Two missense mutations (p.Lys147Glu and p.Gly259Val) in BGN, which encodes biglycan, cause the X-linked form of spondyloepimetaphyseal dysplasia in Korean, Indian, and Italian families, and are characterized by anomalies of the spine as well as the epiphyses and metaphyses of the long bones, resulting in a short stature and osteoarthritic changes in joints [65] (Table 1, MIM#300106). The gene discussed is BGN; the disease is spondyloepimetaphyseal dysplasia, matrilin-3 type.