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Post‐zygotic origin of isochromosome 12p
Author(s) -
de Ravel Thomy J. L.,
Keymolen Kathelijn,
van Assche Elvire,
Wittevronghel Ingrid,
Moerman Philippe,
Salden Ivo,
Matthijs Gert,
Fryns JeanPierre,
Vermeesch Joris R.
Publication year - 2004
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.956
Subject(s) - isochromosome , karyotype , biology , subtelomere , genetics , chromosome , fetus , zygote , cytogenetics , aneuploidy , microbiology and biotechnology , gene , pregnancy , embryogenesis
Objective Advance knowledge about the mechanism of isochromosome formation. Methods Echographic examination of the foetus. G‐ and/or T‐banded chromosome and FISH analysis using chromosome 12p subtelomeric probes on short‐ and long‐term CVS cultures, amniocytes and foetal fibroblasts. Polymorphic CA repeat analysis on DNA from the foetus and both parents. Results Short‐term CVS cultures showed a 46,XX karyotype, whilst long‐term CVS cultures showed a 47,XX,+12 karyotype. FISH on amniocytes indicated 2, 3 and 4 signals. Foetal fibroblasts showed both 47,XX,+12 and 47,XX,+i(12)(p10) karyotypes. DNA analysis revealed the isochromosome to be paternal in origin, whilst the other two foetal chromosomes 12 were maternal, part iso‐ and part heterodisomy. Conclusion The cytogenetic and DNA constitution of the foetus indicated the isochromosome 12p to be of paternal origin, and implied post‐zygotic formation of the isochromosome 12p in the Pallister–Killian syndrome. Copyright © 2004 John Wiley & Sons, Ltd.