Metabolic Bone Disease is an umbrella term referring to the weakening of bones due to a deficiency of certain minerals, specifically calcium, phosphorus, and vitamin D. It can be caused by either a dietary deficiency or lack of adequate exposure to sunlight. Signs of the disease include hard knobs on the long bones of the legs, bumps along the vertebrae in the back or tail, softening or hard swelling of the jaw, and softening of the plastron or carapace. Visible signs of the disease include a jerky gait while walking and repeated tremors while at rest. Recovery of the disease is possible through proper diet and proper monitoring of sunlight exposure.