ACE2 and osteogenesis imperfecta: In the OI group, the serum ACE2 levels [1.46 (1.80) vs. 2.41 ± 1.33 pg/ml] (z = −3.66, P < 0.001) and Ang(1-7) levels [16.98 (21.89) vs. 38.07 (38.20) ng/ml, z = −6.43, p < 0.001] were significantly lower compared to the control group, with statistically significant differences (Figures 1A,B).