About brittle bone disease

What is brittle bone disease?

Osteogenesis Imperfecta (OI) is a group of rare disorders affecting the connective tissue and characterized by extremely fragile bones that break or fracture easily (brittle bones), often without apparent cause. The specific symptoms and physical findings associated with OI vary greatly from case to case. The severity of OI also varies greatly, even among individuals of the same family. OI may be a mild disorder or may result in severe complications. Four main types of OI have been identified. OI type I is the most common and the mildest form of the disorder. OI type II is the most severe. In most cases, the various forms of osteogenesis imperfecta are inherited as autosomal dominant traits.



What are the symptoms for brittle bone disease?

Symptoms and signs of brittle bone disease vary according to the type. These can include:

  • Frequent fractures that lead to skeletal deformity
  • Short stature.
  • Bluish coloration to the whites of the eyes (sclerae).
  • Hearing loss.
  • Low birth weight and birth defects in certain forms.
  • Problems with tooth and jaw development.
  • Lung defects in some new borns.

 



What are the causes for brittle bone disease?

Brittle bone disease is caused by genetic defects, or mutations. These mutations can either be inherited from the parents or may arise on their own as new mutations.

Most cases of brittle bone disease are inherited from the parents (congenital) in an autosomal dominant manner, meaning that only one copy of the defective gene is necessary (from one parent) for the condition to be present. However, some forms of the condition may be inherited in an autosomal recessive pattern, meaning that two copies of a defective gene are required (one from each parent). Mutations in the COL1A1, COL1A2, CRTAP and P3H1 genes cause osteogenesis imperfecta. These genes code for proteins that are important for collagen formation. Collagen is an important component of bones and other body structures.



What are the treatments for brittle bone disease?

Osteogenesis imperfecta cannot be cured, and treatment is directed at managing symptoms and quality of life. Treatment goals include minimizing fractures and promoting general health and function. The treatment team may include primary care physicians, geneticists, rehabilitation specialists, endocrinologists, neurologists, orthopedic specialists, and pulmonologists.

Treatments can include surgical procedures to repair fractures or correct deformities. Medications such as bisphosphonates (approved for osteoporosis) are sometimes used to improve bone density. Mobility aids including walkers, crutches, and wheelchairs, may be used when needed.

 



What are the risk factors for brittle bone disease?

Brittle bone disease manifests in childhood. In the most severe forms, changes can even be identified in the fetus in utero.

Mutations in the COL1A1, COL1A2, CRTAP and P3H1 genes cause osteogenesis imperfecta. These genes code for proteins that are important for collagen formation. Collagen is an important component of bones and other body structures.



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