Brittle Bone Disease (Osteogenesis Imperfecta): Causes, Type and Symptoms

Brittle bone disease is a genetic disease that lasts a lifetime and makes bones break very easily, usually without any kind of injury. This can also be called osteogenesis imperfecta by your doctor. It occurs at birth and generally develops in children with a family history of illness. (1)

The disease is commonly referred to as osteogenesis imperfecta (OI), meaning “imperfectly formed bone.”

Brittle bone disease can vary from slight to serious. The majority of cases are benign, leading to some bone fractures. But serious forms of the disease can result in:

  • heart failure
  • hearing loss
  • Problem in spinal cord
  • permanent deformities

The osteogenesis imperfecta (IO) may sometimes be life-threatening if it happens to babies before or shortly after birth. Approximately one person in 20,000 will develop brittle bone disease. It is also found in men and women, as well as among ethnic groups. (2)

What Causes Brittle Bone Disease?

Brittle bone disease is the result of a defect, or flaw, in the gene that creates the type 1 collagen, a protein used in the creation of bones. The defective gene is generally heritable. In certain cases, however, a genetic mutation, or a change, may cause it.

What Are the Types of Brittle Bone Disease?

There are four different genes involved in producing collagen. Some or all of these genes may be affected in people who have osteogenesis imperfecta. Defective genes may produce eight types of brittle bone disease, labelled as Type 1 to Type 8 OIs. The top four types are more common. The remaining four are extremely rare, and most are Type 4 OI subtypes. The four most important types of osteogenesis imperfecta (OI) are:

Type 1 Osteogenesis imperfecta (OI)

Type 1 OI is the softest mild and most commonly occurring form of brittle bone disease. In this type of brittle bone disease, your body makes good collagen, but not sufficient. This leads to mildly fragile bones. Children with type 1 OI usually have bone fractures caused by minor injuries. These bone fractures occur significantly less frequently in adults. Tooth damage can also occur, leading to cracks and cavities.

Type 2 Osteogenesis imperfecta (OI)

Type 2 OI is the most serious form of brittle bone disease, and it may be deadly. In OI type 2, your body is not producing enough collagen or producing poor quality collagen. Type 2 OI may lead to bone deformities. If your child was born with a Type 2 OI, they may have a shrunken chest, broken or deformed ribs, or under-developed lungs. Infants with type 2 OI may die in the womb or soon after birth.

Type 3 Osteogenesis imperfecta (OI)

Type 3 OI is another serious form of brittle bone disease. Bones break quite easily. In type 3 OI, your child’s body produces sufficient collagen but it is of poor quality. Your child’s bones may even start to break before they are born. Bone deformities are common and may become more severe with age.

Type 4 Osteogenesis imperfecta (OI)

Type 4 OI is the most variable form of brittle bone disease, with symptoms ranging from mild to serious. As with type 3 OI, your body produces sufficient collagen but the quality is bad. Children with type 4 OI are usually born with curved legs, although the incline tends to decrease with age.

What Are the Symptoms of Brittle Bone Disease?

The symptoms of brittle bone disease are different depending on the type of disease. All people with fragile bone disease have fragile bones, but they vary in severity. Brittle bone disease is characterized by at least one of the following symptoms:

  • kyphosis
  • scoliosis
  • loose joints
  • weak teeth
  • blue sclera
  • bowed legs and arms
  • early hearing loss
  • respiratory problems
  • heart defects
  • bone deformities
  • multiple broken bones

How Is Brittle Bone Disease Diagnosed?

Your doctor can make an X-ray diagnosis of brittle bone disease. Radiographs allow your physician to view current and past fractures. They also allow you to see defects in bones more easily. Laboratory tests can be used for analysing your child’s collagen structure. In some cases, your physician may want to perform a skin punch biopsy. During this biopsy, the physician will use a pointed hollow tube to collect a small sample from your tissues.

Blood and urinary tests will eliminate other health problems that can lead to weak bones, like rickets.

Genetic tests can be carried out to find the source of any faulty gene.

How Is Brittle Bone Disease Treated?

There is no treatment for brittle bone diseases. But there are supportive therapies that help reduce the risk of your child having broken bones and improve their quality of life. brittle bone disease treatments include:

  • physiotherapy and occupational therapy to enhance your child’s mobility and muscular strength.
  • Bisphosphonate medicines to strengthen the bones of your child.
  • medication for pain reduction.
  • low impact workout to help build bones.
  • surgery for placing rods into the bones of your child.
  • reconstructive surgery for the correction of bone defects.
  • mental health advice to help address body image problems.

Long Term Outlook for Someone with Brittle Bone Disease?

Long-term prospects vary according to the type of brittle bone condition. Outlook four most common types of fragile bone diseases are:

Type 1 OI

If your child has type 1 OI, they may live a normal life with comparatively few problems.

Type 2 OI

Type 2 OI is often life-threatening. A type 2 OI child can die in the womb or shortly after the birth of breathing problems.

Type 3 OI

If your child has a Type 3 OI, he or she may have severe bone defects and often requires a wheelchair to travel. They generally have a shorter life expectancy than type 1 or 4 OI persons.

Type 4 OI

If your child has type 4 OI, they may require crutches for walking. But their life expectancy is pretty much normal.

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