De novo CNV is a contributing factor in 5–10% of patients. The contribution of de novo point mutation has not been fully explored but preliminary studies suggest the contribution of exomic de novo mutations to ASD to be similar (Ben Neale, Evan Eichler, Matthew State, http://www.broadinstitute.org/scientific-community/science/programs/psychiatric-disease/symposium/session-videos). All told, de novo mutation in coding regions appears to contribute in a significant but minor fraction (<20%) of ASD cases.
