No mouse knockout information was reported for PRR23A or PRSS22. Finally, a look-up in results from EWASs of neurodevelopmental outcomes including ADHD symptoms, autism spectrum disorder (ASD), and IQ showed that DNA methylation at the three identified CpGs was not associated with these outcomes (Additional file 1: Table S14) [25–27]. This evidence concerns the gene PRSS22 and attention deficit-hyperactivity disorder.