DNA methylation is important for proper neuronal development and improper DNA methylation is associated with numerous neurological disorders such as autism and intellectual disability. The proposed research will utilize genomic approaches to examine how disease mutations in DNA methyltransferase 3a (DNMT3A) lead to altered neuronal methylation and investigate how loss of DNMT3A affects neuronal transcription. This work will establish how DNMT3A functions in healthy and diseased neurons to carefully regulate transcription in a cell-type-specific manner.