The purpose of this poster is to present the imaging spectrum of various mutations in the diastrophic dysplasia sulfate transporter (DTDST) gene, from the most severe to the least severe phenotypes. Familiarity with the phenotypic variants within this spectrum will allow the radiologist to suggest appropriate genetic testing to establish the definitive diagnosis.

The "chondrodysplasia family" concept as advocated by Spranger in 1988 states that distinct phenotypes with different degrees of severity may be caused by different mutations within a single gene. This concept has been validated through the study of genes encoding for type 2 collagen, fibroblast growth factor 3 (FGFR3), filamin B, and others. This phenotypic variability often exhibits some overlap, resulting in a continuum of clinical severity. This is particularly true for the DTDST gene.1 The gene encoding for the diastrophic dysplasia sulfate transporter (DTDST),...

The four major entities in the spectrum of DTDST gene mutations will be highlighted and contrasted below,arranged in order of the clinical and severity of the condition, from the most severe (achondrogenesis type 1B) through the least severe (recessive multiple epiphyseal dysplasia). Achondrogenesis type 1B (Ach 1b) Achondrogenesis type 1B (Ach 1b) is one of three radiographic subtypes of achondrogenesis which are radiographically similar but genetically quite distinct. Ach 1b was previously diagnosed on clinical, radiographic, and histological criteria, with a characteristic "ring about the...

Severe null sense mutations produce a phenotypically and radiographically distinct profile from partial-function mutations. Severe entities in this spectrum (Achondrogenesis type 1b and Atelosteogenesis type 2) share phenotypic and radiographic features. Gene defects resulting in partial function and hence milder disease (Diastrophic dysplasia and recessive MED) also share phenotypic and radiographic features that are distinct from the more severe defects seen in Ach 1b and AO-2. The overlap can be diagnostically challenging. It is important to recognize clinical and radiographic features of common skeletal dysplasias,...

Superti-Furga A, Rossi A, Steinmann B, Gitzelmann R. A chondrodysplasia family produced by mutation in the diastrophic dysplasia sulfate transporter gene: genotype/phenotype correlations. Am J Med Genet 1996; (63):144-147. Rossi A and Superti-Furga A. mutations in the diastrophic dysplasia transporter (DTDST) gene (SLC26A2): 22 novel mutations, mutation review, associated skeletal phenotypes and diagnostic relevance. Hum Mutat 2001; (17):159-171. Hastbacka J, de la Chapelle A, Mahtani MM, Clines G, et al. The diastrophic dysplasia gene encodes a novel sulfate transporter: positional cloning by fine-structure linkage disequilibrium...