isochromosome

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isochromosome

 [i″so-kro´mo-sōm]
an abnormal chromosome having a median centromere and two identical arms, formed by transverse, rather than normal longitudinal, splitting of a replicating chromosome.

i·so·chro·mo·some

(ī'sō-krō'mō-sōm),
A chromosomal aberration that arises as a result of transverse rather than longitudinal division of the centromere during meiosis; two daughter chromosomes are formed, each lacking one chromosome arm but with the other doubled.

i·so·chro·mo·some

(ī'sō-krō'mŏ-sōm)
A chromosomal aberration that arises as a result of transverse rather than longitudinal division of the centromere during meiosis; two daughter chromosomes are formed, each lacking one chromosome arm but with the other doubled.

isochromosome

An abnormal chromosome formed when, during the ANAPHASE of cell division, the CENTROMERE divides horizontally rather than longitudinally, thus producing a chromosome with two long arms and one with two short arms.
References in periodicals archive ?
UPD associated with an isochromosome was reported in cases with i(1p) plus i(1q), i(2p) plus i(2q), i(4p) plus i(4q), i(7p) plus i(7q), psudic (8)(p23.3), i(9p) plus i(9q), i(13q), i(14q), i(15q), i(21q), and i(22q) (35, 36).
Recurrent abortion associated with a balanced 22;22 translocation, or isochromosome 22q in a monozygous twin.
In a number of individuals with reduced chiasma frequency, both ring-univalents and fold-back bivalents (i.e., those where one arm of a metacentric formed chiasmata both with its second arm and with its homologue) were found, indicating the presence of duplicate terminal segments within single chromosomes, which in turn might suggest the presence of a pair of isochromosomes.
An awareness of isochromosomes and their implications has also been shown to be informative in detecting hidden polyploidy.
With just these 3 chromosomes, the most common blast crisis-related changes--that is, trisomy 8, isochromosome for the long arm of 17, and additional copies of the Philadelphia chromosome--can be assessed.
H, A dicentric isochromosome of the chromosome 17 long arm with concomitant loss of the short arm.