Interestingly, CNV testing and exome sequencing have so far yielded mostly nonoverlapping genes, which might reflect different mutational mechanisms, although they might still perturb connected biological pathways.17 Although numerous ASD-associated loci have been recognized to date,18 they only account for a small fraction of the overall estimated heritability, consistent with predictions that there might be ∼1,000 loci underlying ASD19 and that many associated genes and risk variants remain to be identified.