Review Question - QID 4368

The diastrophic dysplasia sulfate transporter (DTDST) is the gene defect associated with diastrophic dysplasia. Cauliflower ears and hitchhiker's thumb are classic physical exam findings of diastrophic dysplasia.

Diastrophic dysplasia is an autosomal recessive form of short-limbed dwarfism caused by failure of formation of secondary ossification centers. Children with diastrophic dysplasia commonly have short stature, cauliflower ears, hitchhiker's thumb deformities, and kyphoscoliosis. In rare situations it is associated with atlantoaxial instability. Surgery is rarely needed, except when there is associated atlantoaxial instability with neurologic symptoms.

Horton et al. tried to determine the relationship and differences between so-called "diastrophic variant" and diastrophic dysplasia. Analysis of the combined clinical, radiographic, histologic, and genetic data showed that there can be wide variability in the phenotypic expression of diastrophic dysplasia.

Illustration A shows a clinical picture of a child with diastrophic dysplasia. Illustrations B and C show clinical pictures of a cauliflower ear and hitchhiker's thumb respectively.

Incorrect Answers:
Answer 1: Phenotype commonly found with osteogenesis imperfecta.
Answer 2: Phenotype commonly found with Down's syndrome.
Answer 4: Phenotype commonly found with Apert syndrome.
Answer 5: Phenotype commonly found with achondroplasia.