Mental Retardation and Abnormal Skeletal Development (Dyggve-Melchior-Clausen Dysplasia) Due to Mutations in a Novel, Evolutionarily Conserved Gene

Dyggve-Melchior-Clausen dysplasia (DMC) and Smith-McCort dysplasia (SMC) are similar, rare autosomal recessive osteochondrodysplasias. The radiographic features and cartilage histology in DMC and SMC are identical. However, patients with DMC exhibit significant developmental delay and mental retardation, the major features that distinguish the two conditions. Linkage studies localized the SMC and DMC disease genes to chromosome 18q12-21.1,...