Duplications of the X chromosome in males: evidence that most parts of the X chromosome can be active in two copies.
We have analysed two duplications of the X chromosome in male patients using chromosome replication and DNA methylation patterns as determinants of the functional status of the duplicated segments. In both cases, the large duplicated regions, Xq12-q22 and Xq26.3-qter, were not inactivated. A review of previously reported male cases revealed that these duplications were also not subject to inactivation. Taken together, the examined duplications cover almost the entire X chromosome except the pericentromeric region and Xq25-26. Thus, most regions of the X chromosome can be present in two functional copies without lethal consequences.
Schmidt
M
M
Murdoch Institute, VCGS, Royal Children's Hospital, Melbourne, Australia.
Du Sart
D
D
Kalitsis
P
P
Leversha
M
M
Dale
S
S
Sheffield
L
L
Toniolo
D
D
D015139:Blotting, Southern; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D004247:DNA / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008745:Methylation; D005810:Multigene Family; D015183:Restriction Mapping; D014960:X Chromosome
D004247:DNA