It can occur as an isolated trait or as a part of genetic syndromes such as amelogenesis imperfecta (AMELX or DLX3), Down syndrome (Trisomy 21), ectodermal dysplasia (EDA) and osteogenesis imperfecta (COL1A1 and COL1A2) [36–38]. The gene discussed is DLX3; the disease is trisomy 21.