TRAPPC2 and spondyloepiphyseal dysplasia tarda, X-linked: Mutations in Sedlin (also known as TRAPPC2), a component of the transport protein particle (TRAPP) complex operating between the ER and Golgi, a RAB GEF and possible vesicle-tethering factor (Barrowman et al., 2010), cause X-linked spondyloepiphyseal dysplasia tarda (SEDT) (Gedeon et al., 1999).