with a clinical diagnosis of neurofibromatosis type 1 who lacked a family history of the condition but was found to have a chromosome 17-derived sSMC that likely contained NF1 and caused the patient's disorder. We also review the genetic counseling implications and recommendations for a patient or family harboring an sSMC. © 2016 Wiley Periodicals, Inc.

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“…Further evidence for epigenetic effects in centromere specification came from the analysis of neo-centromeric chromosomes [28][29][30][31][32][33][34][35][36][37][38][39]. These chromosomes are the products of complex re-arrangements in which an interstitial euchromatic chromosome region acquires the function of centromeric DNA and nucleates the formation of a kinetochore.…”

Section: Introductionmentioning

confidence: 99%

Centromeres: Old tales and new tools

2008

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The centromere is a specialised region of the eukaryotic chromosome that directs the equal segregation of sister chromatids into two daughter cells during mitosis. In mitosis, the kinetochores mediate (1) microtubule capture and chromosome alignment at a metaphase plate; (2) the correction of improper microtubule attachments; (3) the maintenance of an active checkpoint until bi-orientation is achieved by the whole complement of chromosomes; (4) the establishment of tension within the centromere which, in turn, contributes to silencing of the spindle checkpoint and triggers the onset of anaphase.In this review, we will analyse how centromeres are organised with respect to chromatin types and arrangements.

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A neocentromere derived from a supernumerary marker deleted from the long arm of chromosome 6

Cited by 5 publications

References 22 publications

6q16.3q23.3 duplication associated with Prader-Willi-like syndrome

6q16.3q23.3 duplication associated with Prader-Willi-like syndrome

A Marfan syndrome‐like phenotype caused by a neocentromeric supernumerary ring chromosome 15

Centromeres: Old tales and new tools

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