Smith-McCort dysplasia is a rare autosomal recessive osteochondrodysplasia characterized by short limbs and trunk with barrel-shaped chest. The radiographic phenotype includes platyspondyly, generalized abnormalities of the epiphyses and metaphyses, and a distinctive lacy appearance of the iliac crest, ... Smith-McCort dysplasia is a rare autosomal recessive osteochondrodysplasia characterized by short limbs and trunk with barrel-shaped chest. The radiographic phenotype includes platyspondyly, generalized abnormalities of the epiphyses and metaphyses, and a distinctive lacy appearance of the iliac crest, features identical to those of Dyggve-Melchior-Clausen disease. Spinal cord compression due to atlantoaxial instability occurs in both SMC and DMC (Spranger et al., 1976; Nakamura et al., 1997). - Genetic Heterogeneity of Smith-McCort Dysplasia Smith-McCort dysplasia-2 (SMC2; 615222) is caused by mutation in the RAB33B gene (605950) on chromosome 18p.
Nakamura et al. (1997) examined iliac crest biopsies from 2 patients with Smith-McCort dysplasia. The lace-like appearance of the iliac crests, which is a characteristic radiologic sign, was caused by bone tissue deposited in a wavy pattern at ... Nakamura et al. (1997) examined iliac crest biopsies from 2 patients with Smith-McCort dysplasia. The lace-like appearance of the iliac crests, which is a characteristic radiologic sign, was caused by bone tissue deposited in a wavy pattern at the osteochondral junction. The growth plate showed abnormal enchondral ossification with no columnarization of chondrocytes. Electron microscopy demonstrated chondrocytes with dilated cisternae of rough endoplasmic reticulum (RER) containing fine granular or amorphous material similar to what had been reported in cases of DMC syndrome. Thus, Nakamura et al. (1997) concluded that Smith-McCort dysplasia has pathologic changes in common with DMC disease as an RER storage disorder, even though the mental condition is different.
In patients with SMC, Cohn et al. (2003) identified mutations in the DYM gene (607461.0005-607461.0006).
In an affected 6-year-old girl, offspring of consanguineous parents from the Portuguese Madeira Island, Santos et al. (2009) identified homozygosity for ... In patients with SMC, Cohn et al. (2003) identified mutations in the DYM gene (607461.0005-607461.0006). In an affected 6-year-old girl, offspring of consanguineous parents from the Portuguese Madeira Island, Santos et al. (2009) identified homozygosity for a mutation in the DYM gene (607461.0010).