Tricho-Dento-Osseous syndrome (TDO syndrome), a rare genetic disease, has been demonstrated to be caused by mutation of DLx3, with curly hair, enamel hypoplasia, dentinogenesis imperfecta, and increased density of jaw and skull bones (Lichtenstein et al., 1972). This evidence concerns the gene DLX3 and tricho-dento-osseous syndrome.