Tricho-dento-osseous syndrome and precocious eruption.

Tricho-dento-osseous syndrome (TDO), an uncommon form of ectodermal dysplasia is an autosomal dominant genetic disorder which is characterized by inherited defects in tissues arising from epithelial-mesenchymal interaction. Genetic studies have revealed that it is caused by mutation in the DLX3 gene. TDO presents with a great phenotypic heterogeneity and studies have suggested that this heterogeneity is the result of environmental factors or other genetic modifiers. In this article, we report a case of TDO in which the child had typical clinical features of hair, teeth and bone defects, as seen in TDO. Parents of the child were unaffected. Genetic analysis of the child revealed mutation in DLX3 gene. The child also showed precocious eruption of the permanent molars, a clinical feature which has been rarely reported. We suggest that the precocious eruption seen in TDO is probably due to a markedly increased osteoblastic activity. Tricho-dento-osseous syndrome, DLX3 gene, precocious eruption.