TRAPPC2 and spondyloepiphyseal dysplasia: Spondyloepiphyseal dysplasias (SED) are characterized by chondrodysplasias with short-trunk disproportionate dwarfism.2, 3 Variants in the type II collagen (COL2A1) and the sedlin (SEDLgenes result in two main subtypes of SEDs; autosomal dominant SED congenita (OMIM 183900) and X linked recessive SED tarda (OMIM 313400) respectively.