Osteopetrosis may be inherited as either a dominant or recessive trait and is marked by increased bone density, brittle bones, and, in some cases, skeletal abnormalities. Although symptoms may not initially be apparent in people with mild forms of this disorder, trivial injuries may cause bone fractures due to abnormalities of the bone.
There are three major types of osteopetrosis: the malignant infantile form, the intermediate form, and the adult form. The adult form is milder than the other forms, and may not be diagnosed until adolescence or adulthood when symptoms first appear. The intermediate form, found in children younger than ten years old, is more severe than the adult form but less severe than the malignant infantile form. The malignant infantile form is apparent from birth and frequently shortens life expectancy. It is not related to cancer, despite the name.