Notably, alterations to genes within these pathways involving transcriptional regulation have been reproducibly implicated in ASD and more broadly defined NDDs [8, 10, 20–23], and multiple studies have also suggested protein-protein interactions (PPI) between MBD5 and the products of other NDD associated genes, including interaction with KDM1B within the PR-DUB polycomb protein complex [24], as well as regulatory interactions between MBD5 transcripts and FMRP (FMR1) [25], although the mechanisms by which such interactions contribute to abnormal neurodevelopment are not well understood. This evidence concerns the gene FMR1 and Neurodevelopmental delay.