False Negative NIPT Results: Risk Figures for Chromosomes 13, 18 and 21 Based on Chorionic Villi Results in 5967 Cases and Literature Review.

Non-invasive prenatal testing (NIPT) demonstrated a small chance for a false negative result. Since the "fetal" DNA in maternal blood originates from the cytotrophoblast of chorionic villi (CV), some false negative results will have a biological origin. Based on our experience with cytogenetic studies of CV, we tried to estimate this risk.

Rapid aneuploidy detection with multiplex ligation-dependent probe amplification: a prospective study of 4000 amniotic fluid samples.

The introduction of prenatal screening requires rapid high-throughput diagnosis of common aneuploidies. Multiplex ligation-dependent probe amplification (MLPA) allows for quick, easily automated multiplex testing of these aneuploidies in one polymerase chain reaction. We performed a large prospective study using MLPA on 4000 amniotic fluid (AF) samples including all indications and compared its value to karyotyping and fluorescence in situ hybridization (FISH).

(Potential) false-negative diagnoses in chorionic villi and a review of the literature.

Objectives: To assess the incidence of (potential) false-negative findings of cytogenetic diagnosis in STC-villi and/or LTC-villi and to determine the best strategy for karyotyping chorionic villi in order to avoid false-negative results.

Methods: 2476 chorionic villus samples were received for prenatal cytogenetic investigations. Karyotyping was routinely performed on STC- and LTC-villi preparations by G-banding.

The development of cytogenetically normal, abnormal and mosaic embryos: a theoretical model.

Assisted reproduction and preimplantation genetic diagnosis (PGD) involve various complicated techniques, each of them with its own problems. However, the greatest problem with PGD for chromosome abnormalities is not of a technical nature but is a biological phenomenon: chromosomal mosaicism in the cleavage stage embryo. Here, we present a hypothetical, quantitative model for the development of chromosomally normal, abnormal and mosaic embryos.