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This article discusses a study that aims to demonstrate the scientific validity of a novel cell-based non-invasive prenatal testing (cbNIPT) method for detecting fetal copy number variants (CNVs) using single cell sequencing of circulating extravillous trophoblasts (cEVTs). The study enrolled 1388 high-risk pregnancies and found a screen positive rate of 18.9% for aneuploidies and 11.2% for pCNVs. The results showed that cbNIPT was able to detect pCNVs <1 Mb in size, which is below the resolution of cell-free DNA screening. The authors conclude that analyzing cEVTs from maternal blood could significantly reduce the residual risk for pCNVs in early gestational weeks. [Extracted from the article]

Since identification of women at risk of NIPT failure is crucial in counseling, we evaluated the feasibility of using a machine learning (ML) model based on maternal and fetal characteristics to predict low FF. Although non-invasive prenatal testing (NIPT) based on cell-free fetal DNA fragments in maternal blood samples is a well-established method for aneuploidy screening, in approximately 4% of women NIPT fails to return a result due to an insufficient fetal fraction (FF) cell-free DNA in maternal plasma. VP17.03: Prediction of low fetal fraction in maternal blood cell-free DNA using a machine learning model. [Extracted from the article]

Pallister-Killian syndrome (PKS-#OMIM601803) is a multisystem developmental disorder typically due to the presence of an aneuploidy cell line, consisting of a supernumerary tetrasomic chromosomal marker (SCM) arisen from the short arm of chromosome 12 (12p isochromosome). The clinical phenotype, which is strictly related to the percentage and tissue distribution of aneuploid cells, is characterized by craniofacial dysmorphisms, pigmentary skin anomalies, limb shortening, congenital heart defects, diaphragmatic hernia, hypotonia, intellectual disability, and epilepsy. We report on a 4 year-old girl harboring a 12p partial isochromosome, involving the PKS critical region, affecting about 70% of circulating lymphocytes, urine, and saliva cells and fibroblast from a hyperpigmented skin spot, and 100% of fibroblasts from a hypopigmented skin spot. Interestingly, despite the high proportion of affected cells this patient did not present with PKS, and a pattern of linear and patchy pigmentary mosaicism was the sole clinical manifestation. The present observation suggests that partial 12p SCM can also result in mild phenotypes, and its prevalence in the human population could have been underestimated. Accurate dermatologic evaluation could be a major handle for genetic testing., (© 2017 Wiley Periodicals, Inc.)