Clinical Heterogeneity in 16 Patients
with inv dup 15 Chromosome:
Cytogenetic and Molecular Studies,
Search for an Imprinting Effect

Mignon, C.; Malzac, Perrine; Moncla, Anne; Depétris, D.; Roëckel, Nathalie; Croquette, Marie‐Françoise; Mattéi, Marie Geneviève

doi:10.1159/000472176

Cited by 71 publications

(77 citation statements)

References 35 publications

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“…2,4,10,22,23 Further analyses of our data show that within the acrocentric SMCs, 20% of the SMC(15) and SMC (22) were mosaic compared with 31% for SMC (14) and 50% for SMC(13/21) respectively. Previous reports on SMC(15) have shown that on average B85% of SMC(15)s present as nonmosaics 13,24,28 and the majority of SMC (22) reported are also nonmosaics. 25,26 The fact that the majority of SMC(15) are nonmosaics suggests a meiotic origin of these markers and this is supported by the observations that all de novo SMC(15)s characterized molecularly have been shown to be maternal in origin, 11,24,27 -29 and in a proportion of those containing additional copies of the PWACR, molecular studies show that they are divided equally between being inter-and intrachromosomal in origin.…”

Section: Mosaicism and The Chromosomal Origins Of Smcsmentioning

confidence: 89%

Supernumerary marker chromosomes in man: parental origin, mosaicism and maternal age revisited

et al. 2004

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The details of all cytogenetic abnormalities diagnosed in the Wessex Regional Genetics Laboratory (WRGL) since 1967 to the present day have been recorded in the Salisbury Treasury of Interesting Chromosomes (STOIC). From this resource, we identified 137 patients with constitutional autosomal supernumerary marker chromosomes (SMC) ascertained in four principal groups: (i) 37% with abnormal phenotypes; (ii) 7% couples with reproductive difficulties; (iii) 47% antenatal diagnoses and (iv) 9% miscellaneous. Overall, 81 (59%) SMCs were mosaics and 56 (41%) nonmosaics. Of the 109 cases with known parental origins, 70% were de novo, 19% maternally and 11% paternally inherited. The chromosomal origins of 112/137 (82%) of the SMCs have been determined by fluorescence in situ hybridization (FISH). In all, 36/112 (32%) were derived from nonacrocentric autosomes, and 76/112 (68%) from the acrocentric autosomes 13/21, 14, 15 and 22. Of these acrocentric SMCs, 39 (51%) were derived from chromosome 15, so that SMC(15) constituted 39/112 (35%) of all SMCs with known chromosomal origins. The frequencies with which mosaicism was observed varied considerably according to the chromosomal origin of the SMCs and accounted for 8/39 (20%) SMC(15), 13/37 (35%) SMCs from other acrocentrics and 25/36 (69%) of nonacrocentric SMCs. The data were analysed for parental age effects, and only de novo SMC(15)s were found to be associated with a significantly increased maternal age.

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Section: Mosaicism and The Chromosomal Origins Of Smcsmentioning

confidence: 89%

Supernumerary marker chromosomes in man: parental origin, mosaicism and maternal age revisited

et al. 2004

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“…4,11 -13,29 -31 They are also involved in small inv dup 15 chromosomes that are associated with a normal phenotype. 7,9,32 Three distal BPs have been described (Figure 1). BP3 is the most common distal BP involved in PWS/AS deletions, interstitial duplications, and inv dup (15).…”

Section: Discussionmentioning

confidence: 99%

Recurrent rearrangements in the proximal 15q11–q14 region: a new breakpoint cluster specific to unbalanced translocations

et al. 2007

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Unbalanced translocations, that involve the proximal chromosome 15 long arm and the telomeric region of a partner chromosome, result in a karyotype of 45 chromosomes with monosomy of the proximal 15q imprinted region. Here, we present our analysis of eight such unbalanced translocations that, depending on the parental origin of the rearranged chromosome, were associated with either Prader -Willi or Angelman syndrome. First, using FISH with specific BAC clones, we characterized the chromosome 15 breakpoint of each translocation and demonstrate that four of them are clustered in a small 460 kb interval located in the proximal 15q14 band. Second, analyzing the sequence of this region, we demonstrate the proximity of a low-copy repeat 15 (LCR15)-duplicon element that is known to facilitate recombination events at meiosis and to promote rearrangements. The presence, in this region, of both a cluster of translocation breakpoints and a LCR15-duplicon element defines a new breakpoint cluster (BP6), which, to our knowledge, is the most distal breakpoint cluster described in proximal 15q. Third, we demonstrate that the breakpoints for other rearrangements including large inv dup (15) chromosomes do not map to BP6, suggesting that it is specific to translocations. Finally, the translocation breakpoints located within BP6 result in very large proximal 15q deletions providing new informative genotype -phenotype correlations.

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“…The structure and formation of the supernumerary idic(15) chromosomes are similar to the CES chromosomes. Depending on their size, the breakpoints of the idic(15) chromosomes correspond to both the proximal and distal breakpoints of deletions seen in PWS and AS (Donlon et al, 1986;Knoll et al, 1990;Cheng et al, 1994;Christian et al, 1995;Mignon et al, 1996;Huang et al, 1997). Therefore, the mechanisms by which these rearrangements occur on chromosomes 15 and 22 may be similar.…”

Section: Discussionmentioning

confidence: 99%

Cat eye syndrome chromosome breakpoint clustering: identification of two intervals also associated with 22q11 deletion syndrome breakpoints

McTaggart¹,

Budarf

Driscoll

et al. 1998

Cytogenet Genome Res

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The supernumerary cat eye syndrome (CES) chromosome is dicentric, containing two copies of 22pter→q11.2. We have found that the duplication breakpoints are clustered in two intervals. The more proximal, most common interval is the 450–650 kb region between D22S427 and D22S36, which corresponds to the proximal deletion breakpoint interval found in the 22q11 deletion syndrome (DiGeorge/velocardiofacial syndrome). The more distal duplication breakpoint interval falls between CRKL and D22S112, which overlaps with the common distal deletion interval of the 22q11 deletion syndrome. We have therefore classified CES chromosomes into two types based on the location of the two breakpoints required to generate them. The smaller type I CES chromosomes are symmetrical, with both breakpoints located within the proximal interval. The larger type II CES chromosomes are either asymmetrical, with one breakpoint located in each of the two intervals, or symmetrical, with both breakpoints located in the distal interval. The co-localization of the breakpoints of these different syndromes, plus the presence of low-copy repeats adjacent to each interval, suggests the existence of several specific regions of chromosomal instability in 22q11.2 which are involved in the production of both deletions and duplications. Since the phenotype associated with the larger duplication does not appear to be more severe than that of the smaller duplication, determination of the type of CES chromosome does not currently have prognostic value.

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Clinical Heterogeneity in 16 Patients with inv dup 15 Chromosome: Cytogenetic and Molecular Studies, Search for an Imprinting Effect

Cited by 71 publications

References 35 publications

Supernumerary marker chromosomes in man: parental origin, mosaicism and maternal age revisited

Supernumerary marker chromosomes in man: parental origin, mosaicism and maternal age revisited

Recurrent rearrangements in the proximal 15q11–q14 region: a new breakpoint cluster specific to unbalanced translocations

Cat eye syndrome chromosome breakpoint clustering: identification of two intervals also associated with 22q11 deletion syndrome breakpoints

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