The patients with WNT1 variants mainly presented moderate (type IV) to severe (type III) symptoms, while those with COL1A1 and COL1A2 variants in our cohort were predominantly types I and IV,12,21 consistent with the concept that autosomal recessive OI is generally associated with more severe phenotypes.7 This evidence concerns the gene COL1A2 and osteogenesis imperfecta.