X XY mosaicism in which X somatic cells are
45,X/46,XY mosaicism, in which 45,X somatic TAE226 are present at a high concentration, is very rare in the general population with an incidence rate of around 1.5/10,000 (Chang et al, 1990 and Moussaif et al, 2011). Depending on the concentration of somatic 45,X cells, individuals exhibit a wide range of phenotypic abnormalities from males with apparently normal phenotypes, men with short stature and gonadal failure, to women with Turner syndrome (Gantt et al, 1980, Layman et al, 2009, Newberg et al, 1998 and Telvi et al, 1999). Anaphase lag during the first mitotic division is the simplest explanation for 45,X/46,XY mosaicism, where one of the Y sister chromatids fails to be included in the daughter cells (Lukasa et al, 1986 and Telvi et al, 1999). This mitotic error may result in a 50:50 split 45,X/46,XY mosaicism in the individual\'s somatic cells. A mosaic 45,X/46,XY karyotype is often accompanied by a rare sexual development disorder termed mixed gonadal dysgenesis (MGD). Adults with MGD may vary in degree of infertility depending on the amount of mosaicism (Brosman, 1979). In rare MGD cases, spermatozoa are present and intracytoplasmic sperm injection (ICSI) is sought for fertility treatment. However, there have been very few MGD cases that resulted in successful conceptions, and the genetic transmission of chromosomal abnormalities in the spermatozoa remains a concern (Arnedo et al, 2005 and Bofinger et al, 1999). To better understand the production of aneuploid spermatozoa in these mosaic individuals, it is crucial to study the behaviours of the abnormal cell lines during meiosis.