These associations were found despite exclusion of dDNVs and pLOFs in chromatin-modifying genes known to be associated with NDD risk, such as CHD7 and KMT2D. Our findings are consistent with prior studies from the overall PCGC cohort that found associations between damaging variants in chromatin-modifying genes and adverse ND outcomes assessed with only dichotomous screening questions in a medical history questionnaire.16 Chromatin-modifying genes regulate gene expression by altering the accessibility of DNA for transcription. This evidence concerns the gene CHD7 and Norrie disease.