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Female predominance (low sex ratio) in 47,+21 mosaics

✍ Scribed by Hook, Ernest B.; Cross, Philip K.; Mutton, David E.


Publisher
John Wiley and Sons
Year
1999
Tongue
English
Weight
25 KB
Volume
84
Category
Article
ISSN
0148-7299

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✦ Synopsis


Data from the New York State Chromosome

Registry on over 10,000 cases of Down syndrome reported from 1977 to 1996 confirm findings in the England and Wales Cytogenetic Register that in mosaic 46/47,+21 cases of Down syndrome the male/female ratio (as inferred from XY and XY karyotypes respectively) is less than 1.0 as opposed to the ratio in nonmosaic 47,+21 cases in which the ratio is close to 1.2, or in the general background population with ratio of about 1.05. These results may reflect in part differential pairing in 47,+21 somatic cells of X and Y chromosomes with a 21 chromosome and/or in in-utero selection.