Objective: Investigation of the normal frequency of tetraploid metaphases in semidirect (STC) and cultured (LTC) chorionic villi. Methods: Fifty metaphases in STC- and in LTC-villi slides of 100 women of advanced maternal age were screened for tetraploidy. Results: Up to three tetraploid metaphases were encountered in 27% of the STC-villi preparations; the scores fitted a Poisson distribution. In all LTC-villi preparations tetraploid cells were seen; the scores fitted a log-Gaussian distribution. Conclusions: On the basis of these distributions, we propose a protocol for the management of tetraploid metaphases in chorionic villi, strongly reducing the number of prenatal follow-up investigations. Copyright

Chorionic villi, Mosaicism, Tetraploidy
dx.doi.org/10.1159/000053896, hdl.handle.net/1765/66308
Fetal Diagnosis and Therapy
Department of Clinical Genetics

Noomen, P, van den Berg, C.D.F, de Ruyter, J.L.M, Van Opstal, A.R.M, & Los, F.J. (2001). Prevalence of tetraploid metaphases in semidirect and cultured chorionic villi. Fetal Diagnosis and Therapy, 16(3), 129–132. doi:10.1159/000053896