U-type exchange in a paracentric inversion as a possible mechanism of origin of an inverted tandem duplication of chromosome 8.
A mentally retarded male with dysmorphic features was found to have a de novo 46,XY,inv dup(8) (p.23.1-->12). Confirmation of the segments duplicated in the rearrangement was achieved by biochemical analysis of glutathione reductase, which maps to 8p21.1, and DNA studies using the chromosome specific probe y-19-1D (D85131), which maps to 8p21. Assay of cathepsin B, which has been localised to 8p22, did not differ from controls with normal chromosomal constitution. DNA studies using the Defensin 1 gene probe, which maps to 8p23, showed a previously undetected deletion of that segment. We propose that the inverted tandem duplication/deletion arose as a single U-type exchange within an inversion loop.
Mitchell
J J
JJ
Divisions of Medical Genetics, Montreal Children's Hospital, McGill Centre for Human Genetics, Quebec, Canada.
Vekemans
M
M
Luscombe
S
S
Hayden
M
M
Weber
B
B
Richter
A
A
Sparkes
R
R
Kojis
T
T
Watters
G
G
Der Kaloustian
V M
VM
D000015:Abnormalities, Multiple / Q000235:genetics; D002675:Child, Preschool; D007446:Chromosome Inversion; D002898:Chromosomes, Human, Pair 8; D005145:Face / Q000002:abnormalities; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D008297:Male; D005810:Multigene Family