Osteopetrosis: a rare disease with rare presentations

At least eight types of osteopetrosis have been described in humans. The primary underlying mechanism involved in all forms is the failure of normal osteoclastic bone resorption. Osteopetrosis tarda, the benign adult form, is inherited as an autosomal dominant trait. Patients typically are asymptomatic and have good long-term survival rates because bone marrow failure rarely occurs. A more common and malignant form, osteopetrosis congenita, presents in infancy and results in bone marrow failure caused by complete replacement of the marrow spaces with osteoclasts. Other forms are rare and have variable manifestations. In this communication we report 2 cases on possibly a rare form of osteopetrosis, the intermediate form