We observed significant ID, DD, and other comorbidities, such as behavior problems, in the well-defined or syndromic ASD genes—SCN2A, MECP2, FOXP1, ADNP, and ASXL3—which is consistent with the previous genotype–phenotype correlation analysis (Additional file 11: Data 5). The gene discussed is SCN2A; the disease is dentin dysplasia.