Albers-Schonberg osteopetrosis is a rare genetic disorder that affects the bones. It is characterized by abnormally dense bones that are prone to fractures and deformities. It is caused by a mutation in the gene that codes for the enzyme carbonic anhydrase II, which is responsible for regulating the amount of calcium in the bones. Symptoms of Albers-Schonberg osteopetrosis include bone pain, skeletal deformities, vision and hearing loss, and anemia. Treatment typically involves medications to reduce bone pain and deformities, as well as physical therapy to help maintain mobility.