Home LiteratureArticle Details
PMID: 16041583 Published · ppublish English Case Reports Journal Article Research Support, Non-U.S. Gov't

Reciprocal translocations: a trap for cytogenetists?

Human genetics ·Vol. 117 ·No. 6 ·2005-10-00 ·Pages 571-82

Ciccone R, Giorda R, Gregato G, Guerrini R, Giglio S, Carrozzo R, Bonaglia MC, Priolo E, Laganà C, Tenconi R, Rocchi M, Pramparo T, Zuffardi O, Rossi E

Abstract

We report four cases of subjects with phenotypic abnormalities and mental retardation associated with apparently balanced translocations, two inherited and two de novo, which showed, by molecular analysis, a hidden complexity. All the cases have been analyzed with different molecular techniques, including array-CGH, and in two of them the translocation breakpoints have been defined at the level of base pairs via studies in somatic hybrids containing single derivative chromosomes. We demonstrated that all the translocations were in fact complex rearrangements and that an imbalance was present in three of them, thus accounting for the phenotypic abnormalities. In one case, a Prader-Willi subject, we were not able to determine the molecular cause of his phenotype. This study, while confirming previous data showing unexpected complexity in translocations, further underscores the need for molecular investigations before taking for granted an apparently simple cytogenetic interpretation.

MeSH Terms
Abnormalities, Multiple/genetics Child Child, Preschool Chromosome Aberrations Female Gene Rearrangement Humans Intellectual Disability/genetics Male Oligonucleotide Array Sequence Analysis Prader-Willi Syndrome/genetics Translocation, Genetic
Authors & Affiliations
14 authors, click to expand affiliations / ORCID
Ciccone Roberto
Biologia Generale e Genetica Medica, Università di Pavia, Pavia, Italy.
Giorda Roberto
Gregato Giuliana
Guerrini Renzo
Giglio Sabrina
Carrozzo Romeo
Bonaglia Maria Clara
Priolo Emanuela
Laganà Carmelo
Tenconi Romano
Rocchi Mariano
Pramparo Tiziano
Zuffardi Orsetta
Rossi Elena
References (31)
31 references, click to expand
  1. De novo balanced chromosome rearrangements and extra marker chromosomes identified at prenatal diagnosis: clinical significance and distribution of breakpoints.
    Am J Hum Genet. 1991 Nov;49(5):995-1013 PMID: 1928105
  2. Fluorescence in situ hybridization characterization of apparently balanced translocation reveals cryptic complex chromosomal rearrangements with unexpected level of complexity.
    Eur J Hum Genet. 2004 Aug;12(8):647-53 PMID: 15162125
  3. A cryptic deletion of 2q35 including part of the PAX3 gene detected by breakpoint mapping in a child with autism and a de novo 2;8 translocation.
    J Med Genet. 2002 Jun;39(6):391-9 PMID: 12070244
  4. Somatic mosaicism in patients with Angelman syndrome and an imprinting defect.
    Hum Mol Genet. 2004 Nov 1;13(21):2547-55 PMID: 15385437
  5. Chromosomal abnormalities in mendelian disorders.
    Lancet. 1982 Aug 7;2(8293):322-3 PMID: 6124729
  6. Automated screening for genomic imbalances using matrix-based comparative genomic hybridization.
    Lab Invest. 2002 Jan;82(1):47-60 PMID: 11796825
  7. Prader-Willi syndrome: consensus diagnostic criteria.
    Pediatrics. 1993 Feb;91(2):398-402 PMID: 8424017
  8. De novo apparently balanced complex chromosome rearrangement (CCR) involving chromosomes 4, 18, and 21 in a girl with mental retardation: report and review.
    Am J Med Genet. 1998 Jun 16;78(1):44-51 PMID: 9637422
  9. Balanced translocation 46,XY,t(2;15)(q37.2;q11.2) associated with atypical Prader-Willi syndrome.
    Am J Hum Genet. 1997 Aug;61(2):388-94 PMID: 9311744
  10. Genome scanning with array CGH delineates regional alterations in mouse islet carcinomas.
    Nat Genet. 2001 Dec;29(4):459-64 PMID: 11694878
  11. Selective disruption of muscle and brain-specific BPAG1 isoforms in a girl with a 6;15 translocation, cognitive and motor delay, and tracheo-oesophageal atresia.
    J Med Genet. 2004 Jun;41(6):e71 PMID: 15173237
  12. De novo 9-break-event in one chromosome 21 combined with a microdeletion in 21q22.11 in a mentally retarded boy with short stature.
    Cytogenet Genome Res. 2003;103(1-2):14-6 PMID: 15004457
  13. Heterozygous submicroscopic inversions involving olfactory receptor-gene clusters mediate the recurrent t(4;8)(p16;p23) translocation.
    Am J Hum Genet. 2002 Aug;71(2):276-85 PMID: 12058347
  14. Unusual chromosomal mosaicism as a cause of mental retardation and congenital malformations in a familial reciprocal translocation carrier, t(17;22)(q24.2;q11.23).
    Cytogenet Cell Genet. 2001;93(3-4):168-70 PMID: 11528107
  15. Detection of large-scale variation in the human genome.
    Nat Genet. 2004 Sep;36(9):949-51 PMID: 15286789
  16. Microarray based comparative genomic hybridisation (array-CGH) detects submicroscopic chromosomal deletions and duplications in patients with learning disability/mental retardation and dysmorphic features.
    J Med Genet. 2004 Apr;41(4):241-8 PMID: 15060094
  17. Additional deletion in sex-determining region of human Y chromosome resolves paradox of X,t(Y;22) female.
    Nature. 1990 Jul 19;346(6281):279-81 PMID: 1973823
  18. Duchenne muscular dystrophy (DMD) in a female with an X/autosome translocation: further evidence that the DMD locus is at Xp21.
    Am J Hum Genet. 1981 Jul;33(4):513-8 PMID: 7258185
  19. Molecular analysis of a complex chromosomal rearrangement and a review of familial cases.
    Am J Med Genet. 1994 Nov 15;53(3):255-63 PMID: 7856662
  20. Exclusion of SNRPN as a major determinant of Prader-Willi syndrome by a translocation breakpoint.
    Nat Genet. 1996 Apr;12(4):452-4 PMID: 8630505
  21. High resolution R- and G-banding on the same preparation.
    Hum Genet. 1981;57(1):93-5 PMID: 7262875
  22. Recombination in a balanced complex translocation of a mother leading to a balanced reciprocal translocation in the child. Review of 60 cases of balanced complex translocations.
    Hum Genet. 1997 Jun;99(6):806-15 PMID: 9187678
  23. Disease associated balanced chromosome rearrangements: a resource for large scale genotype-phenotype delineation in man.
    J Med Genet. 2000 Nov;37(11):858-65 PMID: 11073540
  24. Mutations in SOX2 cause anophthalmia.
    Nat Genet. 2003 Apr;33(4):461-3 PMID: 12612584
  25. The complex nature of constitutional de novo apparently balanced translocations in patients presenting with abnormal phenotypes.
    J Med Genet. 2005 Jan;42(1):8-16 PMID: 15635069
  26. A translocation breakpoint cluster disrupts the newly defined 3' end of the SNURF-SNRPN transcription unit on chromosome 15.
    Hum Mol Genet. 2001 Feb 1;10(3):201-10 PMID: 11159938
  27. Prader-Willi syndrome is caused by disruption of the SNRPN gene.
    Am J Hum Genet. 1999 Jan;64(1):70-6 PMID: 9915945
  28. Characterization of breakpoints in the GABRG3 and TSPY genes in a family with a t(Y;15)(p11.2;q12).
    Am J Med Genet A. 2004 Mar 1;125A(2):177-80 PMID: 14981720
  29. Breakage in the SNRPN locus in a balanced 46,XY,t(15;19) Prader-Willi syndrome patient.
    Hum Mol Genet. 1996 Apr;5(4):517-24 PMID: 8845846
  30. Deficiency, transposition, and duplication of one 15q region may be alternatively associated with Prader-Willi (or a similar) syndrome. Analysis of seven cases after varying ascertainment.
    Hum Genet. 1983;64(4):388-94 PMID: 6618490
  31. Molecular characterization of two proximal deletion breakpoint regions in both Prader-Willi and Angelman syndrome patients.
    Am J Hum Genet. 1995 Jul;57(1):40-8 PMID: 7611294
Article Info
Journal
Human genetics
Abbr.
Hum Genet
ISSN
0340-6717
DOI
10.1007/s00439-005-1324-x
Published
2005-10-00
Epub
2005-00-23
Pages
571-82
Language
English
Region
Germany
NLM ID
7613873
Subset
IM
Grants
Telethon · GP0247Y01 · Italy
External Links
PubMed source DOI: 10.1007/s00439-005-1324-x View journal details
Analysis Services
Analysis Services

Contact

No. 2 Wenbo Road, Zhangqiu District, Jinan, Shandong

Qilu Normal University · Genelibs Bioinformatics Lab

750 Shunhua Rd, Jinan

2F, Bldg F, University Science Park

Tel: 0531-88819269

WeChat Official Account

Follow our WeChat subscription account for real-time updates and the latest in medical and biological research.


Business Email

E-mail: [email protected]

Copyright © 2026.Genelibs Jinan Honghui Biotechnology Co., Ltd. 鲁ICP备20007159号-2