Osteogenesis imperfecta (OI) is a rare inherited (genetic) bone disorder that is present at birth. It's also known as brittle bone disease. A child born with OI may have soft bones that break (fracture) easily, bones that are not formed normally, and other problems. Symptoms may range from mild to severe.

There are at least 8 different types of the disease. The types vary greatly, both within and between types. They are based on the type of inheritance (see below), and symptoms. These include findings on X-rays and other imaging tests. The OI types are:

• Type I. Mildest and most common type. About 50% of all affected children have this type. There are few fractures and deformities.
• Type II. Most severe type. A baby has very short arms and legs, a small chest, and soft skull. They may be born with fractured bones. They may also have a low birth weight and lungs that aren't well developed. A baby with type II OI often dies in the birth parent's uterus or a few weeks after birth.
• Type III. Most severe type in babies who don't die as newborns. At birth, a baby may have slightly shorter arms and legs than normal and arm, leg, and rib fractures. The baby may also have a larger than normal head, a triangle-shaped face, a deformed chest and spine, and breathing and swallowing problems. These symptoms are different in each baby.
• Type IV. Symptoms are between mild and severe. A baby with type IV may be diagnosed at birth. They may not have any fractures until crawling or walking, with most fractures occurring before puberty. The bones of the arms and legs may not be straight. The child may not grow normally.
• Type V. Similar to type IV. Symptoms may be medium to severe. It is common to have enlarged thickened areas (hypertrophic calluses) in the areas where large bones are fractured.
• Type VI. Very rare. Symptoms are medium. Similar to type IV.
• Type VII. May be like type II or like type III. It's common to have shorter than normal height. Also common to have shorter than normal upper arm and thighbones.
• Type VIII. Similar to types II and III. Very soft bones and severe growth problems.

OI is passed on through the genes. The different types are passed on in different ways. The gene may be inherited from one or both parents. Or the gene can be passed on from an unexplained change (spontaneous mutation) of a gene.

Most babies with OI have a defect of one of two genes. These genes help in forming collagen. Collagen is a main part of connective tissue that connects and supports the whole body, including the bones. Because of the defect, there is not enough collagen. Or the collagen is abnormal.

The symptoms of OI vary greatly within and between types. Symptoms of OI include:

• Easily broken bones
• Bone deformities, such as bowing of the legs
• Discoloration of the white of the eye (sclera), may be blue, purple, or gray in color
• A barrel-shaped chest
• A curved spine
• Short stature
• A triangle-shaped face
• Loose joints
• Muscle weakness
• Skin that easily bruises
• Hearing loss in early adulthood
• Breathing problems
• Soft, discolored teeth

Many of these symptoms can be caused by other medical conditions. Always see your child's doctor for a diagnosis.

Your baby's doctor will ask questions about your baby's medical history, your family and pregnancy history, and your baby's current symptoms. They will examine your baby, looking for symptoms of OI. The milder forms of OI may be hard to diagnose in a baby.

Your baby's doctor may refer you to specialists with experience in diagnosing and treating OI. For example, your baby may be referred to a specialist in genetic conditions (geneticist) or in bone disorders (orthopedist).

Your baby's doctor or the specialists may advise these tests:

• X-rays. These may show many changes, such as weak or deformed bones and fractures.
• Lab tests. Blood, saliva, and skin may be checked. The tests may include gene testing.
• DEXA (dual energy X-ray absorptiometry) scan. This is a scan of the bones to check for softening.
• Bone biopsy. A sample of the hipbone is often checked. This test needs anesthesia.

Treatment will depend on your child's symptoms, age, and general health. It will also depend on how severe the condition is.

The main goal of treatment is to prevent deformities and fractures and reduce chronic pain. And, once your child gets older, to allow them to function as independently as possible. Treatments for preventing or correcting symptoms may include:

• Bisphosphonate medicines. These are medicines that help to strengthen bones and prevent fractures. They may be used in most types of OI. They may be given by mouth or by I.V. (intravenous) line into a vein.
• Care of fractures. The lightest possible materials are used to cast fractured bones. To prevent further problems, it's advised that a child start moving or using the affected area as soon as possible.
• Orthopedic treatment. This may include bracing and splinting. Surgery may also be needed.
• Rodding. Metal rods are inserted to help hold in place (stabilize) and prevent deformities of long bones.
• Dental procedures. Capping teeth, braces, and surgery may be needed.
• Physical and occupational therapy. Both are very important in babies and children with OI.
• Assistive devices. Wheelchairs and other custom-made equipment may be needed as babies get older.

Complications may affect most body systems in a baby or child with OI. The risk of complications depends on the type and severity of your baby's OI. Complications may include:

• Respiratory infections, such as pneumonia
• Heart problems, such as poor heart valve function
• Kidney stones
• Joint problems
• Hearing loss
• Eye conditions and vision loss

OI is a lifelong condition. Managing it may include:

• Preventing fractures. If your baby has medium to severe OI, they need to be picked up, diapered, and dressed very carefully. Their position should be changed throughout the day. As your baby gets older, it will be important to help them prevent injuries. A physical or occupational therapist, as well as other doctors, can help.
• Preventing infection. Your baby may be more likely to get colds and other respiratory infections. And they may get sicker with an infection. Make sure your baby has all their advised vaccines (immunizations). During cold and flu season, keep your child away from crowds. Make sure you wash your hands and your child's hands well. As your child gets older, teach them how to do it.
• Managing pain. Fractures and deformities can be very painful. Talk with your baby's doctor about pain medicine or other ways to reduce pain.
• Coping with challenges. As your child gets older, they may have emotional and physical challenges.
• Getting regular medical and dental checkups. Your baby will need regular checkups and tests. These include eye and dental exams.
• Managing weight. When your child gets older, they may gain weight because of the decreased physical activity.

Contact the doctor if your child:

• Is injured
• Has changes in their behavior that may mean an injury or other problem. For example, your baby may be fussy or irritable.
• Has signs of a cold or flu, like a fever, chills, or cough

• Osteogenesis imperfecta (OI) is an inherited (genetic) bone disorder that is present at birth.
• It's also known as brittle bone disease.
• A child born with OI may have soft bones that break (fracture) easily, bones that are not formed normally, and other problems. Signs and symptoms may range from mild to severe.
• The main goal of treatment is to prevent deformities and fractures.
• OI is a lifelong condition.

Tips to help you get the most from a visit to your child's doctor:

• Know the reason for the visit and what you want to happen.
• Before your visit, write down questions you want answered.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you for your child.
• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
• Ask if your child's condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if your child does not take the medicine or have the test or procedure.
• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your child's doctor after office hours, and on weekends and holidays. This is important if your child becomes ill and you have questions or need advice.