Fibrodysplasia Ossificans Progressiva

            Patient 3 has Fibrodysplasia Ossificans Progressiva. Patients with this disease have abnormal development of bone in parts of the body where bone is not typically present. The mode of inheritance is autosomal dominant. It is caused by a gene called ACVR1. The ACVR1 protein receptor is found in skeletal muscle and cartilage and regulates ossification. In this disease, the mutated ACVR1 protein is constitutively activated, which causes excessive proliferation of bone.