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Rittinger O, Krabichler B, Kronberger G, Kotzot D. Clinical, cytogenetic, and molecular findings in a patient with a 46,XX,del(18)(q22)/46,XX,idic(18)(q22) karyotype. Eur J Med Genet 2015; 58:603-7. [PMID: 26417856 DOI: 10.1016/j.ejmg.2015.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/16/2015] [Accepted: 09/23/2015] [Indexed: 11/30/2022]
Abstract
Pseudoisodicentric or asymmetrical dicentric chromosomes 18 are rare findings in clinical cytogenetics. So far, only 8 patients with breakpoints in 18q have been reported and in none of them breakpoints were narrowed down to the molecular level. Here, we describe a 17 months old girl with a perimembranous ventricular septal defect, cleft palate, and minor dysmorphism including hypertelorism, flat nose, frontal bossing and low set ears as well as mosaicism for a cell line with a pseudoisodicentric chromosome 18q and a second cell line with a terminal deletion of 11 Mb in 18q22.2→qter. SNP-array investigation revealed a symmetric breakpoint in 18q22.2 and most likely postzygotic formation from the maternal chromosome 18. Clinical findings in all patients reported so far as well as in the patient presented here were in part overlapping with the clinical phenotypes of trisomy 18 and partial monosomy 18q.
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Affiliation(s)
- Olaf Rittinger
- Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Birgit Krabichler
- Division of Human Genetics, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Gabriela Kronberger
- Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Dieter Kotzot
- Division of Human Genetics, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
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Maguld NA, Hablblan R. Isodicentric chromosome 18 in an abnormal infant using chromosome specific DNA probe. Clin Genet 2008. [DOI: 10.1111/j.1399-0004.1992.tb03670.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Daniel A, St Heaps L, Sylvester D, Diaz S, Peters G. Two mosaic terminal inverted duplications arising post-zygotically: Evidence for possible formation of neo-telomeres. CELL & CHROMOSOME 2008; 7:1. [PMID: 18331649 PMCID: PMC2292745 DOI: 10.1186/1475-9268-7-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 03/10/2008] [Indexed: 01/30/2023]
Abstract
Objective To elucidate the structure of terminal inverted duplications and to investigate potential mechanisms of formation in two cases where there was mosaicism with cells of apparently normal karyotype. Results A karyotype [46,XY,inv dup(4)(p16.3p15.1)/46,XY] performed on blood lymphocytes from a patient referred for developmental delay (case 1) demonstrated a normal karyotype in 60% of cells with a terminal inverted duplication 4p in the remainder. In case 2, referred for multiple fetal anomalies on an ultrasound scan, 33% of amniocyte colonies were karyotypically normal, with a terminal inv dup 10p in the remainder [46,XX,inv dup(10)(p15.3p11)/46,XX]. Duplicated FISH signals for GATA3 and NEBL loci (in case 2), and for the Wolf-Hirschhorn locus (case 1) confirmed the inverted structure of both duplications. In the GTL banded normal cells from both cases, there was a cryptic deletion detected by FISH of one copy of the subtelomere 4p (case 1, probe GS-36P21), and subtelomere 10p (case 2, probe GS-306F7). At pter on both inv dup chromosomes there was no FISH signal present for the specific subtelomere probe. However, a positive pantelomeric probe signal was detected at 4 pter and 10 pter in both the cryptically-deleted chromosomes and the inv dup chromosomes in the respective cell lines of both cases. Conclusion An inv dup structure was evident for both cases on GTL bands, and confirmed by the various FISH studies. The presence of telomere (TTAGGG repeat) sequences at pter on the inv dup chromosomes (where more proximal chromosome specific subtelomeric probes were negative) was indicated by the pantelomeric probe signals in both cases. We conclude the most likely mechanism of origin in both cases was by sub-telomeric breakage in the zygote at pter, and delayed repair/rearrangement until after one or more subsequent mitotic divisions. In these divisions, at least one breakage-fusion-bridge cycle occurred, to produce inverted duplications. It is proposed then that two differently "repaired" daughter cells proliferated in parallel. In one daughter cell line (with an overtly normal karyotype) there was deletion of the subtelomere and presumed repair through capping by a neo-telomere (i.e. "healing", as initially proposed by McClintock). This occurred in both cases presented. In the other daughter cell of each case, it is proposed that chromosome stabilization was achieved (after replication) by sister chromatid reunion to form a dicentric, which broke at a subsequent anaphase, to form an inverted duplication (with loss of the reciprocal product, and the other daughter cell line). One inv dup was repaired without an interstitial specific subtelomere (case 1) and one was repaired with a duplicated specific interstitial subtelomere (case 2). After repair TTAGGG repeats were detected by FISH at each respective new pter.
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Affiliation(s)
- Art Daniel
- Department of Cytogenetics, Western Sydney Genetics Program, The Children's Hospital at Westmead, NSW 2145, Australia.
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Turan S, Saka N, Guney I, Bereket A. A patient with hypopituitarism and isochromosome 18q mosaicism. HORMONE RESEARCH 2005; 64:261-5. [PMID: 16272819 DOI: 10.1159/000089424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Accepted: 08/18/2005] [Indexed: 11/19/2022]
Abstract
AIMS Patients with isochromosome 18 [i(18q)] have features of both trisomy 18 and deletion of 18p [del(18p)] syndromes. Although, hypopituitarism has been reported in patients with del(18p) syndrome, it has not been described in patients with i(18q) syndrome previously. We describe a case with i(18q)/del(18p) mosaicism associated with a novel finding of hypopituitarism. METHODS Clinical characteristics of the patient have been discussed in the light of the literature. RESULTS The patient had dysmorphic findings that are predominantly seen in del(18p) syndrome such as low nasal bridge, wide mouth, large ears, high forehead, hypopigmentation, upturned nostrils and hypopituitarism (TSH, ACTH, and GH deficiencies, and pituitary hypoplasia on magnetic resonance imaging). In addition, she also had upturning of upper lip and seizures, which are features of trisomy 18 syndrome. CONCLUSIONS In agreement with the previous clinical reports, this case further supports the presence of a factor, which is involved in pituitary development and/or function, on the short arm of chromosome 18.
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Affiliation(s)
- Serap Turan
- Department of Paediatric Endocrinology, Marmara University Faculty of Medicine, Istanbul, Turkey
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Bugge M, Brandt CA, Petersen MB. DNA studies of mono- and pseudodicentric isochromosomes 18q. Am J Med Genet A 2005; 127A:230-3. [PMID: 15150771 DOI: 10.1002/ajmg.a.30026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The description of isochromosomes 18 has so far mainly been by cytogenetic studies and based on identical banding pattern of the two arms. However, only molecular techniques are capable to distinguish an isochromosome from a translocation, whole arm or reciprocal, between two chromosomes 18. We have used 23 PCR-based DNA polymorphisms to determine the parental origin and mechanisms of formation in four patients with isochromosomes 18q and to demonstrate that they were consistent with true isochromosomes. Three of the probands were liveborn children with clinical features characteristic of Edwards syndrome, one proband was a fetus diagnosed at prenatal diagnosis. In one case the isochromosome was monocentric with two identical q arms of maternal origin, formed by misdivision of the centromere and loss of p arm material. Another monocentric case had 47 chromosomes with isochromosomes i(18p) and i(18q) formed by maternal postzygotic centromeric misdivision and segregation of both isochromosomes, or by meiosis II centromeric misdivision and nondisjunction (without recombination in meiosis I). In two cases, the isochromosomes were dicentric with genetically identical arms composed of a part of the short and the whole long arm of chromosome 18 of paternal origin. The formation of the fused chromosomes can be explained by postzygotic exchange of sister chromatids on the short arm of chromosome 18, followed by breakage and U-shape reunion of sister chromatids.
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Affiliation(s)
- Merete Bugge
- Wilhelm Johannsen Centre for Functional Genome Research, Department of Medical Genetics, University of Copenhagen, Denmark.
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Meins M, Böhm D, Großmann A, Herting E, Fleckenstein B, Fauth C, Speicher MR, Schindler R, Zoll B, Bartels I, Burfeind P. First non-mosaic case of isopseudodicentric chromosome 18 (psu idic(18)(pter → q22.1::q22.1 → pter) Is associated with multiple congenital anomalies reminiscent of trisomy 18 and 18q− syndrome. Am J Med Genet A 2003; 127A:58-64. [PMID: 15103719 DOI: 10.1002/ajmg.a.20644] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Isopseudodicentric chromosome 18 is very rare and results in a combination of partial trisomy and partial monosomy of chromosome 18. We report here a hypotrophic newborn with a lateral cleft lip and palate and multiple craniofacial dysmorphisms, a combined heart defect, unilateral hypoplasia of the kidney, bilateral aplasia of thumbs, and generalized contractures. Cytogenetic analysis revealed an isopseudodicentric chromosome 18 with breakpoint in 18q (46,XX,psu idic(18)(pter --> q22.1::q22.1 --> pter)). The isopseudodicentric chromosome 18 was observed in 100% of blood lymphocytes and umbilical cord fibroblasts, thus indicating a non-mosaic finding of the isopseudodicentric chromosome in the child. An elongated derivative chromosome 18 had also been found prenatally in amniotic cells. In contrast, a terminal deletion (18q-) was detected in placental cell cultures. The breakpoint was mapped to a 0.9 Mb region on 18q22.1 (located 64.8-65.7 Mb from the telomere of the p-arm) by a novel quantitative PCR approach with SYBR green detection. The results indicate an identical breakpoint of the isopseudodicentric chromosome 18 in the child and the 18q- chromosome in the placenta. To our knowledge this is the first report that a fetus carrying an isopseudodicentric chromosome 18 with breakpoint in 18q (46,XX,psu idic(18)(pter --> q22.1::q22.1 --> pter)) in non-mosaic form can be viable, but is associated with severe congenital malformations of the child.
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Affiliation(s)
- M Meins
- Institute of Human Genetics, University of Göttingen, Germany
| | - D Böhm
- Institute of Human Genetics, University of Göttingen, Germany
| | - A Großmann
- Department of Pediatrics, University of Göttingen, Germany
| | - E Herting
- Department of Pediatrics, University of Göttingen, Germany
| | - B Fleckenstein
- Department of Obstetrics and Gynecology, University of Göttingen, Germany
| | - C Fauth
- Institute of Human Genetics, Technical University München and GSF, National Research Center for Environment and Health, Neuherberg, Germany
| | - M R Speicher
- Institute of Human Genetics, Technical University München and GSF, National Research Center for Environment and Health, Neuherberg, Germany
| | - R Schindler
- Institute of Human Genetics, University of Göttingen, Germany
| | - B Zoll
- Institute of Human Genetics, University of Göttingen, Germany
| | - I Bartels
- Institute of Human Genetics, University of Göttingen, Germany
| | - Peter Burfeind
- Institute of Human Genetics, University of Göttingen, Germany
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Chen CP, Chern SR, Lee CC, Town DD. Isochromosome 18q in a fetus with congenital megacystis, intra-uterine growth retardation and cloacal dysgenesis sequence. Prenat Diagn 1998. [DOI: 10.1002/(sici)1097-0223(1998100)18:10<1068::aid-pd384>3.0.co;2-a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ausems MG, Bhola SL, Post-Blok CA, Hennekam RC, de France HF. 18q- and 18q+ mosaicism in a mentally retarded boy. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 53:296-9. [PMID: 7856666 DOI: 10.1002/ajmg.1320530317] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A mentally retarded boy was found to have an unusual chromosomal mosaicism [46,XY, del(18) (q22)/46,XY,iso psu dic(18)(q23)]. The clinical manifestations are compatible with the 18q- syndrome. The chromosome alteration was defined by high resolution banding and fluorescence in situ hybridization (FISH). A mechanism to explain the origin of the two cell lines is presented and discussed.
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Affiliation(s)
- M G Ausems
- Clinical Genetics Center Utrecht, The Netherlands
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van Essen AJ, Schoots CJ, van Lingen RA, Mourits MJ, Tuerlings JH, Leegte B. Isochromosome 18q in a girl with holoprosencephaly, DiGeorge anomaly, and streak ovaries. AMERICAN JOURNAL OF MEDICAL GENETICS 1993; 47:85-8. [PMID: 8368259 DOI: 10.1002/ajmg.1320470117] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We report on the clinical and pathologic findings in a girl with isochromosome 18q (46, XX,i(18q)) who had combined manifestations of monosomy 18p and trisomy 18q. Major congenital anomalies included premaxillary agenesis, alobar holoprosenphaly, double outlet right ventricle, DiGeorge anomaly and streak ovaries. The clinical spectrum in i(18q) is very broad.
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Affiliation(s)
- A J van Essen
- Department of Medical Genetics, University of Groningen, The Netherlands
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Fujiwara M, Kamasaki H, Morita Y, Kamada M. A mosaic case of isodicentric chromosome 18. ACTA PAEDIATRICA JAPONICA : OVERSEAS EDITION 1992; 34:534-8. [PMID: 1442026 DOI: 10.1111/j.1442-200x.1992.tb01002.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A case of mosaicism of isodicentric chromosome 18 is reported. Dicentric chromosome 18 occurs rarely and only five cases of isodicentric chromosome 18 have been documented. A high resolution banding method revealed that the karyotype of the patient was mos 46,XX/46,XX idic(18)(pter-->q21.3::q21.3-->pter), and the ratio of normal and abnormal clones was 1:1. The clinical manifestations, resembling those of trisomy 18 syndrome, were affected by both partial trisomy 18pter-->q21.3 and partial monosomy 18q21.3-->qter.
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Affiliation(s)
- M Fujiwara
- Department of Pediatrics, Hakodate Municipal Hospital, Hokkaido, Japan
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el Kalla S, Mathews AR, Menon NS. del(18p) syndrome with complex tetralogy of Fallot in an infant with 45,X,t(Y;18)(q12;q11.2). AMERICAN JOURNAL OF MEDICAL GENETICS 1992; 42:665-6. [PMID: 1632434 DOI: 10.1002/ajmg.1320420507] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report on an infant with multiple congenital anomalies, tetralogy of Fallot, and Karyotype 45,X,t(Y;18)(q12;11.2). The infant's anomalies are consistent with a del(18p) syndrome, except for the exceptional severity of the heart defect.
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Affiliation(s)
- S el Kalla
- Department of Pediatrics and Genetics, Al Wasl Maternity and Pediatric Hospital, Dubai, United Arab Emirates
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