Brittle bone disease is a genetic disorder, medically termed osteogenesis imperfecta, that has several types ranging from mild to severe. The National Institute of Arthritis Musculoskeletal and Skin Diseases explains that this disease is characterized by bones breaking easily with minimal cause. An estimated one in 20,000 individuals experiences brittle bone disease with equal frequency occurring across gender and race, the National Human Genome Research Institute notes. There is no cure for osteogenesis imperfecta and existing treatments aim to decrease the amount of incidence of bone fractures as well as facilitate optimal quality of life and health.
Collagen Rods
The Osteogenesis Imperfecta Foundation explains that abnormal collagen rods in bone alter the structure of bone resiliency. The collagen rods in osteogenesis imperfecta are shaped differently and in less quantity than that of normal bones. Essentially, a defect in the structure of collagen molecules causes a mutation in the DNA of the genes that create the collagen. The mutation produces deformed collagen and abnormal collagen fibers. The bones are never able to strengthen because the bad collagen fiber binds and consumes any existing healthy collagen fibers.The process is cyclical in a growing child and prevents new healthy and strong bones from forming. The result is increased fractures and breakage during youth. However, this process abates mildly after puberty when the process of bone growth slows.
Genetics
According to the National Human Genome Research Institute, most types of osteogenesis imperfecta result from an inherited autosomal dominant pattern. This means that if a child is born to a parent with a dominant mutation there is a 50 percent chance of the bone disease passing to the child. On the other hand, the National Institute of Arthritis Musculoskeletal and Skin Diseases explains that approximately 15 percent of cases of inherited osteogenesis imperfecta result from recessive mutation. Essentially, recessive mutation occurs when both parents carry the recessive gene for the disease but do not actually present with the disorder. The likelihood of being a carrier with the recessive gene and passing the trait on is 100 percent, but this does not indicate the disorder will occur in future generations.
Additional Factors
The Osteogenesis Imperfecta Foundation also explains that a significant reason for brittle bones in the disease comes from the osteoblasts being negatively affected by the bad collagen molecules. Osteoblasts are cells responsible for the formation of bone. Because of the poor quality of collagen fibers impacting the osteoblasts, new bone cells cannot form and divide properly.
References
- National Institute of Arthritis Musculoskeletal and Skin Diseases: Osteogenesis Imperfecta
- Osteogenesis Imperfecta Foundation: Understanding Bone Structure
- National Human Genome Research Institute: Learning About Osteogenesis Imperfecta
- Brittle Bone Society: Information About Osteogenesis Imperfecta
