Placental mosaicism for autosomal trisomies: comprehensive follow-up of 528 Danish cases (1983-2021).

Background: Mosaicism, characterized by the presence of two or more chromosomally distinct cell lines, is detected in 2% to 4% of chorionic villus samples (CVSs). In these cases, the aberration may be confined to the placenta or additionally present in the fetus. Fetal involvement may manifest as fetal malformations, while confined placental mosaicism (CPM) poses risks such as preterm birth and low birth weight.

Use of cell-free non-invasive prenatal testing in pregnancies affected by placental mosaicism.

Objective: To evaluate cell-free non-invasive prenatal testing (cfNIPT) in pregnancies affected by mosaicism.

Method: We assessed paired cfNIPT and chorionic villus sample (CVS) results from the same pregnancies in a case series of mosaicism detected in Central and North Denmark Regions from April 2014 to September 2018. Indications for the clinically obtained CVS, pregnancy markers and outcome were retrieved from The Danish Fetal Medicine Database.

Incidental finding of maternal malignancy in an unusual non-invasive prenatal test and a review of similar cases.

We present a clinical case where a complex abnormal non-invasive prenatal test (NIPT) result in a research project revealed carcinoma of the breast in the pregnant woman. Furthermore, the NIPT result did not demonstrate the same fetal chromosomal aberration as the chorion villus sample. A literature search for similar cases was performed identifying 43 unique cases, where abnormal NIPT results were related to maternal malignancy.

Mosaicism for copy number variations in the placenta is even more difficult to interpret than mosaicism for whole chromosome aneuploidy.

Objective: To compare mosaicisms in prenatal chorionic villus samples (CVSs) with corresponding postpartum placental samples.

Method: We collected placentas from 15 consecutive cases of mosaicism detected in CVSs and obtained five standardized samples on each placenta after delivery. All pre- and postnatal placental samples were uncultured and analyzed by high-resolution chromosomal microarray.

Trisomy 8 mosaicism in the placenta: A Danish cohort study of 37 cases and a literature review.

Objective: To evaluate the risk of fetal involvement when trisomy 8 mosaicism (T8M) is detected in chorionic villus samples (CVS).

Methods: A retrospective descriptive study of registered pregnancies in Denmark with T8M in CVS identified through a database search and a review of published cases of T8M found through a systematic literature search and inclusion of cross references. Pregnancies with T8M in CVS and no additional numerical chromosomal aberrations were included.

National data on the early clinical use of non-invasive prenatal testing in public and private healthcare in Denmark 2013-2017.

Introduction: In Denmark, non-invasive prenatal testing (NIPT) has been used since 2013. We aimed to evaluate the early clinical use of NIPT in Danish public and private healthcare settings before NIPT became an integrated part of the national guidelines on prenatal screening and diagnosis in 2017.

Material And Methods: NIPT data were collected between March 2013 and June 2017 from national public registries and private providers.

Prevalence of mosaicism in uncultured chorionic villus samples after chromosomal microarray and clinical outcome in pregnancies affected by confined placental mosaicism.

Objective: To evaluate the prevalence of mosaicism in chorionic villus sampling (CVS) samples after chromosomal microarray (CMA) and clinical outcome of pregnancies affected by confined placental mosaicism.

Method: We retrieved all results from CMA, array-based comparative genomic hybridization, on CVS samples from January 2011 to November 2017 from Central and North Denmark Regions. Mosaic results from uncultured chorionic villi, cytotrophoblasts and mesenchymal cells, after CVS and follow-up on amniocytes, fetal tissue, or postnatal blood were studied and matched with clinical data from The Danish Fetal Medicine Database.

The spectrum of intermediate SCN8A-related epilepsy.

Objective: Pathogenic variants in SCN8A have been associated with a wide spectrum of epilepsy phenotypes, ranging from benign familial infantile seizures (BFIS) to epileptic encephalopathies with variable severity. Furthermore, a few patients with intellectual disability (ID) or movement disorders without epilepsy have been reported. The vast majority of the published SCN8A patients suffer from severe developmental and epileptic encephalopathy (DEE).

Preferences for prenatal testing among pregnant women, partners and health professionals.

Introduction: Cell-free DNA testing (cfDNA testing) in maternal plasma has recently been implemented in Danish healthcare. Prior to that we wanted to evaluate the preferences among pregnant women, partners and health professionals regarding cfDNA testing compared with invasive prenatal diagnostics.

Methods: Responders were recruited at public hospitals in the Central and North Denmark Regions.

National screening guidelines and developments in prenatal diagnoses and live births of Down syndrome in 1973-2016 in Denmark.

Introduction: Denmark was the first country in the world to implement a national, free-for-all offer of prenatal screening for Down syndrome to all pregnant women. It has a high uptake (>90%) compared to other countries. Thus, Denmark offers an interesting case for investigating the consequences of implementing comprehensive, national prenatal screening guidelines.

Prenatal diagnosis of Nager syndrome in a 12-week-old fetus with a whole gene deletion of SF3B4 by chromosomal microarray.

Less than one hundred cases of the acrofacial dysostosis, Nager syndrome, have been described. The cardinal features of Nager syndrome are micrognathia, midface retrusion and limb malformations, predominately of the radial ray of upper extremities. Within the past three years haploinsufficiency of SF3B4 has been confirmed as the major cause of Nager syndrome.