May Be Caused by

 Common

Anemia

Carcinomatosis

Hyperparathyroidism

Immobilization

Multiple myeloma

Myelomatosis

Osteoporosis

Postmenopausal osteoporosis

Senile osteoporosis

Steroid medication

 Uncommon

Fibrogenesis imperfecta ossium

Gaucher disease

GM1 gangliosidosis

Mannosidosis

Membranous lipodystrophy

Niemann-Pick disease

Osteogenesis imperfecta

Polyostotic fibrous dysplasia

Singleton-Merten syndrome

Winchester syndrome