Dissociation of tdic chromosomes: about a t(15;18)(p11;p11) leading to 18p monosomy.
A 10-month-old girl with monosomy due to a de novo 45,XX,-15,-18,+tdic(15;18)(p11;p11) karyotype is described. The abnormal chromosome underwent dissociation into two telocentrics in 5/200 (2.5%) metaphases. This and other comparable instances indicate that, in addition to criss-cross separation of the dicentric chromatids, the characteristics of the anomalous reunion also influence the rate of dissociation. Besides, the mean maternal (31.2) and paternal (35.1) ages in this subtype of 18p monosomy are significantly increased.
D002871:Chromosome Banding; D002872:Chromosome Deletion; D002884:Chromosomes, Human, Pair 15; D002887:Chromosomes, Human, Pair 18; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D009006:Monosomy; D014178:Translocation, Genetic