COL1A1 and osteogenesis imperfecta: Taqi et al. did not directly address DI but noted that in their OI cohort (n = 154) tooth discoloration was more prevalent in individuals with certain COL1A1 and COL1A2 variants, particularly those with helical glycine substitutions (39% and 37%, respectively), compared to splice site variants (18%) or COL1A1 haploinsufficiency (4%).