Osteogenesis imperfecta (OI), also known as brittle-bone disease, is a genetic (inherited) disorder characterized by bones that break easily without a specific cause. An estimated 20,000 to 50,000 people in the U.S. have this disease. OI can affect males and females of all races.
The cause of OI is believed to be because of a genetic defect that causes imperfectly formed or an inadequate amount of bone collagen, a protein found in the connective tissue.
The following are the most common symptoms for OI. However, each child may experience symptoms differently. Although symptoms may vary, generally they are used to classify the eight forms of OI, each of which represents varying grades of severity of the condition.
According to the Osteoporosis and Related Bone Diseases National Resource Center, part of the National Institutes of Health, the types of OI and their symptoms include:
Bones fracture easily
Can usually be traced through the family
Near normal stature or slightly shorter
Blue sclera (the normally white area of the eye ball)
Dental problems (brittle teeth)
Hearing loss beginning in the early 20s and 30s
Most fractures occur before puberty; occasionally women will have fractures after menopause
Tendency toward spinal curvatures
Most severe form
Newborns severely affected; frequently fatal, although a few have lived to adulthood
Severe bone deformity with many fractures
Usually resulting from a new gene mutation
Very small stature with extremely small chest and under-developed lungs
Bones fracture very easily
Tend to be isolated family incidents
Very small in stature
Fractures at birth very common
X-ray may reveal healing of fractures that occurred while in the uterus
May have hearing loss
Loose joints and poor muscle development in arms and legs
Barrel-shaped rib cage
Possible respiratory problems
Between Type I and Type III in severity
Can frequently be traced through the family
Bones fracture easily - most before puberty
Normal or near-normal colored sclera
Problems with teeth
Possible hearing loss
Similar to Type IV in frequency of fractures and skeletal deformity
Enlarged areas of bone where fractures have occurred – or even where fractures have not
Forearm movement can be restricted; dislocations can occur
Moderate in severity
Similar in appearance and symptoms to Type IV
Some cases resemble Type IV and others Type II, except that infants have white sclera, small heads and round faces
Short upper arm bones and thigh bones
Hip deformity is common
Similar to Types II or III, except for white sclera
Severe growth deficiency
Weakened skeletal bones
The symptoms of OI may resemble other bone problems or medical conditions. Always consult your child's health care provider for a diagnosis.
Because this is a genetic disorder, your child's doctor will take a careful family history in addition to a complete medical history and do a physical examination. Diagnostic procedures for OI may include a skin biopsy to evaluate the amount and structure of collagen. But this test is complicated, and not many qualified facilities are available to perform the procedure. It is not unusual for results of the biopsy to take up to six months.
Additional diagnostic tests include:
X-ray. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
Audiometry. This is a hearing test using electronic tones.
Ear, nose and throat exam. This is done to detect hearing loss
You may want to consider seeing a geneticist, a doctor who specializes in hereditary diseases. He or she can best help you understand your risk of having another child with OI and your child's risk of having a child with OI.
Specific treatment for OI will be determined by your child's health care provider based on the following:
Your child's age, overall health, and medical history
Extent of the condition
Type of condition
Your child's tolerance for specific medications, procedures, or therapies
Expectations for the course of the condition
Your opinion or preference
To date, no known treatment, medicine, or surgery will cure OI. The goal of treatment is to prevent deformities and fractures and allow the child to function as independently as possible. Treatments for preventing or correcting symptoms may include the following:
Care of fractures
Rodding, a procedure to insert a metal bar the length of a long bone to stabilize it and prevent deformity
Assistive devices, such as wheelchairs, braces, and other custom-made equipment
Management of the disease includes focusing on preventing or minimizing deformities and maximizing the child's functional ability at home and in the community. Management of OI is either nonsurgical or surgical. Nonsurgical interventions may include one or more of the following:
Regular exercise and a healthy diet. These are recommended for proper weight maintenance.
Positioning aids. These are used to help the child sit, lie, or stand.
Braces and splints. These are used to prevent deformity and promote support or protection.
Avoidance of smoking
Avoidance of steroid medications
Surgical interventions may be considered to manage the following conditions:
Bowing of bone
Scoliosis, a condition that causes the back bones to curve
Surgery may also be considered to maintain a child's ability to sit or stand.
OI is a progressive condition that needs life-long management to prevent deformity and complications.
The interdisciplinary health care team helps the family to improve the child's functional outcomes and to provide support to the parents as they learn to care for their child's needs.
The Osteogenesis Imperfecta Society can be an important resource for parents of children with OI.