COL1A2 and osteoporosis: It has recently been shown that a common coding polymorphism (rs42524) in the COL1A2 gene, which replaces alanine for proline at position Y of the helical region of alpha 2 (I) collagen, could be a genetic risk factor for aneurysms.26 This study was followed by several others studying the association of this polymorphism with osteoporosis and vascular disease.