Mutations in COL10A1 are known to be responsible for two similar human skeletal dysplasias: spondylometaphyseal dysplasia and metaphyseal chondrodysplasia, Schmid type.(4, 5) Schmid metaphyseal chondrodysplasia (SMCD) is characterized by short stature, bowed legs, and coxa vara, suggesting defective long-bone development. The gene discussed is COL10A1; the disease is skeletal dysplasia.