Spondyloepimetaphyseal Dysplasia, Aggrecan Type, also known as semd, aggrecan type, is related to spondyloepimetaphyseal dysplasia and osteochondrodysplasia. An important gene associated with Spondyloepimetaphyseal Dysplasia, Aggrecan Type is ACAN (Aggrecan). Affiliated tissues include bone, and related phenotypes are short neck and mandibular prognathia