Evidence of a mechanism for isodicentric chromosome Y formation in a 45,X/46,X,idic(Y)(p11.31)/46,X,del(Y)(p11.31) mosaic karyotype.

Abnormalities involving sex chromosomes account for approximately 0.5% of live births. The phenotypes of individuals with mosaic cell lines having structural aberrations of the X and Y chromosomes are variable and hard to accurately predict.