Furthermore, homozygous or heterozygous mutations in ACAN cause spondyloepimetaphyseal dysplasia Aggrecan type or dominant familial osteochondritis dissecans, respectively (Tompson et al., 2009; Stattin et al., 2010). The gene discussed is ACAN; the disease is spondyloepimetaphyseal dysplasia, matrilin-3 type.