Confined placental mosaicism and the association with pregnancy outcome and fetal growth: a review of the literature.

Background: Chromosomal mosaicism can be detected in different stages of early life: in cleavage stage embryos, in blastocysts and biopsied cells from blastocysts during preimplantation genetic testing for aneuploidies (PGT-A) and later during prenatal testing, as well as after birth in cord blood. Mosaicism at all different stages can be associated with adverse pregnancy outcomes. There is an onward discussion about whether blastocysts diagnosed as chromosomally mosaic by PGT-A should be considered safe for transfer.

Enlarged NT (≥3.5 mm) in the first trimester - not all chromosome aberrations can be detected by NIPT.

Background: Since non-invasive prenatal testing (NIPT) in maternal blood became available, we evaluated which chromosome aberrations found in our cohort of fetuses with an enlarged NT in the first trimester of pregnancy (tested with SNP microarray) could be detected by NIPT as well.

Method: 362 fetuses were referred for cytogenetic testing due to an enlarged NT (≥3.5 mm).

Prenatal diagnosis of alobar holoprosencephaly, cyclopia, proboscis, and isochromosome 18q in the second trimester.

We would like to present a rare case of alobar holoprosencephaly (HPE) in a fetus diagnosed by routine sonography in the second trimester. Structural sonography demonstrated multiple facial anomalies including absent nasal bone, flat facial profile, hypotelorism, fusion of the orbits and proboscis. After counseling, termination of pregnancy was performed by vaginally administered misoprostol.

Comparison of multiplex ligation-dependent probe amplification and karyotyping in prenatal diagnosis.

Objective: To estimate whether multiplex ligation-dependent probe amplification (MLPA), a molecular technique used for detecting the most common chromosomal aneuploidies, is comparable with karyotyping for the detection of aneuploidies of chromosomes X, Y, 13, 18, and 21 in routine clinical practice and to estimate the costs differences of both techniques.

Methods: In this prospective, nationwide cohort study, we consecutively included 4,585 women who had an amniocentesis because of their age (36 years or older), increased risk after prenatal screening, or maternal anxiety. Amniotic fluid samples were tested independently with both MLPA and karyotyping.

(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.