COL10A1 and Schmid metaphyseal chondrodysplasia: Human metaphyseal chondrodysplasia type Schmid (MCDS; MIM156500) is an autosomal dominant disorder caused by heterozygous mutations in the NC1 domain of type X collagen, encoded by COL10A1 in hypertrophic chondrocytes (HC) (Warman et al., 1993; Wilson et al., 2005; Mäkitie et al., 2005).