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isochromosomes

Wednesday 25 August 2004

Isochromosome formation results when one arm of a chromosome is lost and the remaining arm is duplicated, resulting in a chromosome consisting of two short arms only or of two long arms.

An isochromosome has morphologically identical genetic information in both arms.

The most common isochromosome present in live births involves the long arm of the X and is designated i(X)(q10). The Xq isochromosome is associated with monosomy for genes on the short arm of X and with trisomy for genes on the long arm of X.

Isochromosomes are observed in 10% of cancer cytogenetic examinations

i(17q) i(8q) i(1q) i(12p) i(6p) i(7q) i(9q) i(5p) i(21q)

By tumors

acute myeloid leukemia i(11q) i(17q) i(21q)
chronic myeloid leukemia i(9q) i(17q) i(22q)
chronic myeloproliferative disorders i(17q)
myelodysplastic syndromes i(X)(q13) i(17q) i(21q)
acute lymphoblastic leukemia i(7q) i(9q) i(17q)
chronic lymphoproliferative disorders i(1q) i(7q) i(8q
Hodgkin disease i(1q) i(6p) i(9p) i(17q) i(21q)
non-Hodgkin lymphoma i(1q) i(6p) i(17q)
adenocarcinoma i(1q) i(8q) i(17q)
transitional cell carcinoma i(5p) i(8q) i(11q)
Wilms tumor i(1q) i(7q) i(17q)
germ cell neoplasms i(1q) i(12p) i(17q)
sarcoma i(1p) i(1q) i(6p) i(17q)
mesothelioma i(5p) i(6p) i(7p) i(21q)
malignant neurogenic neoplasms i(1q) i(6p) i(17q)
retinoblastoma i(1q) i(6p) i(17q)
malignant melanoma a i(1q) i(6p) i(8q)

References

- Mertens F, Johansson B, Mitelman F. Isochromosomes in neoplasia. Genes Chromosomes Cancer. 1994 Aug;10(4):221-30. PMID: 7522535