In conclusion, our study describes significant clinical variability and expanded the phenotypic spectrum in Chinese patients diagnosed with OI type V. Also, we present the process of hypertrophic callus formation in detail for the first time, and found evidence of inflammation activity in patients with hyperplastic callus, which provides ideas for research on the pathogenic mechanism of the IFITM5 mutation causative of OI type V. However, the genotype-phenotype correlation still needs to be investigated in more patients. The gene discussed is IFITM5; the disease is osteogenesis imperfecta type 5.