Osteopetrosis is a genetic disorder characterized by generalized increase in the skeletal bone density. Nine forms have been described.

Osteopetrosis with precocious manifestations – It is an autosomal recessive condition and presents in newborns leading to death at early age. It is characterized in the first few months of life with failure to thrive, malignant hypocalcemia, anemia, thrombocytopenia and fractures. Hyperostosis crowds the marrow cavity leading to extramedullary hematopoiesis and hepatosplenomegaly. Recurrent infections may occur due to defect in macrophage killing of bacteria. Blindness may occur due to bony encroachment on the optic foramina leading to optic atrophy and blindness. The X- Rays are diagnostic with findings showing generalized increase in bone density with defective metaphyseal modeling and a “bone in bone” appearance most marked in the vertebral bodies and loss of demarcation between the cortical and medullary cavity. Treatment consists of bone marrow transplant. Interferon gamma on long-term basis may also be useful. Prednisolone may be useful to prevent progression of anemia and thrombocytopenia. Oral cellulose phosphate and low calcium diet may be useful. For patients with blindness neurosurgical unroofing of optic foramina may be tried.

Osteopetrosis Tarda (Albers - Schonberg disease): It is an autosomal dominant condition and presents in late childhood as fractures, mild anemia or osteitis. It is characterized with increased density of cortical bones. Management consists of treatment of fractures and infections, periodic vision testing and transfusion/splenectomy for anemia.

Other intermediate forms and a type of osteopetrosis with renal tubular acidosis with cerebral calcifications have also been described.