Through discovery of point mutations, novel genome-wide sequencing approaches will pinpoint individual genes in disorders of cognitive development. These new approaches provide further precision regarding susceptibility mechanisms as compared to CNV studies. However, early sequencing studies already suggest that the heterogeneity of individual molecular causes will remain broad.74, 75 Early studies have already implicated genetic loci shared by multiple disorders. For example, de novo SCN1A have been discovered in autism.76, 77 SCN1A mutations had been previously well-known for their role in epilepsy with and without intellectual disability.78–80 Further sequencing studies and examination of smaller CNVs may refine the rules regarding overlapping susceptibility. Nonetheless, large, highly recurrent CNVs will remain as important causes of developmental disorders, and indeed a follow-up study to this one may need to examine combinations of large CNVs or genetic factors across these disorders.
