COMAT Foundational Biomedical Science (FBS) Practice Exam – Study Guide & Prep

Osteogenesis Imperfecta (OI) is primarily caused by mutations in the genes responsible for collagen production, particularly the COL1A1 and COL1A2 genes. These genes encode for type I collagen, which is a crucial component of bone tissue. Mutations in these genes lead to a deficiency in the quantity or quality of collagen, resulting in bones that are brittle and prone to fractures, which is the hallmark characteristic of OI.

The COL1A1/2 mutations disrupt the normal assembly and structural stability of collagen fibers, manifesting in the clinical features of OI such as frequent fractures, blue sclera, and deformities of the bones. The severity of the condition can vary widely based on the specific type of mutation and the resulting impact on collagen structure.

In contrast, mutations in other genes listed, such as FGFR3 (associated with achondroplasia), TP53 (linked to various cancers), and BRCA1 (related to breast and ovarian cancers), do not pertain to bone development and are thus not involved in the pathogenesis of Osteogenesis Imperfecta. These mutations lead to other health issues unrelated to the collagen deficiencies that cause OI.