Radiographic features of a 15-year-old boy with Smith- McCort dysplasia are presented. Dyggve-Melchior- Clausen syndrome without mental retardation has clinical and radiographic findings similar to those of Smith-McCort dysplasia. Both of these syndromes are rare autosomal recessive disorders affecting skeletal development. The radiographic appearance of generalized platyspondyly with double-humped end-plates, and the lace-like appearance of iliac crests are pathognomonic and distinctive of these syndromes. Diagnostic features of these diseases are compared with others like Morquio?s disease and spondylometaphyseal dysplasia, which may have similar vertebral changes, and are discussed in the light of the literature.

Keywords: bone disease, developmental, mental retardation