The DNA demethylase TET1 modifies the impact of maternal folic acid status on embryonic brain development.

Folic acid (FA) is well known to prevent neural tube defects (NTDs), but we do not know why many human NTD cases still remain refractory to FA supplementation. Here, we investigate how the DNA demethylase TET1 interacts with maternal FA status to regulate mouse embryonic brain development. We determined that cranial NTDs display higher penetrance in non-inbred than in inbred Tet1 embryos and are resistant to FA supplementation across strains.

Epigenetic regulation by TET1 in gene-environmental interactions influencing susceptibility to congenital malformations.

The etiology of neural tube defects (NTDs) involves complex gene-environmental interactions. Folic acid (FA) prevents NTDs, but the mechanisms remain poorly understood and at least 30% of human NTDs resist the beneficial effects of FA supplementation. Here, we identify the DNA demethylase TET1 as a nexus of folate-dependent one-carbon metabolism and genetic risk factors post-neural tube closure.

Effectiveness of Omicron XBB.1.5 vaccine against infection with SARS-CoV-2 Omicron XBB and JN.1 variants, prospective cohort study, the Netherlands, October 2023 to January 2024.

We estimated vaccine effectiveness (VE) of SARS-CoV-2 Omicron XBB.1.5 vaccination against self-reported infection between 9 October 2023 and 9 January 2024 in 23,895 XBB.

Analysis of two sequential SARS-CoV-2 outbreaks on a haematology-oncology ward and the role of infection prevention.

Two SARS-CoV-2 nosocomial outbreaks occurred on the haematology ward of our hospital. Patients on the ward were at high risk for severe infection because of their immunocompromised status. Whole Genome Sequencing proved transmission of a particular SARS-CoV-2 variant in each outbreak.

High quality of SARS-CoV-2 molecular diagnostics in a diverse laboratory landscape through supported benchmark testing and External Quality Assessment.

A two-step strategy combining assisted benchmark testing (entry controls) and External Quality Assessments (EQAs) with blinded simulated clinical specimens to enhance and maintain the quality of nucleic acid amplification testing was developed. This strategy was successfully applied to 71 diagnostic laboratories in The Netherlands when upscaling the national diagnostic capacity during the SARS-CoV-2 pandemic. The availability of benchmark testing in combination with advice for improvement substantially enhanced the quality of the laboratory testing procedures for SARS-CoV-2 detection.