A 36 year old white female was referred for chorionic villus sampling for advanced maternal age. Direct (cytotrophoblast) preparations of chorionic villi were 45,X, but cultured mesenchymal core cells from the same villi were 46,XX. Study of embryonic and extraembryonic tissues showed the aneuploidy to be limited to cytotrophoblasts from specific placental sites. In aggregate, the cytogenetic f...
