Oral abnormalities in the Saldino-Noonan syndrome.

The oral and dental features of a case of the Saldino-Noonan lethal short rib-polydactyly syndrome (SNS) are described. Natal teeth were noted. The anterior maxillary and mandibular fornices and the central labial frenula were absent. The tongue appeared larger than normal and lacked the sulcus terminalis and the vallate and foliate papillae. The tooth anlagen were abnormal. Microscopic studies revealed small tooth buds, in which hard tissue formation was more advanced than gestational age; abnormalities were noted primarily in the most recently formed dental tissue, indicating that the biochemical defect responsible for this disorder had acted abnormally on dentinogenesis mainly shortly prior to birth. Studies of oral and tooth development should be important to better understanding the abnormal function of the chondrodystrophy genes.