Osteocalcin is a protein responsible for bone mineralization, and PMI is a valuable parameter in the identification of patients with low bone mass [43], which suggests that statistically significant differences in the values of these parameters in patients with hemophilia A and B, compared to those in the control group, indicate that they were highly likely to be associated with osteopenia/osteoporosis. This evidence concerns the gene BGLAP and hemophilia A.