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

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

Noomen, P., van den Berg, C., de Ruyter, J., Van Opstal, D., & 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