Osteopetrosis Support Trust http://www.ost.org.uk
Providing information and advice for families with children with the bone and blood disease, osteopetrosis. There are detailed disease descriptions and contact details.
Perthes Association http://www.perthes.org.uk
Information and support for parents of children with Perthes disease and related conditions, including all forms of osteochondritis and M.E.D. (Multiple Epiphyseal Dysplasia).