Exchange of terminal portions of X- and Y-chromosomal short arms in human XY females.
Human Y(+) XX maleness has been shown to result from an abnormal terminal Xp-Yp interchange that can occur during paternal meiosis. To test whether human XY females are produced by the same mechanism, we followed the inheritance of paternal pseudoautosomal loci and Xp22.3-specific loci in two XY female patients. Y-specific sequences and the whole pseudoautosomal region of the Y chromosome of their fathers were absent in these patients. However, the entire pseudoautosomal region and the X-specific part of Xp22.3 distal to the STS locus had been inherited from the X chromosome of the respective father. This Xp transfer to Yp was established by in situ hybridization experiments showing an Xp22.3-specific locus on Yp in both cases. Such results demonstrate that an abnormal and terminal X-Y interchange generated the rearranged Y chromosome of these two XY females; they appear to be the true countertype of Y(+) XX males. In these patients, who also display some Turner stigmata, the Y gene(s) involved in this phenotype is (are) localized to interval 1 or 2. If the loss of such gene(s) affects fetal viability, their proximity to TDF would account for the underrepresentation of interchange 46,XY females compared with Y(+) XX males.
Levilliers
J
J
Institut National de la Santé et de la Recherche Médicale U163, Centre National de la Recherche Scientifique UA 271, Paris, France.
Quack
B
B
Weissenbach
J
J
Petit
C
C
D015139:Blotting, Southern; D002872:Chromosome Deletion; D005260:Female; D006801:Humans; D007621:Karyotyping; D008297:Male; D008540:Meiosis; D009030:Mosaicism; D012729:Sex Chromosome Aberrations; D014960:X Chromosome; D014998:Y Chromosome