Phenotypic features of dentition in diastrophic dysplasia

Diastrophic dysplasia (DTD) is a well-characterized, recessively inherited osteochondrodysplasia. The gene, DTDST, in which mutations are responsible for the disease, codes for a sulphate transporter protein. We studied 53 patients with earlier diagnosed DTD for special characteristics in the oral region. Clinical examination included impressions of dental arches, oral photographs, and panoramic radiographs. Palatal clefting was recorded. Congenitally missing teeth were evaluated and dental maturity calculated from the panoramic radiographs. Tooth crown size and length and breadth of dental arches were measured from the casts. Dental anomalies and orthodontical status were evaluated from the casts and oral photographs. The level of oral hygiene was evaluated with caries (DMF) and periodontal (GBI) indices. Cleft palate was recorded in 56% and hypodontia (excluding third molars) in 31% of the patients. Dental age was retarded. Dental arches were narrow and tooth crown size was reduced. The observed crown size reduction could result from the same factors that cause cleft palate and/or hypodontia, or from a lack of sulfation in the developing dental papilla. The typical malocclusion traits were crowding, lateral crossbite, and open bite, which we assumed to result from reduced growth potential of the dental arches. Despite crowding and limited flexion of the finger joints leading to a severe handicap, the level of oral hygiene was high and no need for auxiliary equipment for cleaning the teeth was noted.