NIPT-based screening for Down syndrome and beyond: what do pregnant women think?

The aim of the study is to study pregnant women's views on noninvasive prenatal testing (NIPT) for Down syndrome and the potential to test for a broader range of conditions. An online questionnaire available on the Dutch pregnancy fair website was completed by 381 pregnant women. Of the women, 51% expressed interest in having NIPT, including 33% of women who had declined first-trimester screening. The majority (73%) thought that the uptake of screening would increase with NIPT. Most women agreed that testing for life-threatening (89%), severe physical (79%), or severe mental (76%) disorders should be offered. A minority (29%) felt that prenatal screening should also be offered for late-onset disorders. Most (41%) preferred to have a free choice from a list of disorders, 31% preferred a 'closed offer', and 26% preferred choosing between packages of disorders. Although most women (76%) thought that screening for a broad range of conditions would avoid much suffering, 39% feared that it would confront couples with choices, the implications of which would be difficult to grasp. The results suggest that the uptake of screening will increase with NIPT. If NIPT will be offered for a broad range of conditions, it is crucial to find a way that facilitates rather than undermines well-informed decision-makin

Compromised transcription-mRNA export factor THOC2 causes R-loop accumulation, DNA damage and adverse neurodevelopment

Abstract We implicated the X-chromosome THOC2 gene, which encodes the largest subunit of the highly-conserved TREX (Transcription-Export) complex, in a clinically complex neurodevelopmental disorder with intellectual disability as the core phenotype. To study the molecular pathology of this essential eukaryotic gene, we generated a mouse model based on a hypomorphic Thoc2 exon 37–38 deletion variant of a patient with ID, speech delay, hypotonia, and microcephaly. The Thoc2 exon 37–38 deletion male (Thoc2 Δ/Y ) mice recapitulate the core phenotypes of THOC2 syndrome including smaller size and weight, and significant deficits in spatial learning, working memory and sensorimotor functions. The Thoc2 Δ/Y mouse brain development is significantly impacted by compromised THOC2/TREX function resulting in R-loop accumulation, DNA damage and consequent cell death. Overall, we suggest that perturbed R-loop homeostasis, in stem cells and/or differentiated cells in mice and the patient, and DNA damage-associated functional alterations are at the root of THOC2 syndrome

ANK2 loss-of-function variants are associated with epilepsy, and lead to impaired axon initial segment plasticity and hyperactive network activity in hiPSC-derived neuronal networks

PURPOSE: To characterize a novel neurodevelopmental syndrome due to loss-of-function (LoF) variants in Ankyrin 2 (ANK2), and to explore the effects on neuronal network dynamics and homeostatic plasticity in human-induced pluripotent stem cell-derived neurons.METHODS: We collected clinical and molecular data of 12 individuals with heterozygous de novo LoF variants in ANK2. We generated a heterozygous LoF allele of ANK2 using CRISPR/Cas9 in human-induced pluripotent stem cells (hiPSCs). HiPSCs were differentiated into excitatory neurons, and we measured their spontaneous electrophysiological responses using micro-electrode arrays (MEAs). We also characterized their somatodendritic morphology and axon initial segment (AIS) structure and plasticity.RESULTS: We found a broad neurodevelopmental disorder (NDD), comprising intellectual disability, autism spectrum disorders and early onset epilepsy. Using MEAs, we found that hiPSC-derived neurons with heterozygous LoF of ANK2 show a hyperactive and desynchronized neuronal network. ANK2-deficient neurons also showed increased somatodendritic structures and altered AIS structure of which its plasticity is impaired upon activity-dependent modulation.CONCLUSIONS: Phenotypic characterization of patients with de novo ANK2 LoF variants defines a novel NDD with early onset epilepsy. Our functional in vitro data of ANK2-deficient human neurons show a specific neuronal phenotype in which reduced ANKB expression leads to hyperactive and desynchronized neuronal network activity, increased somatodendritic complexity and AIS structure and impaired activity-dependent plasticity of the AIS.</p