Osteogenesis imperfecta- type 2B
Overview
An inherited connective tissue disorder with extremely severe bone fragility. This is the lethal form of "brittle bone disease." Osteogenesis imperfecta type 2 is a recessive trait with males and females affected. Two copies of the mutant gene are needed to cause the disease.
Symptoms
The disease is characterized by short limb dwarfism, thin skin, soft skull, unusually large fontanels (soft spots), blue sclerae (whites of the eyes, small nose, low nasal bridge, inguinal hernia and numerous bone fractures at birth. There is bowing of limbs due to multiple fractures.
Prognosis
The prognosis for an individual with OI varies greatly depending on the number and severity of symptoms. Respiratory failure is the most frequent cause of death for people with OI, followed by accidental trauma. Despite numerous fractures, restricted activity, and short stature, most adults and children with OI lead productive and successful lives. They attend school, develop friendships and other relationships, have careers, raise families, participate in sports and other recreational activities, and are active members of their communities.
Treatment
There is not yet a cure for OI. Treatment is directed toward preventing or controlling the symptoms, maximizing independent mobility, and developing optimal bone mass and muscle strength. Care of fractures, extensive surgical and dental procedures, and physical therapy are often recommended for people with OI. Use of wheelchairs, braces, and other mobility aids is common, particularly (although not exclusively) among people with more severe types of OI. A surgical procedure called "rodding" is frequently considered for people with OI. This treatment involves inserting metal rods through the length of the long bones to strengthen them. The treatment also prevents and/or corrects deformities. For more information, see the OI Foundation's fact sheet on "Rodding Surgery." Several medications and other treatments are being explored for their potential use to treat OI. These include growth hormone treatment, treatment with intravenous and oral drugs called bisphosphonates, an injected drug called teriparatide (for adults only), and gene therapies. It is not clear if people with recessive OI will respond in the same manner as people with dominant OI to these treatments. The OI Foundation can provide current information on research studies and experimental treatments for OI, as well as information to help individuals decide whether to participate in clinical trials. People with OI are encouraged to exercise as much as possible to promote muscle and bone strength, which can help prevent fractures. Swimming and water therapy are common exercise choices for people with OI, as water allows independent movement with little risk of fracture. For those who are able, walking (with or without mobility aids) is excellent exercise. People with OI should consult their physician and/or physical therapist to discuss appropriate and safe exercise. Children and adults with OI will also benefit from maintaining a healthy weight, eating a nutritious diet, and avoiding activities such as smoking, excessive alcohol and caffeine consumption, and taking steroid medications - all of which may deplete bone and exacerbate bone fragility. For more information on nutrition, see the OI Foundation fact sheet titled "Nutrition."