COL1A1 and osteogenesis imperfecta: Several biomarkers demonstrate relevance across populations: LRP5 mutations are associated with low BMD and higher fracture risk in both Asian and European groups [18–23] COL1A1 and COL1A2, encoding type I collagen, are linked to osteogenesis imperfecta and general bone fragility, with the Sp1 polymorphism in COL1A1 showing significant associations in both Asian and European cohorts [24–28].