Orthopaedic Nurses Certification Board (ONCB) Metabolic/Inflammatory/Tumors Practice Exam

The most common genetic cause of osteogenesis imperfecta is due to mutations in the COL1A1 or COL1A2 genes. Osteogenesis imperfecta, often referred to as "brittle bone disease," is primarily characterized by a defect in type I collagen, which is essential for the strength and integrity of bone. The COL1A1 and COL1A2 genes encode the two chains of type I collagen, making them critical in its synthesis. Mutations in either of these genes lead to a reduction in the production of normal collagen or the formation of defective collagen, resulting in the characteristic skeletal fragility associated with the condition.

The other genetic causes mentioned do not commonly relate to osteogenesis imperfecta. Mutations in the TP53 gene are more associated with tumor suppression rather than connective tissue disorders. Chromosomal deletions on chromosome 7 do not specifically link to osteogenesis imperfecta, as this condition primarily arises from specific collagen gene mutations. Lastly, while mutations in the FBN1 gene are related to Marfan syndrome, which affects connective tissue, they are not involved in the pathology of osteogenesis imperfecta. Thus, the association of COL1A1 and COL1A2 mutations with osteogenesis imperfecta is well-established,