Case of 45,X/48,XY mosaicism with non-mosaic discordance between short-term villi (45,X) and cultured villi (46,XY)

We report on a prenatally detected case of discordant non-mosaic karyotypes following chorionic villus sampling. A 45,X karyotype was found in cytotro phoblast cells and a 46,XY karyotype in mesenchymal core cells, A subsequen t amniocentesis showed a true 45,X/46,XY mosaicism, Confirmatory studies, i ncluding fluorescence in situ hybridization (FISH) in various fetal and pla cental tissues as well as in the original villi preparations changed the pr esumed condition of generalized mosaicism with culture confined normality t o that of generalized mosaicism with absolute concordance. This case unders cores the importance of the investigation of both short-term and cultured v illi preparations, the implementation of prenatal FISH studies, and the nee d for thorough follow-up investigation in cases of discrepant results. Am. J, Med, Genet, 93:230-233, 2000, (C) 2000 Wiley-Liss, Inc.