Partial trisomy 13 presumably due to recombination in an inversion heterozygote and by unequal crossing-over.
Two unrelated infants with partial trisomy 13 for the distal of the long arm are described. In one, a familial pericentric inversion is present in three generations and crossing-over in the inversion loop is considered as cause of partial trisomy 13. The other showed a tandem duplication of the distal half of the long arm of chromosome 13 beyond 13q14. This is interpreted to have arisen by unequal crossing-over in mispaired synapsis. It is suggested that recombination rather than breaks is a distinctive although rare cause of human chromosomal imbalance.
D007446:Chromosome Inversion; D002901:Chromosomes, Human, 13-15; D003434:Crossing Over, Genetic; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D008297:Male; D011995:Recombination, Genetic; D014314:Trisomy