A 22q11.21 microdeletion encompassing the TBX1, SHANK3, SOX10, AP1B1, FBXO7, MYH9, and SPECC1L genes cause DiGeorge syndrome, which is associated with DD, ID, seizure, and cardiac malformations, with a prevalence of 1 in 4000 [58,59]. The gene discussed is TBX1; the disease is dentin dysplasia.