What is osteopetrosis? Osteopetrosis is a rare disorder that causes bones to grow abnormally and become too dense. When this happens, bones can break easily. In addition, bones may be misshapen and large, causing other problems in the body, such as problems with: Seeing and hearing. Fighting infection. Controlling bleeding. Osteopetrosis is a genetic disease that a child inherits from their parents. The disorder may be mild to severe, and symptoms may show up early after birth or later in adulthood.
What is alopecia areata? Alopecia areata is a disease that attacks your hair follicles (the part of your skin that makes hair). In most cases, hair falls out in small, round patches about the size of a quarter. This causes only a few bare patches. Some people may lose more hair. In only a few people, the disease causes total loss of hair on the head or loss of all body hair. Your hair may grow back, even if you lose all of it. But it may fall out again. No one can tell you when it might fall out