These results provide new information on bone development and increase our understanding of human conditions that are caused by mutations in the gene encoding Col11a1, including Stickler syndrome, Marshall syndrome, Wagner syndrome, and fibrochondrogenesis, indicating that Col11a1 plays an essential role in the development of trabecular and cortical bone in addition to the essential role of Col11a1 in cartilage. The gene discussed is COL11A1; the disease is Marshall syndrome.