There are several rare monogenic forms of bone fragility, the most common one being osteogenesis imperfecta (OI) which is mostly caused by dysregulation of COL1A1 and COL1A2 genes, involved in the production of collagen type I.4Collagen type I is vital for the bone extracellular matrix, providing strength and flexibility through its triple helical structure.5 The gene discussed is COL1A1; the disease is osteogenesis imperfecta.