 [ Symptoms ] what is paget is disease [ Disease ] paget is disease is a long lasting chronic condition that causes abnormal bone growth bone is constantly being replaced as bone tissue is broken down and absorbed into the body then rebuilt with new cells in the early stages of paget is disease bone tissue is broken down and absorbed much faster than normal to keep up with the rapid breakdown of bone tissue the body speeds up the bone rebuilding process but this new bone is often weak and brittle causing it to break fracture more easily paget is disease usually affects the bones in the pelvis spine thigh  femur  skull shin tibia and upper arm  humerus  one bone or several bones may be affected by paget is disease webmd medical reference from healthwise this information is not intended to replace the advice of a doctor healthwise disclaims any liability for the decisions you make based on this information © 1995 2011 healthwise incorporated healthwise healthwise for every health decision and the healthwise logo are trademarks of healthwise incorporated