A study (N = 487) reported that an insertion/deletion (INS/DEL) polymorphism (rs3917) in the 3′ UTR of COL1A2 was associated with risk of osteoporosis.23 The study demonstrated a significant reduction in BMD in the INS/DEL or DEL/DEL group versus the INS/INS group; subsequent in vitro study using 48 patients’ primary osteoblast showed that let‐7g could negatively regulate COL1A2 in osteoblast with INS/INS genotype but not with INS/DEL and DEL/DEL genotypes. Here, COL1A2 is linked to osteoporosis.