Osteogenesis imperfecta is the best known disorder of a group of disorders that disturb bone growth. These disorders are called osteodysplasias. In osteogenesis imperfecta, synthesis of collagen, one of the normal components of bone, is impaired. The bones become weak and break (fracture) easily. There are 4 main types of osteogenesis imperfecta.
(See also Overview of Hereditary Connective Tissue Disorders Overview of Connective Tissue Disorders in Children Connective tissue is the tough, often fibrous tissue that binds the body's structures together and provides support and elasticity. Muscles, bones, cartilage, ligaments, and tendons are built... read more .)
Osteogenesis imperfecta can range from mild to severe. Most people with osteogenesis imperfecta have fragile bones, and about 50 to 65% have hearing loss. Osteogenesis imperfecta causes the whites of the eyes (sclerae Structure and Function of the Eyes The structures and functions of the eyes are complex. Each eye constantly adjusts the amount of light it lets in, focuses on objects near and far, and produces continuous images that are instantly... read more ) in some people to turn blue. The blue color appears because the veins beneath the abnormally thin sclerae show through. The sclerae are thinner than normal because collagen has not been formed correctly. Children may have discolored and poorly developed teeth (called dentinogenesis imperfecta) depending on the type of osteogenesis imperfecta. Sometimes heart or lung diseases develop in children with osteogenesis imperfecta.
Type I osteogenesis imperfecta is the mildest type. Some children may have only symptoms of blue sclerae and muscle and joint pain caused by loose joints. Children with this type may have increased risk of fractures during childhood.
Type II osteogenesis imperfecta is the most severe type and causes death. Infants are usually born with many broken bones. The skull may be so soft that the brain is not protected from pressure applied to the head during childbirth. These infants have shortened arms and legs and blue sclerae. Infants with this type can die before childbirth or within the first few days or weeks of life.
Type III osteogenesis imperfecta is the most severe type that does not cause death. Children with this type are very short and have curving of the spine and frequent fractures. This type causes bones to often break after very minor injuries, usually when children begin to walk. These children also have a large skull and a triangular face shape caused by overdevelopment of the head and underdevelopment of the face bones. Chest deformities are common. The color of the sclerae varies.
Type IV osteogenesis imperfecta is a moderate type. Children with this type have bones that fracture easily during childhood before puberty. The sclerae are typically white. Children are short. Children with this type may benefit from treatment.
Before birth, the most severe and lethal form of osteogenesis imperfecta can be detected in pregnant women by an ultrasound Ultrasonography Prenatal diagnostic testing involves testing the fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic... read more .
After birth, doctors base the diagnosis of osteogenesis imperfecta on the symptoms and on a physical examination.
If the diagnosis is not clear, doctors may remove a sample of skin for examination under a microscope (biopsy) to analyze a type of connective tissue cell (fibroblasts) or they may take a sample of blood to analyze certain genes.
X-rays X-rays A doctor can often diagnose a musculoskeletal disorder based on the history and the results of a physical examination. Laboratory tests, imaging tests, or other diagnostic procedures are sometimes... read more may show abnormal bone structure that suggests osteogenesis imperfecta.
A test called audiometry Worldwide, about half a billion people (almost 8% of the world's population) have hearing loss. More than 10% of people in the United States have some degree of hearing loss that affects their... read more is done often throughout childhood to monitor hearing.
Growth hormone injections can help children with types I and IV.
A type of drug called a bisphosphonate can help strengthen bones and lessen pain and the frequency of fractures. Bisphosphonates can be given by vein (pamidronate) or taken by mouth (alendronate).
Treatment of broken bones is similar to that for children who do not have the disorder. However, broken bones can become deformed or fail to grow. As a result, body growth can become permanently stunted in children with many broken bones, and deformities are common. Bones may require stabilization with internal metal rods. Physical therapy Physical Therapy (PT) Physical therapy, a component of rehabilitation, involves exercising and manipulating the body with an emphasis on the back, upper arms, and legs. It can improve joint and muscle function, helping... read more and occupational therapy Occupational Therapy (OT) Occupational therapy, a component of rehabilitation, is intended to enhance a person's ability to do basic self-care activities, useful work, and leisure activities. These activities include... read more help prevent fractures and improve function. Taking measures to avoid even minor injuries can help prevent fractures.
Some children with hearing loss may be helped by a cochlear implant Cochlear Implants Many causes of hearing loss have no cure. In these cases, treatment involves compensating for the hearing loss as much as possible. Most people with moderate to severe loss use hearing aids... read more (a device that converts sound waves to electrical signals that it sends to electrodes implanted in the inner ear).
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Osteogenesis Imperfecta (OI) Foundation: An organization providing support, education, and research information about OI