Tricho-dento-osseous syndrome. Features of the hair and teeth.

Tricho-dento-osseous syndrome is a rare autosomal dominant hereditary disorder characterized by curly hair, enamel hypoplasia, taurodont teeth, and thickened cortical bone. A large kindred with this syndrome has been identified in North Carolina and characterized by pedigree analysis and clinical evaluation. Hair samples (N = 3) and an exfoliated primary tooth (N = 1) from persons with tricho-dento-osseous syndrome and hair and teeth from unaffected persons were examined. Scanning electron microscopy showed that the hair shaft morphology, diameter, and cuticular pattern and periodicity were similar for the tricho-dento-osseous syndrome and control samples. The affected tooth was examined using light microscopy and a scanning electron microscope that showed pitting hypoplasia of the enamel surface, an extremely large pulp chamber, and dentin that appeared structurally normal. The affected enamel was uniformly thin, only 10% the thickness of the control enamel. The bulk of this enamel showed no prism formation. This study indicates that although hair with tricho-dento-osseous syndrome often is clinically curly, it can be straight, and it does not appear to have unique ultrastructural features that are of diagnostic benefit. The dental characteristics of tricho-dento-osseous syndrome were the most consistent feature seen in this kindred.