A dicentric recombinant 9 derived from a paracentric inversion: phenotype, cytogenetics, and molecular analysis of centromeres.
A 4-year-old girl with multiple malformations and severe developmental delay has been shown to have a karyotype of 46,XX-9,+rec(9),dup p,inv(9) (q22.1q34.3)mat, with duplication 9pter-q22.1 and deficiency 9q34.3-qter. This case confirms that a stable recombinant chromosome can result from a paracentric inversion. The recombinant was derived by two crossovers, one within the inversion loop and a second outside the inversion loop, between 9q21 and the beginning of the meiotic inversion at 9q22.1. In 87 cells the rec(9) had one Cd-positive primary constriction. In 13 cells the rec(9) had two primary constrictions; in 12 of these cells there was one Cd-positive centromere, and in one of these cells both primary constrictions were Cd-positive. Nuclear projections were observed in 10% of fibroblast interphase cells harvested in situ, suggesting that there was some spindle-fiber activity of the "latent" centromere. In situ hybridization with a centromere-specific probe (p82H) and a satellite III probe (L6) revealed no differences between the two C-band regions of the rec(9) and the normal 9 or inverted 9 chromosomes.
Worsham
M J
MJ
Medical Genetics and Birth Defects Center, Henry Ford Hospital, Detroit, MI 48202.
Miller
D A
DA
Devries
J M
JM
Mitchell
A R
AR
Babu
V R
VR
Surli
V
V
Weiss
L
L
Van Dyke
D L
DL
D000015:Abnormalities, Multiple / Q000235:genetics*; D002503:Centromere; D002675:Child, Preschool; D002871:Chromosome Banding; D007446:Chromosome Inversion; D002875:Chromosomes; D002899:Chromosomes, Human, Pair 9; D015342:DNA Probes; D005260:Female; D006801:Humans; D007621:Karyotyping; D008297:Male; D009693:Nucleic Acid Hybridization; D010375:Pedigree; D010641:Phenotype; D014314:Trisomy
D015342:DNA Probes