ACAN and Familial osteochondritis dissecans: Mutations in ACAN gene can lead to a broad phenotype spectrum of nonfatal dysplasia of bone, including spondyloepiphyseal dysplasia, spondyloepiphyseal dysplasia Kimberley type, familial osteochondritis dissecans, and various idiopathic dwarf phenotypes.[6,7] ACAN encodes proteoglycan and extracellular matrix, both of which are key components for the structure and function of growth plate cartilage and other cartilage tissues,[8] which may be responsible for the pathogenesis of osteochondritis in some patients.