Osteogenesis imperfecta

Osteogenesis imperfecta (OI), also known as brittle bone disease, is a rare genetic disease affecting the connective tissue and bones. In this disease, bones become extremely fragile and break or fracture easily (osteoporosis). Infants born with OI may have fragile bones, abnormal bones, and other problems. There is a variation in the symptoms and severity of OI from person to person. Osteogenesis imperfecta can result in more severe complications. Signs and symptoms range from mild to severe.[1-3]

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There are eight types of OI, and the categorization is usually based on the underlying abnormalities at the genetic level or severity of the illness. These eight types of OI are described below:[4,5]

  • Type I: This is the most common and mildest type in children that occur before puberty. About half of the affected children have this type of OI. Few deformities and fractures occur due to mild to moderate trauma.

  • Type II: This is the most severe form. This is generally found in newborns, and the baby may be born with short arms and legs, a soft skull, and a small chest. An infant may also be born with fractured bones and has a low birth weight and under-developed lungs. Generally, infants die at the time of birth or in the womb of the mother.

  • Type III: This is the most severe form in newborns who remain alive. The illness further leads to a higher number of physical disabilities. At the time of birth, an infant may have arms and legs slightly shorter than normal, and fractures in arms, ribs, and legs. An infant may also have a larger head than a normal head, a deformed chest and spine, a triangle-shaped face, and swallowing and breathing problems. There are variations in these symptoms from child to child.

  • Type IV: The symptoms of this form range from mild to severe. Children with this form may have a diagnosis at birth and may not experience any fractures until walking or crawling. Most broken bones occur before puberty. The leg and arm bones may not be straight. The children may not grow normally.

  • Type V: This form is similar to type IV. Symptoms range from mild to severe. It is common to have large calluses referred hypertrophic calluses (enlarged, thickened areas) in the fractured parts or in surgical procedure sites.

  • Type VI: This very rare form. Symptoms and appearance are mild and similar to type V.

  • Type VII: Symptoms and appearance are similar to type II or type IV. It is common to have a shorter height, upper arm and thighbones than normal ones.

  • Type VIII: Symptoms and appearance are similar to types II and III. Bones are very soft. The patient also has severe growth problems.


The most common symptom of OI is weak, fragile bones. Following are the symptoms based on the type of OI:[4]

Type I:

  • Bones are prone to break from mild or moderate trauma

  • Most commonly occur before puberty

  • No change or slight changes to stature with ageing

  • Muscle weakness and loose joints

  • Blue, grey, or purple tint to the sclera (white area of the eyes)

  • Triangular face

  • Curved spine with a potential for compression of the spine bones with ageing

  • No or mild bone deformity

  • Possible alternations to colour and the strength of teeth

  • Possible hearing loss

  • Normal collagen structure, but less dense than the normal one

Type II:

  • Mostly leads to death at birth or shortly after, because of the failure to breathe

  • Many broken bones occur in the child when is still in the womb

  • Severe bone deformities

  • Very small stature

  • Underdeveloped lungs

  • Blue, grey, or purple tint to the sclera

  • Improperly formed collagen

Type III:

  • Easily fractured bones with minor trauma over a lifetime. Fractured bones are commonly present at birth, and x-rays may show healed bone cracks that happened before birth.

  • Small stature

  • Blue, gravy, and purple tint to the sclera

  • Loose joints

  • Poor muscle formations in legs or arms

  • Barrel-shaped rib cage

  • Triangular face

  • Curved spine and collapse or compression of backbones

  • Possible lung complications that worsen with ageing

  • Mostly severe bone deformity

  • Possible changes in colour and the strength of teeth

  • Possible hearing loss

  • Inadequately formed collagen

Type IV:

  • Bones fracture easily, perhaps before birth

  • Most fractured bones occur before puberty

  • Smaller than average stature

  • Blue or white tint to the sclera

  • Mild or moderate bone deformity

  • Backbone compression or collapse

  • Barrel-shaped rib cage

  • Possible changes to colour or strength of teeth

  • Triangular face

  • Possible hearing loss

  • Inadequately formed collagen

Type V:

  • On x-rays, a dense band is observed by the cartilage growth plate of the long bones

  • Unusually large calluses at fractures sites or surgical procedures

  • Calcification of the membrane between the forearm bones, ulna and radius, causing difficulty in arm movement

  • Possible loose joints

  • White sclera

  • No changes to teeth strength or colour

  • “Mesh-like” appearance to the bone when looked under the microscope

  • Changes in the bone minerals density

Type VI:

  • Not every time diagnosed at birth, symptoms may develop over time

  • “Fish-scale” appearance to the bone when looked under the microscope

  • Curved spine

  • Changes in the bone mineral density

Type VII

  • White sclera

  • Small stature

  • Short humerus (bone in the upper arm) and short femur (bone in the upper leg)

  • Smaller head size

  • Alterations in the process of forming collagen


  • White sclera

  • Small stature

  • Short humerus and short femur

  • Smaller head size

  • Changes in the process of collagen forming

Causes And Risk Factors


Osteogenesis imperfecta is caused by a defective gene that plays an important role in collagen production. Collagen is an important protein in bones and connective tissues. The collagen by defective genes is produced either in a lower amount or of poorer quality. If one of the parents has OI, then there are 50 per cent chance of the child having the illness. Sometimes, however, it may be possible that the disease occurs in children without a family history of OI.[6]

Risk Factors

A family history of OI increases the risk of certain types of OI. Most people with a defect in their genes inherit a defective gene from one parent. Sometimes, none of the parents transfers the defective gene.[7


Osteogenesis imperfecta is caused by genetic alternations or defects. No specific treatment exists to cure OI. If you have OI and planning to have a baby, you should have genetic counselling with a counsellor. He/she could tell you whether your child may have a risk of developing OI or not.[7]


The diagnosis of OI may be based on a clinical laboratory under the supervision of a physician. The physician observes many factors that are helpful in making a diagnosis of OI, including medical history, gestational history, family history, and physical examination. Special laboratory testing under the supervision of a geneticist is sometimes needed in case of suspected OI. Genetic testing is useful as all patients cannot be diagnosed correctly based only on physical examination, history, and radiographic findings. The tests used to diagnose OI are X-rays, bone mineral density test, and bone biopsy.[7,8]


There is no specific treatment for OI. Preventing bone fractures is the only treatment for people with OI. These treatments can lower the risk of bone fractures and are described below. The patients having OI should avoid activities that have the risk of falls or collisions, or activities that put high stress on the bones. They should do light exercises, such as swimming to make muscle strength and increase bone strength.

  • Physical Therapy: Physical therapy can be helpful for many children with OI. It builds up muscle strength, which helps to promote aerobic fitness, maintain function, and improve breathing. In younger children, physical therapy can help to develop motor skills.

  • Medicines: Doctors usually prescribe medicines for bone strengthening to increase bone density and decrease the chances of fractures. Some people need treatment for a lifetime to sustain bone strength.

  • Surgery: Surgery is required to repair a fractured bone or fix a deformity. Surgeons may insert a rod made up of metal into long bones like the tibia, femur, and humerus to prevent fractures. Surgery is also helpful to correct dental problems, fix hearing problems, bowing of bone, scoliosis (a condition that causes the backbones to curve) and heart problems. Surgery may also be helpful to maintain the ability to sit or stand.

  • Handling Fractures: When there is a fracture in the bones, get treatment with splints, casts, and braces right away. Orthopaedists, a doctor who specialized in treating bone problems, may recommend using light-weighted splints, casts, or braces that help some movement during healing.[9,10]


Depending on the type of OI, many people may live a quality of life. People with OI can improve bone health by achieving and maintaining a healthy body mass index, eating a healthy diet full of vitamin D and calcium, exercising as much as their physician recommends, limiting caffeine and alcohol intake, and quitting smoking.[11]


The following are the complication that may be presented with osteogenesis imperfect:[12]

  1. Hyperplastic callus formation: It is a rare condition.

  2. Osteogenic sarcoma – It is a cancer of bones.

  3. Basilar invagination: Involvement of cranial nerve, altered cerebrospinal fluid dynamics, and direct brain stem compression.

  4. Malignant hyperthermia: Both the anaesthesiologist and surgeon should take care of the possibility of malignant hyperthermia during anaesthesia. Malignant hyperthermia is a severe reaction to certain medications used for anaesthesia.


  1. Osteogenesis Imperfecta. NORD. Available at:

  2. Osteogenesis Imperfecta. Johns Hopkins. Available at:

  3. Osteoporosis. Radiopaedia. Available at:

  4. Osteogenesis Imperfecta Overview. NIH. Available at:

  5. Osteogenesis Imperfecta in Children. University of Rochester. Available at:

  6. Osteogenesis Imperfecta. Cedars Sinai. Available at: Osteogenesis Imperfecta. Beth Israel Lahey Health. Available at:

  7. Starr SR. Pediatrics in Review 2010, 31 (8) e54-e64

  8. Osteogenesis Imperfecta (Brittle Bone Disease). Kids Health. Available at:

  9. Osteogenesis Imperfecta (OI). CHOC. Available at:

  10. Osteogenesis Imperfecta (OI). Cleveland Clinic. Available at:

  11. Subramanian S. 2021. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from:


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