Diastrophic dysplasia (DTD)
Diastrophic dysplasia is a recessively inherited osteochondrodysplasia belonging to the group of disorders called the "Finnish Disease Heritage." Abnormalities in DTD seem to be restricted mainly to cartilage and bone. The main features include short-limbed short stature, generalized joint dysplasia, and spinal deformities. Mutations in the sulphate transporter gene DTDST in the long arm of chromosome 5 result in impaired sulphate uptake of the cells and reduced sulphation of the extracellular matrix macromolecules, particularly the proteoglycans. One-third of DTD patients have hypodontia in their permanent dentition; the lower second premolar, upper lateral incisor, and upper second premolar being the teeth most commonly missing. In addition, tooth crown sizes may be reduced. Cleft palate or submucous cleft palate is seen in 30% and 26% of the patients (Karlstedt et al, 1996).
Text adapted from Sirpa Arte: Phenotypic and genotypic features of familial hypodontia. Dissertation, Institute of Dentistry, University of Helsinki, Finland, 2001.
Text last edited 09.10.2003 by P.N. , page last created 10.12.2004 by P.N.